STANDARD INFORMATION SHEET

STANDARD INFORMATION SHEET DECC Ref: D/4119/2011 Project Name DECC Reference Type of Project Operator Name D/4119/2011 Medium sized gas development in Southern North Sea Operator Address 40 Holburn Viaduct, London, EC1N 2PB, United Kingdom Licence Holders Equity owners (P1055): (Company No. 03386464) (38.75%), Centrica North Sea Gas Limited (Company No. SC182822) (48.75%), Bayerngas E&P Limited (Company No. 04969335) (12.5%) Short Description The development will comprise: the installation of the Cygnus Alpha (A) hub (a permanently manned complex consisting of three bridge-linked platforms); Cygnus Bravo (B) satellite wellhead platform (a not permanently attended installation); the drilling of ten gas production wells; installation of a 51km 24-inch export pipeline tied in to the existing ETS pipeline; a 5.9km intra-field pipeline to Cygnus B west north-west (292 ) of Cygnus A; and associated subsea infrastructure. It is planned that construction will start in April 2013 with first gas expected in November 2014. Wells will be drilled using a combination of water and oil based muds. Cuttings and water based mud will be discharged to sea. The wells will be pressure fractured and flared for clean-up and testing purposes. Wells that are fractured will back-produce sand and free water from the fracture process for the first three months of production. Pipelines will be trenched and buried using a displacement plough from either an anchor lay barge or a dynamically positioned vessel. Concrete mattressing and rock protection will be used at trench transition areas and at two pipeline crossings. The platforms at Cygnus A and B will be four to six legged steel jackets that will be secured using piles. The facilities are designed to deliver a maximum flow of 250 million standard cubic feet (mmscf) sweet dry gas per day along with 750 barrels of dry condensate. Communications between Cygnus A and B will be via a control umbilical and by line of sight. Cygnus A will have two dual fuel turbine driven power generators which will provide the necessary power requirements for both platforms. The only significant gas venting will occur from Cygnus B for planned inspections. Produced water will be separated on Cygnus A and B and discharged to sea. Anticipated Start April 2013 Other Statements Related to this Project Significant Environmental Impacts Identified Prepared By Phase 1 ES (D/4040/2009); PON15Bs for Cygnus Appraisal Wells 44/12a-3, 44/12a-4, 44/12a-5, 44/11a-D (PON15B/130, PON15B/174, PON15B/326, PON15B/307); Cygnus Exploration Well ES (W/2880/2005) GDF SUEZ E&P UK is aiming to limit environmental effects to low impact through project design, mitigation and operational controls. No impacts associated with the Cygnus development have been assessed as of Major significance, one impact has been assessed as of Moderate significance, the remainder of impacts are expected to have no or a low residual impact on the environment. During construction and production it is considered that the following activities may have an impact: pipeline trenching and burial, discharge of drill cuttings and chemicals, positioning of rock material and structures on the seabed, presence of exclusion zones and additional vessel movements, subsea noise, obstruction of shipping routes and the accidental spill of hydrocarbons or chemicals. However, in all instances the severity of these impacts is limited by the nature and composition of the environment and by the fact that the individual project activities are generally short-term and affect a localised area. The development will not affect the integrity of the Dogger Bank candidate Special Area of Conservation and will not have any long-term effects on the area. With mitigation measures in place, the Cygnus development will have a negligible to low impact on the environment. Metoc Ltd and CF00-00-EB-108-00001 Rev C1

NON-TECHNICAL SUMMARY INTRODUCTION is a wholly owned oil and gas exploration and production subsidiary of the GDF SUEZ Group and operator of the in the Southern North Sea (SNS). GDF SUEZ E&P UK plans to develop the Cygnus field through two new platforms; Cygnus Alpha (A) manned hub and Cygnus Bravo (B) not permanently attended installation (NPAI), with gas export via a new pipeline tied in to the Esmond Transportation System (ETS) pipeline. Gas export to the UK mainline will be via the ETS pipeline which terminates onshore at Bacton. The field will target the Carboniferous Westphalian and Permian Leman formations. In compliance with the regulatory requirements, and to responsibly manage any impacts from this mediumsized development, GDF SUEZ E&P UK has carried out an Environmental Impact Assessment (EIA) of the proposed development. The EIA process establishes the environmental baseline in the area of the proposed development, identifies environmental sensitivities, particularly with relevance to the concerns of stakeholders and regulatory bodies, evaluates relevant impacts and their significance, and finally proposes mitigation measures which the operator will implement to minimise these impacts. This document reports on the EIA process, its findings and conclusions. GOVERNING LEGISLATION Offshore gas developments are governed by a collection of international, European Community (EC) and UK laws, policies and institutional frameworks. These dictate the management goals and objectives which an environmental assessment may aim to achieve. The main UK regulations that apply to the project are: Petroleum Act 1998 Requires all offshore oil and gas development to apply to the Secretary of State (SoS) for consent to undertake the project. Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) (Amendment) Regulations 2007 These regulations implement the European Commission (EC) EIA and Public Participation Directives, and require an environmental statement to be submitted for offshore oil and gas projects and public participation in the consent process. Offshore Marine Conservation (Natural Habitats, &c.) Regulations 2007 (as amended in 2007 and 2010) These regulations implement in the UK the EC Habitats and Birds Directives and aim to protect marine species and wild birds from environmentally damaging activities. It is now an offence under the Regulations to deliberately disturb wild animals of a European Protected Species. Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 (amended in 2007) The regulations apply the EC Habitats and EC Birds Directives in relation to oil and gas projects on the UKCS. PROJECT JUSTIFICATION Currently oil and gas provide more than 75% of the UK s primary energy with natural gas from the UKCS satisfying 68% of domestic consumption in 2009 (OGUK 2010). The UK produces more gas than it consumes over a year leading to it being a net gas exporter since 1994. The current UK Government energy policy is to encourage a low carbon economy whilst ensuring a secure and affordable energy supply. In 2009, gas production was approximately 62,798 million m 3 however, it is estimated that gas production is declining by around 6% per year (OGUK 2011). When Cygnus comes on line in 2014, maximum capacity will be 7.1 million m 3 per day; although operation at production capacity is unlikely for an extended period, this development will provide a significant volume of gas to offset this production decline. The Cygnus development fits many of the UK energy policy objectives: It is a economically viable development that has been designed to maximise reserve recovery within an existing mature province It is a low carbon fuel CF00-00-EB-108-00001 Rev C1

It is a national resource that will help to contribute towards energy security In addition to the obvious benefits of increased security of supply and national reserves, as a low carbon fuel, the use of gas as a primary energy source has led to improvements in UK air quality and a reduction in overall greenhouse gas emissions (OGUK 2004). PROJECT ALTERNATIVES The consideration of alternatives to a proposed project is a requirement of many EIA processes and a standard requirement of the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) (Amendment) Regulations 2007. A comparison of alternatives helps to determine the best method of achieving the project by indicating the best available technology (BAT) or the best environmental practice (BEP) or at the very least the option which minimises environmental impacts. Over the last four years the Cygnus project has considered a number of different development options. Economic analysis, technical risk assessment and environmental studies have been conducted on export routes, development schemes and pipeline installation methods to ensure the options selected can be considered best practice. The first option reviewed was a small development initially consisting of a single NPAI which directed its gas to an existing pipeline, with future development of the field proposed in phases. Further appraisal wells identified that the field was larger than expected and the phased development would not be appropriate; options for full field development were therefore considered. The main decision in order to develop the full field was to determine which of four export routes would be most suitable. Two were discounted in the early stages as they required the gas to be landed in The Netherlands rather than the UK. Of the final two potential routes, it was vital to ensure that the option chosen provided a robust export solution that could handle the forecasted gas production over a field life of 35 years. The ETS route was chosen as it presented the best technical and commercial alternative. The project also considered alternative schedules. An Early Production System (EPS) was designed which would achieve first gas in October 2013, a year earlier than the base case. It was determined however, that the base case was preferable as additional information was still required to confirm the feasibility of the EPS. If it was identified that the EPS was not viable, the delay caused by waiting for this information would have affected the base case schedule. It was considered that the base case presented the lowest risk option. At an early stage of project planning it was identified that any export route would have to pass across an area of shallow sand bank within the Dogger Bank possible Special Area of Conservation (psac). The Dogger Bank is a unique, dynamic area of the North Sea and its designation as a psac means that any development within its boundaries has to ensure that project activities will not affect the structure or integrity of the bank. To inform project design, GDF SUEZ E&P UK commissioned a desk-top study to compare four different installation techniques commonly used in the SNS: self-burial; jetting; non-displacement ploughing; and displacement ploughing. Self-burial was rejected outright because of evidence that it has proved ineffective at achieving full burial in this area. Of the remaining three options, a combination of uncertainty about performance, technical limitations and commercial availability have led GDF SUEZ E&P UK to select the displacement trenching technique. PROJECT DESCRIPTION OVERVIEW The project is located in UK continual shelf (UKCS) Blocks 44/12a and 44/11a, approximately 155km northeast of the North Norfolk coastline and 35km west of the UK/Netherlands median line. It is within the Dogger Bank candidate Special Area of Conservation (csac), the boundaries of which lie 40km to the east and 35km to the south of the platforms. The export pipeline passes through the csac to the boundary 40km to the south-west of Cygnus A and extends 10km beyond this boundary. As illustrated below, the development will comprise of: The Cygnus Alpha (Cygnus A) hub, a permanently manned main platform with central production, processing and accommodation facilities. The Cygnus Bravo (Cygnus B) satellite wellhead platform, a not permanently attended installation (NPAI) tied back to the Cygnus A hub. The drilling of ten horizontal wells A 51km 24-inch export pipeline tied-in to the existing ETS pipeline CF00-00-EB-108-00001 Rev C1

A 5.9km 12-inch intra-field pipeline and umbilical to Cygnus B west north-west (292 ) of Cygnus A Associated subsea infrastructure It is expected that production will cease between 2024 and 2038 CF00-00-EB-108-00001 Rev C1

Development layout Diagram for illustrative purposes only and does not necessarily reflect exact layout of infrastructure CF00-00-EB-108-00001 Rev C1

SCHEDULE Construction activities will commence in April 2013 with first gas at Cygnus A anticipated for November 2014. Construction will be phased into four key stages (see Section 5.1): CONSTRUCTION Stage 1: 2013 campaign this involves installation of the Cygnus A wellhead platform (W), WYE Structure, subsea safety isolation valve (SSIV) structure, as well as laying and trenching the 24 pipeline and ETS pipeline tie-in during the Tyne/Trent/Bacton shutdown. Stage 2: 2014 campaign - the remaining Cygnus A Complex (processing and utilities (PU) Platform, accommodation and utilities (QU) Platform and bridges), will be installed. Stage 3: between 2014 and 2016 - Cygnus B satellite platform and both the intra-field pipeline and umbilical will be installed. Stage 4: between 2015 and 2016 installation of compression module and drilling of final well at Cygnus A. The Cygnus field will comprise two drilling centres: Cygnus A to develop the field in the east; and Cygnus B to develop the field in the west. Production wells will target either the Leman Sandstone or the Carboniferous reservoirs. All production wells will be drilled in sections using a combination of water based mud and oil based mud, with each section cement cased. Cuttings and water based mud will be discharged to sea either directly at the seabed or at the sea surface from the drilling rig. It is likely that pressure fracturing may be required for three of the production wells and all wells will be flared for a 24 hour period for the purposes of well bore clean-up and reservoir testing. The Cygnus A hub will comprise a central permanently manned installation with production, dehydration and compression facilities to support the whole Cygnus development. It will consist of three bridge linked platforms with a compression module added at a later date. A new 51km 24-inch pipeline will export processed gas from the platform to a new manifold tie-in point on the existing ETS pipeline. It is proposed that five wells will be drilled from Cygnus A. The Cygnus B satellite will develop outlying field targets which cannot be reached from wells on the hub facility. Located approximately 5.9km west north-west (292 ) of Cygnus A, it will be a NPAI wellhead platform from which a further five wells will be drilled. The NPAI will be tied back to Cygnus A via a new 12- inch intra-field gas production pipeline and umbilical line. All platforms will be piled steel jackets. The new pipelines will be laid by a dynamically positioned vessel or anchor lay barge. They will then be flooded with chemically treated seawater and trenched into the seabed using a displacement plough. The trench will be either mechanically or naturally backfilled. After tie-in the pipelines will be hydrotested and leak-tested before they are dewatered and finally commissioned. Concrete mattresses will be used at platform approaches and at the Cavendish-Murdoch and Tyne-Trent pipeline crossings to provide protection from dropped object and to stabilise unburied sections of line. The export pipeline will tie-in to the ETS pipeline via a new wye manifold and subsea valves skids. PRODUCTION Gas produced from the Cygnus field will flow under natural reservoir pressure without requirement for artificial lift. The Cygnus facilities are designed to deliver a maximum flow of 250 MMscfd (million standard cubic feet per day) (7.1 million m 3 /d) of dry sweet gas to the export pipeline to Bacton along with up to 750 bpd (barrels per day) (47.7 m 3 /d) of dry condensate. Cygnus A has been designed so that compression facilities can be added once pressure declines. The gas will be dehydrated on the Cygnus A hub so that corrosion and hydrate inhibitors are not required for transmission in the export pipeline and ETS pipeline. Gas from the Cygnus B platform will have some treatment for produced water, but it will not be fully dehydrated until it is processed on Cygnus A. A threeinch umbilical between Cygnus A and B will provide corrosion and hydrate inhibitors that will be injected into the gas stream at Cygnus B to protect the 24 inch intra-field gas pipeline. These chemicals will be recovered from the gas stream on Cygnus A and returned to Cygnus B via the umbilical for further use. Communications between Cygnus A and B will be via the umbilical and by line of sight. Cygnus A will have two dual fuel turbine driven power generators which will generate the necessary power requirements for both platforms. Cygnus A will have a continuous flare lit to dispose of gas in an emergency. Some venting will occur from Cygnus B. Flaring and venting will only be undertaken when necessary and the volume of gas disposed will be minimised where possible. CF00-00-EB-108-00001 Rev C1

Produced water will be separated on Cygnus A and B. Both platforms will be equipped with coalescing vessels and degassers to minimise oil in water concentrations before discharge to sea. Online oil in water measurement will be backed up by sampling on a regular basis at Cygnus A and on an opportunity basis at Cygnus B. Wells will return graded sand and carrier water from the fracture process for the first three months of production. Cygnus A will be fitted with sand removal and conventional water separation equipment to remove the sand and water from the gas stream. Sand and water will be sampled for contamination, and if compliant with regulatory limits, discharged to sea. DECOMMISSIONING Depending on reservoir performance and economic variables, it is expected that production will cease between 2024 and 2038 assuming that no further developments are tied back to the facilities. Well before the end of field life, arrangements for decommissioning will be developed in accordance with the prevailing UK government and international legislation. The development plan is based on the assumption that similar requirements to current legislation will be applicable. These requirements have been considered in the design of the facilities and during project planning. The impacts of decommissioning activities on the environment have not been assessed under the scope of this document as they will be the subject of a separate EIA. ACCIDENTAL EVENTS Three types of accidental event were considered by the EIA: hydrocarbon spills and leaks; chemical spills and leaks; and dropped objects. In accordance with the current UK legislation the accidental release of hydrocarbons from the identified potential worst case scenarios was modelled and assessed to characterise the extent of potential impacts. Three worst case scenarios were considered: Loss of well containment e.g., well blow out resulting in a spill of condensate at a rate of 2.8m 3 per hour Loss of rig inventory i.e., due to collision, resulting in a spill of 750m 3 of marine diesel Loss of containment in the export pipeline resulting in a spill of 0.151m 3 of condensate Condensate and diesel are light hydrocarbons that rapidly evaporate and disperse within the marine environment. The oil spill modelling indicated that in the worst case scenarios the spills only travel 2-3km from the incident and in the case of marine diesel will be completely evaporated and dispersed within 8 hours. There is no likelihood of spills crossing the UK / Netherlands international boundary (the closest median line) or reaching the UK coastline. ENVIRONMENTAL IMPACT AND MITIGATION Mitigation is an integral part of the Cygnus field development. All of the potential interactions between project activities and environment receptors are subject to either standard recognised best practice mitigation measures or to impact specific, feasible and cost effective mitigation. In general the mitigation proposed will be sufficient to reduce the effects of activities to below levels which will cause a significant impact. For those where mitigation is not enough, the residual impacts are detailed below with a discussion of the mitigation that will help to reduce the impact to the acceptable levels identified. The following table summarises the findings of the detailed EIA process undertaken in relation to the Cygnus project and its potential effects on the physical, biological and human environment. Receptor & Type of Impact Baseline & Impact Assessment Significance of residual impact Mitigation Construction Water Resources: Increased suspended sediment loads & turbidity Transient increase in suspended sediment loads during pipeline installation. Disturbance will occur against a background of seabed disturbance as a result of wave and tidal activity and is localised. The impact will be similar in magnitude to normal storm conditions. Pipeline route will be optimised. CF00-00-EB-108-00001 Rev C1

Receptor & Type of Impact Baseline & Impact Assessment Significance of residual impact Mitigation Seabed Conditions: Sediment contamination Sediments are clean with low levels of hydrocarbon and heavy and trace metal contamination. Drilling related contaminants will disperse over a wide area and are unlikely to be noticeable against background levels. Standard chemical management procedures will be in place. Only chemicals that are permitted and have been subject to a risk assessment will be discharged. Seabed Conditions: Change / disturbance of surface sediments. Change in seabed topography Surface sediments are largely fine sands with patches of sandy gravel. The seabed is gently undulating at Cygnus A and B (~22m water depth). Bathymetry increases steeply from the edge of the Dogger Bank reaching 48.8m at the ETS pipeline tie-in. Storm events in the project area are likely to disperse any suspended or deposited particles and seabed disturbance will be unnoticeable against background levels within a few months of construction activities ceasing. Trenching is likely to bring some of the underlying clay sediments to the surface at the ETS pipeline tie-in locally changing surface sediments. Pipeline route will be optimised. Benthic Ecology: Physical damage to individuals. Habitat removal. Smothering. The benthic community is typical of the Dogger Bank sandbank habitat being a moderately disturbed population with relatively few species and low abundance. No rare or protected species were identified in the baseline survey. A small area of habitat which is designated as part of the candidate SAC, when compared to the extent of sandy habitat in the region, will be lost during construction as rock material and structures are placed on the seabed. In areas which are disturbed but sediments remain unchanged recovery is likely to be in the region of three months to two years. Footprints on the seabed will be minimised through careful design and where possible, by positioning drilling rig legs in existing footprints on return to the sites. A fall-pipe and Remotely Operated Vehicle (ROV) will be used for rock positioning and only sufficient material will be used. Marine Mammals & Protected Species: Subsea noise which can cause physical injury or disturbance There are seven species of marine mammal known to occur in the project area, five of which are European Protected Species. Pile driving to secure the Cygnus platforms and subsea structures in place will be the main source of subsea noise. Piling of each structure will be undertaken in one 24 to 36 hour period. A noise assessment determined that injury thresholds will not be exceeded and although disturbance thresholds may be exceeded it will not be sustained disturbance and therefore there is negligible risk of an offence under the Habitats Regulations and Offshore Marine Conservation (Natural Habitats &c.) Regulations. The JNCC Statutory nature conservation agency protocol for minimising the risk of injury to marine mammals from piling noise (JNCC 2010) guidance will be followed. Marine Mammals: Increased risk of collision There are seven species of marine mammal known to occur in the project area. An increase in vessel activity may increase the risk of marine mammals being injured or killed by ship strikes. The number of vessels is not expected to be considerably more than present baseline levels and therefore the residual impact is considered to be low. None envisaged Protected Sites: Physical disturbance The development area is within the Dogger Bank csac, which has been designated on account of its sandbank feature. JNCC assessed the Dogger Bank as being highly vulnerable to physical disturbance. Construction activities will disturb 1.46km 2 of seabed of which1.22km 2 is within the csac; this is equivalent to 0.01% of the csac. No rare or protected benthic species were identified in Footprints on the seabed will be minimised through careful design and where possible, by positioning drilling rig legs in existing footprints on return to the sites. A fall-pipe and ROV will be used for rock positioning and only CF00-00-EB-108-00001 Rev C1

Receptor & Type of Impact Baseline & Impact Assessment Significance of residual impact Mitigation the baseline surveys. The EIA concluded that construction activities will not affect the integrity of the designated feature. sufficient material will be used. Commercial Fishing: Impact on vessel movement Shipping and Navigation: Impact on Vessel Movement The project area is moderately important for commercial fishing with a relatively high catch per unit effort and experiences a high density of shipping traffic. It is standard practice to establish a 500m radius safety exclusion zone around drilling rigs to prevent collisions. However, this will exclude fishing vessels from traditional grounds; although it is expected that vessels will be able to relocate. The collision risk assessment undertaken for the field concluded that there is sufficient sea room available for vessels to manoeuvre around exclusion zones, although some re-routing may be required. A 500m radius safety exclusion zone will be enforced around the drilling rig(s), platforms and subsea infrastructure during construction. Users of the sea will be notified of the project and activities via the Kingfisher Fortnightly Bulletins, Notices to Mariners and VHF radio broadcasts. All vessels will follow the IMO Standards and will be properly marked. Production Commercial Fishing: Impact on vessel movement Shipping and Navigation: Impact on Vessel Movement The project area is moderately important for commercial fishing with a relatively high catch per unit effort with a relatively high catch per unit effort and experiences a high density of shipping traffic. 500m radius safety exclusion zones will be established around the platforms for the duration of field life, permanently excluding fishing and shipping vessels. The collision risk assessment undertaken for the field concluded that there is sufficient sea room available for vessels to manoeuvre around exclusion zones, although some re-routing may be required. A 500m radius safety exclusion zone will be enforced around the platforms. Users of the sea will be informed of the structures presence via the Kingfisher Fortnightly Bulletins, Notices to Mariners and where appropriate VHF radio broadcasts. GDF SUEZ E&P UK will have a collision risk management plan in place for the proposed development. Accidental Events: Spill of chemicals or hydrocarbons (>1 tonne) Seabed Conditions & Protected Sites: Sediment contamination Benthic Ecology: Potential toxic effects Fish and Shellfish: Potential toxic effects Sediments may become contaminated if a breach of the pipeline occurred or in the instance of a loss of well control. The ratio of condensate to gas in the field is low and the high proportion of light fractions within the condensate mean it is readily biodegradable. The generally low background concentrations of THC and PAHs in sediments indicate that any change is unlikely to be sufficient to alter the classification of sediments from unpolluted. If the spill is at the seabed i.e., from a well blow out, there is the potential that hydrocarbon concentrations may reach a level that is toxic to benthic species. The benthic community is typical of a moderately disturbed community and recovery after an impact of this kind is expected within three months to two years. Eggs and juveniles are most vulnerable to toxicity, and fish and shellfish will be vulnerable to toxic effects from gas and condensate dissolved in the water column. If the incident occurred during particularly sensitive periods, it is possible that recruitment for that year could be affected, however given the size of the spawning and nursery grounds within the SNS, it is unlikely that this will be seen at population level. Accidental spills will be kept to a minimum through training, good housekeeping and through storage/handling procedures e.g., sumps, drains and bunding should catch accidental spills. Management controls will be in place in eliminate bunkering spills e.g., only bunkering during day light and in good weather. A location specific OPEP will be in place for the development. The OPEP will detail all emergency procedures that will be in place to minimise any spill. GDF SUEZ E&P UK has access to Tier 1, 2 and 3 oil spill response capabilities through Oil Spill Response (OSR). GDF SUEZ E&P UK is a member of OSPRAG which will provide support in a well blow out event. CF00-00-EB-108-00001 Rev C1

Receptor & Type of Impact Baseline & Impact Assessment Significance of residual impact Mitigation Seabirds: Smothering Modelling demonstrates that the worst case spill scenarios will evaporate or disperse within 8 hours and will only reach 2-3km from the spill point. Feathers of seabirds landing on the water may become contaminated with hydrocarbons, which in turn may be ingested. Seabird vulnerability to hydrocarbon pollution is high to very high between March and May and September to November. Should a spill occur during one of these sensitive periods an intervention response may be required to minimise the risk of smothering and species injury. Medium Pipeline integrity will be ensured by pre-commissioning testing. Control measures will be in place to ensure rapid response to loss of pipeline containment. Marine Mammals & Protected Species: Smothering Condensate or diesel spills may cause eye or skin irritation or respiratory problems in marine mammals. Although marine mammal abundances are typically low in the SNS there are resident populations of harbour porpoise and white-beaked dolphins in the project area. Should a spill occur an intervention response may be required to minimise the risk of species injury. Commercial Fishing: Impact on vessel movement Shipping and Navigation: The presence of a spill may require that fishing vessels and general shipping are excluded from an area for a short period during any clean-up activities. Although as modelling indicates that the maximum extent of a spill is in the order of 2-3km and diesel and condensate will evaporate within 8 hours the impact is likely to be short-term. Impact on Vessel Movement CUMULATIVE AND TRANSBOUNDARY IMPACTS The main concerns regarding the potential for cumulative impacts from the proposed development relate to impacts from activities at Cygnus interacting with: Other activities within the project Other oil and gas developments (past and future) Other marine users, such as windfarms, commercial fishing, marine aggregate extraction etc. Climate Change The project will have a small contribution to increased subsea noise levels during pile driving, the amount of rock material on the seabed and the decrease in area available for commercial fishing and navigation. GDF SUEZ E&P UK are in continued consultation with the operators of the Forewind wind farm development to ensure that cumulative impacts are managed and mitigated where appropriate. Overall, the EIA concluded that the significance of cumulative impacts will be low. The worst-case scenario oil spill modelling conducted to inform the EIA indicates that condensate / diesel will travel 2 to 3 km from the spill location, meaning the leading edge of the spill will still be 32km from the closest international boundary. In addition, cuttings dispersal modelling for the Cygnus exploration well (using PROTEUS) and similar modelling of other SNS wells indicate that drill cuttings become indistinguishable from sediments within 4.6km of the well location. These project aspects and all others with a potential to interact with environmental receptors have been fully considered and mitigated against, and therefore the EIA concluded that the project will not have a significant adverse environmental impact across the UK/Netherlands boundary. CF00-00-EB-108-00001 Rev C1

ENVIRONMENTAL MANAGEMENT SYSTEMS GDF SUEZ E&P UK is committed to maintaining high standards in health, safety and environmental performance and implements and operates a Business Management System (BMS) which includes all the management system elements for Quality, Health, Safety and Environment (QHSE). The QHSE Management System (QHSEMS) has been certified to ISO 14001 standards. The QHSEMS is an integral part of the overall management system and aims to provide an ongoing process for environmental risk identification, assessment and control as well as being a method of ensuring compliance with legal and regulatory responsibilities and company policies. GDF SUEZ E&P UK requires that all contractors, their subcontractors and suppliers have their own QHSEMS. A project specific HSE plan will be developed for Cygnus which describes how HSE aspects of the project will be managed, presents the key HSE requirements and defines HSE roles and responsibilities. The plan will also provide a method of tracking and monitoring progress in an auditable format. The plan will include management of the current status of statutory regulatory applications and notifications. A bridging document will be used to describe management structure, responsibilities, methodologies and emergency response procedures during construction. Mitigation measures identified in this ES will be adopted and bridged into the QHSEMS. CONCLUSIONS The Environmental Impact Assessment has established the following: The benthic community is typical of a moderately dynamic sandy substrate in the SNS with a biological community dominated by polychaetes, consistent with existing surveys in the region Aspects of the development will be located in the Dogger Bank csac which is protected as sandbanks which are slightly covered by seawater all the time No additional habitats or species of conservation significance under the UK s Offshore Marine Conservation (Natural Habitats, &c) (Amendment) Regulations 2010 were observed in the project area. Atmospheric emissions will be generated during construction and production. It is predicted that concentrations of NOX and SO2 will be below European Commission threshold values to protect human health and the environment within 500m of the discharge point. The CO2 emissions are representative of a field development of this size. Approximately 1.46km 2 of seabed will be disturbed by construction activities. It is expected that physical disturbance will be unnoticeable against background levels within a year of cessation of construction activities. Benthic communities in the footprint are expected to recover to pre-impact levels within three months to two years. Comparison of pre-drilling and post-drilling surveys indicates that there will be no evidence of drill cuttings within a few months, and although there may be elevated levels of contaminants within sediments, the classification will not change from unpolluted to polluted. There is a negligible risk of an offence occurring under the Conservation (Natural Habitats &c.) Regulations 1994 (as amended) and the Offshore Marine Conservation (Natural Habitats, &c.) Regulations 2007 (as amended in 2010) as a consequence of subsea noise generated from pile driving. The integrity and structure of the Dogger Bank csac will not be affected by the project With consideration of other development activity in the SNS, the project will have a small contribution to increased subsea noise levels, the amount of rock material on the seabed and the decrease in area available for commercial fishing and navigation. Overall the cumulative impacts will be low. There will be no transboundary impacts. Mitigation measures have been proposed to reduce the impacts on environmental receptors. The relevant UK Regulatory consents will be applied for and all emissions will be monitored within the conditions outlined on the permits. With mitigation measures in place, the Cygnus field development will have a negligible to low impact on the environment. CF00-00-EB-108-00001 Rev C1

CONTENTS 1.0 INTRODUCTION 1 1.1 THE DEVELOPER 1 1.2 PROJECT OVERVIEW 1 1.3 FORMAT OF THE ENVIRONMENTAL STATEMENT 6 1.4 ES AVAILABILITY 7 2.0 INSTITUTIONAL POLICY AND REGULATORY FRAMEWORKS 8 2.1 INTERNATIONAL CONVENTIONS, EC LAW, UK LAW AND POLICIES 8 2.2 SEA AND EIA GUIDELINES 9 2.3 UK INSTITUTIONAL FRAMEWORK 9 2.4 GDF SUEZ E&P UK CORPORATE POLICY 10 3.0 PROJECT JUSTIFICATION AND ALTERNATIVES 13 3.1 PROJECT JUSTIFICATION 13 3.2 ALTERNATIVES 16 4.0 IMPACT ASSESSMENT METHODOLOGY 22 4.1 ENVIRONMENTAL IMPACT ASSESSMENT PROCESS 22 4.2 CUMULATIVE AND INDIRECT IMPACTS 32 5.0 PROJECT DESCRIPTION 34 5.1 SCHEDULE 34 5.2 CONSTRUCTION 37 5.3 PRODUCTION 53 5.4 DECOMMISSIONING 57 5.5 PROJECT ACTIVITY SUMMARY 57 6.0 PROJECT FOOTPRINT 59 6.1 CONSTRUCTION 59 6.2 PRODUCTION 74 7.0 ACCIDENTAL EVENTS 78 7.1 TYPES OF ACCIDENTAL EVENT 78 7.2 PROBABILITY OF ACCIDENTAL EVENTS OCCURRING 79 7.3 OIL SPILL MODELLING 82 8.0 IMPACTS ON PHYSICAL ENVIRONMENT 90 8.1 AIR 90 8.2 CLIMATE CHANGE 93 8.3 WATER RESOURCES 96 8.4 SEABED CONDITIONS 103 9.0 IMPACTS ON BIOLOGICAL ENVIRONMENT 121 9.1 PLANKTON 121 9.2 BENTHIC ECOLOGY 123 9.3 FISH AND SHELLFISH 133 9.4 SEABIRDS 141 CF00-00-EB-108-00001 Rev C1

9.5 MARINE MAMMALS 149 9.6 PROTECTED SITES AND SPECIES 159 10.0 IMPACTS ON HUMAN ENVIRONMENT 167 10.1 COMMERCIAL FISHING 167 10.2 SHIPPING AND NAVIGATION 175 10.3 OTHER MARINE USERS 181 10.4 ARCHAEOLOGY 184 11.0 CUMULATIVE AND INDIRECT IMPACTS 187 11.1 OIL AND GAS DEVELOPMENTS 187 11.2 OTHER MARINE USERS 193 11.3 CLIMATE CHANGE 197 11.4 TRANSBOUNDARY IMPACTS 197 12.0 ENVIRONMENTAL MANAGEMENT 199 12.1 INTRODUCTION 199 12.2 GDF SUEZ E&P UK S QHSE MANAGEMENT SYSTEM (QHSEMS) 199 12.3 ORGANISATION 200 12.4 CYGNUS DEVELOPMENT MANAGEMENT PROCESS 201 12.5 AUDIT AND REVIEW 203 12.6 SUMMARY OF ENVIRONMENTAL COMMITMENTS AND MITIGATION MEASURES 203 13.0 CONCLUSIONS 208 13.1 THE PROJECT 208 13.2 EXISTING ENVIRONMENT 208 13.3 POTENTIAL IMPACTS 208 13.4 ENVIRONMENTAL MANAGEMENT 210 14.0 REFERENCES 211 CF00-00-EB-108-00001 Rev C1

Tables TABLE 1-1: PROJECT CO-ORDINATES 4 TABLE 1-2: STRUCTURE OF THE ES 6 TABLE 2-1: SUMMARY OF THE INTERNATIONAL CONVETIONS, EC LAE AND UK LAW 8 TABLE 3-1: LOW, MID AND HIGH CASE PRODUCTION FORECASTS 14 TABLE 3-2: PROS AND CONS OF ALTERNATIVE PIPELINE INSTALLATION TECHNIQUES 20 TABLE 4-1: SURVEY SPECIFICATIONS 25 TABLE 4-2: EXTRACT FROM THE CYGNUS ISSUES SCOPING MATRIX 28 TABLE 4-3: EXAMPLE DEVELOPMENT ACTIVITY, ASPECT AND IMPACT IDENTIFICATION 28 TABLE 4-4: ASSESSMENT PROCESS FOR IDENTIFICATION OF POTENTIAL IMPACTS 29 TABLE 4-5: RESIDUAL IMPACT ASSESSMENT CRITERIA 31 TABLE 5-1: CYGNUS CONSTRUCTION SCHEDULE 36 TABLE 5-2: PILE SIZES AND NUMBERS 39 TABLE 5-3: CYGNUS DEVELOPMENT WELL SUMMARY 41 TABLE 5-4: SPECIFICATION OF THE PIPELINES 47 TABLE 5-5: POWER GENERATION EQUIPMENT 54 TABLE 5-6: SUMMARY OF PROJECT ACTIVITIES AND ASPECTS 58 TABLE 6-1: CONSTRUCTION EXHAUST GAS EMISSIONS 59 TABLE 6-2: TOTAL EMISSIONS RESULTING FROM WELL TESTING (TONNES) 60 TABLE 6-3: TOTAL EMISSIONS RESULTING FROM WELL TESTING CONDUCTED ON HYDRAULICALLY FRACTURED WELLS 61 TABLE 6-4: SUMMARY OF CONSTRUCTION AIRBORNE NOISE SOURCES AND ACTIVITIES 61 TABLE 6-5: SUMMARY OF ANTICIPATED CHEMICAL USE AND DISCHARGES FROM ALL WELLS (SLIM BORE) (TONNES) 63 TABLE 6-6: SUMMARY OF PIPELINE DISCHARGES 64 TABLE 6-7: TOTAL WASTE WATER DISCHARGE (M3) DURING CONSTRUCTION 65 TABLE 6-8: SUMMARY OF CONSTRUCTION UNDERWATER NOISE SOURCES AND ACTIVITIES 66 TABLE 6-9: SUMMARY OF UNDERWATER NOISE PRODUCED DURING CONSTRUCTION ACTIVITIES 66 TABLE 6-10: CYGNUS PLATFORMS SEABED FOOTPRINT (M2) 67 TABLE 6-11: WEIGHT AND DISCHARGE FATE OF DRILL CUTTINGS 68 TABLE 6-12: SUMMARY OF PIPELINE INSTALLATION FOOTPRINT OF THE SEABED 71 TABLE 6-13: SUMMARY OF ALL SEABED FOOTPRINTS 73 TABLE 6-14: EMISSIONS FROM POWER GENERATION 74 TABLE 6-15: PRODUCTION - VESSEL EXHAUST GAS EMISSIONS (PER ANNUM) 74 TABLE 6-16: SUMMARY OF PRODUCTION NOISE SOURCES AND ACTIVITIES 75 TABLE 6-18: TOTAL WASTE WATER DISCHARGE (M3) PER YEAR DURING PRODUCTION 76 TABLE 7-1: INDUSTRY RISER AND PIPELINES FAILURE FREQUENCIES 81 TABLE 8-1: SUMMARY OF 2010 ANNUAL EMISSIONS TO AIR AT MIDDLESBROUGH MONITORING STATION 91 TABLE 8-2: AIR QUALITY - POTENTIAL IMPACT IDENTIFICATION 91 TABLE 8-3: CLIMATE CHANGE - POTENTIAL IMPACT IDENTIFICATION 94 TABLE 8-4: COMPARISON OF UK AND CYGNUS CO2 EMISSIONS - ANNUAL 95 TABLE 8-5: SUMMARY OF CONTAMINANT LEVELS TYPICALLY FOUND IN SURFACE WATERS OF THE NORTH SEA 97 TABLE 8-6: DIRECTIONAL CURRENT SPEED PROFILES AT DEPTH 99 TABLE 8-7: WATER RESOURCES IMPACT IDENTIFICATION 100 TABLE 8-8: SUSPENDED SEDIMENT SETTLING PERIODS 102 TABLE 8-9: SUMMARY OF SURFACE SEDIMENT PARTICLE SIZE DISTRIBUTION FOR CYGNUS A LOCATION 107 CF00-00-EB-108-00001 Rev C1

TABLE 8-10: SUMMARY OF SURFACE SEDIMENT PARTICLE SIZE DISTRIBUTION FOR CYGNUS B LOCATION 108 TABLE 8-11: SUMMARY OF SURFACE SEDIMENT PARTICLE SIZE DISTRIBUTION FOR PIPELINE ROUTES 109 TABLE 8-12: COMPARISON OF SEDIMENT CHARACTERISTICS ACROSS THE DOGGER BANK 110 TABLE 8-13: SEABED CONDITIONS POTENTIAL IMPACT IDENTIFICATION 117 TABLE 9-1: PLANKTON POTENTIAL IMPACT IDENTIFICATION 122 TABLE 9-2: BENTHIC BIOTOPES TYPICAL OF THE DOGGER BANK 125 TABLE 9-3: BENTHIC COMMUNITIES RECORDED ACROSS THE DOGGER BANK 126 TABLE 9-4: INDIVIDUALS AND TAXA IDENTIFIED DURING CYGNUS A SURVEY 127 TABLE 9-5: INDIVIDUALS AND TAXA IDENTIFIED DURING CYGNUS B SURVEY 128 TABLE 9-6: INDIVIDUALS AND TAXA IDENTIFIED ALONG THE EXPORT AND INTRA-FIELD PIPELINE ROUTES 129 TABLE 9-7: BENTHIC ECOLOGY - POTENTIAL IMPACT IDENTIFICATION 130 TABLE 9-8: COMMONLY CAUGHT FISH AND SHELLFISH 134 TABLE 9-9: SUMMARY OF SPAWNING AND NURSERY ACTIVITY 135 TABLE 9-10: ELASMOBRANCHS PRESENT IN THE SNS AND PROJECT AREA 136 TABLE 9-11: FISH AND SHELLFISH POTENTIAL IMPACT IDENTIFICATION 138 TABLE 9-12: SPECIES SPECIFIC ACTION PLANS 143 TABLE 9-13: SEABIRD VULNERABILITY IN THE VICINITY OF BLOCKS 44/11A AND 44/12A 144 TABLE 9-14: SEABIRDS POTENTIAL IMPACT IDENTIFICATION 146 TABLE 9-15: CETACEAN OBSERVATIONS IN THE AREA OF INTEREST 150 TABLE 9-16: CETACEAN POPULATION ESTIMATES AND CONSERVATION STATUS 151 TABLE 8 17: MARINE MAMMAL - POTENTIAL IMPACT IDENTIFICATION 152 TABLE 9-18: RECEIVED LEVELS AT 400M BY SPECIES 156 TABLE 9-19: RECEIVED LEVELS AT WHICH CETACEANS DEMONSTRATE BEHAVIOURAL RESPONSES 156 TABLE 9-20: SEL AT DISTANCE FROM SOURCE 157 TABLE 9-21: ANNEX I HABITATS AND ANNEX II SPECIES 161 TABLE 9-22: PROTECTED SITES AND SPECIES - POTENTIAL IMPACT IDENTIFICATION 164 TABLE 10-1: ANNUAL LANDINGS AND VALUE FROM ICES RECTANGLE 38F2 (2002-2010) 168 TABLE 10-2: VALUE ( ) OF 5 MOST IMPORTANT SPECIES FOR THE CYGNUS DEVELOPMENT AREA AND SURROUNDING REGION (2002-2010) 168 TABLE 10-3: COMMERCIAL FISHING POTENTIAL IMPACT IDENTIFICATION 173 TABLE 10-4: SHIPPING ROUTES PASSING THROUGH THE DEVELOPMENT AREA 177 TABLE 10-5: ESTIMARED COLILISION RISK FOR THE TWO MAIN HAZARD SCENARIOS AT CYGNUS 178 TABLE 10-6: CYGNUS TOTAL COLLISION FREQUENCIES DURING NORMAL AND DRILLING OPERATIONS 179 TABLE 10-7: SHIPPING AND NAVIGATION- POTENTIAL IMPACT IDENTIFICATION 180 TABLE 10-8: OTHER MARINE USERS POTENTIAL IMPACT IDENTIFICATION 183 TABLE 10-9: ARCHAEOLOGY POTENTIAL IMPACT IDENTIFICATION 185 TABLE 11-1: PAST, PRESENT AND PLANNED DEVELOPMENTS IN THE VICINITY OF CYGNUS 188 TABLE 11-2: ESTIMATED FOOTPRINT OF GAS DEVELOPMENTS IN THE DOGGER BANK CSAC 192 TABLE 12 1: SUMMARY OF ALL CYGNUS STANDARD MITIGATION MEASURES AND REGULATORY REQUIREMENTS 205 CF00-00-EB-108-00001 Rev C1

Figures FIGURE 1-1: CYGNUS FIELD STRUCTURE SHOWING COMPOSITE FAULT BLOCKS 2 FIGURE 1-2: PROJECT LOCATION 4 FIGURE 2-1: GDF SUEZ E&P UK HEALTH, SAFETY AND ENVIRONMENTAL POLICY 11 FIGURE 2-2: GDF SUEZ E&P UK QUALITY POLICY 12 FIGURE 3-1: CYGNUS LOW, MID, AND HIGH CASE FORECASTS 15 FIGURE 4-1: OVERVIEW OF EIA METHODOLOGY 22 FIGURE 4-2: CYGNUS FIELD DEVELOPMENT SURVEY EXTENTS 26 FIGURE 4-3: RESIDUAL IMPACT SIGNIFICANCE ASSESSMENT PROCESS 32 FIGURE 5-1 CYGNUS FIELD DEVELOPMENT LAYOUT 35 FIGURE 5-3: DELTA FLIPPER ANCHOR 40 FIGURE 5-4: EXTENT OF ANCHOR SPREAD 42 FIGURE 5-5: POSITIONING JACK-UP RIG 48 FIGURE 5-6: TYPICAL DISPLACEMENT PLOUGH 49 FIGURE 5-7: TYPICAL TRENCH CREATED BY DISPLACEMENT PLOUGH 51 FIGURE 5-7: CYGNUS A TO ETS PIPELINE WYE MANIFOLD 52 FIGURE 5-10: CROSS SECTION THROUGH THE TYNE TO TRENT PIPELINE CROSSING 52 FIGURE 5-11: ROCK DEPOSITION BY FALL PIPE OVER PIPELINE CROSSING 52 FIGURE 6-1: AREA OF SEABED COVERED BY DEVELOPMENT WELL CUTTINGS PILES 69 FIGURE 6-2: CUTTINGS MODEL OVERLAY 72 FIGURE 7-1: STOCHASTIC MODEL OF WORST CASE CONDENSATE WELL BLOWOUT 2.7917M3/HR (670M3) RELEASED OVER 10DAYS 83 FIGURE 7-2: TRAJECTORY MODEL - 670M3 CONTINUOUS CONDENSATE SPILL OVER 10 DAYS WITH 30 KNOT WIND TOWARDS UK COASTLINE 84 FIGURE 7-3: TRAJECTORY MODEL - 670M3 CONTINUOUS CONDENSATE SPILL OVER 10 DAYS WITH 30 KNOT WIND TOWARDS CLOSEST INTERNATIONAL BOUNDARY FIGURE 7-4: STOCHASTIC MODEL OF WORST CASE SPILL OF 750M3 INSTANTANEOUS RELEASE FROM DRILLING RIG 86 FIGURE 7-5: TRAJECTORY MODEL - 750M3 INSTANTANEOUS DIESEL SPILL WITH 30 KNOT WIND TOWARDS UK COASTLINE 87 FIGURE 7-6: TRAJECTORY MODEL - 750M3 DIESEL SPILL WITH 30 KNOT WIND TOWARDS CLOSEST INTERNATIONAL BOUNDARY 88 FIGURE 8-1: ANNUAL WIND ROSE FOR THE CYGNUS DEVELOPMENT 92 FIGURE 8-2: ANNUAL CURRENT ROSE FOR CYGNUS DEVELOPMENT 98 FIGURE 8-3: BATHYMETRY - PROPOSED CYGNUS A LOCATION 104 FIGURE 8-4: BATHYMETRY - PROPOSED CYGNUS B LOCATION 105 FIGURE 8-5: BATHYMETRY - PROPOSED PIPELINE ROUTES 106 FIGURE 8-6: PHOTOGRAPHS OF SEABED TAKEN DURING ENVIRONMENTAL BASELINE SURVEY 111 FIGURE 8-7: POSSIBLE RELIC BIOGENIC REEF AT CYGNUS A LOCATION (CAM1 TRANSECT) 114 FIGURE 8-8: CYGNUS A - SEABED FEATURES 116 FIGURE 9-1: SANDEELS 135 FIGURE 9-2: HERRING 136 FIGURE 9-3: LOCATION OF SPAWNING AND NURSERY GROUNDS 137 FIGURE 9-4: KITTIWAKE IN FLIGHT 141 FIGURE 9-5: ANNUAL SEABIRD VULNERABILITY 145 FIGURE 9-6: HARBOUR PORPOISE 150 FIGURE 9-7: MINKE WHALE 150 FIGURE 9-8: GREY SEAL 151 FIGURE 9-9: FREQUENCY SPECTRUM OF RAMMING PULSES 155 CF00-00-EB-108-00001 Rev C1

FIGURE 9-10: PROTECTED SITES AND HABITATS 162 FIGURE 10-1: SEASONAL VARIATION IN FISHING ACTIVITY 169 FIGURE 10-2 SUMMARY OF CYGNUS AREA LANDINGS AND EFFORT DATA 170 FIGURE 10-3: FISHING DENSITY 171 FIGURE 10-4: FISHING VESSELS WITHIN 2NM OF CYGNUS BY NATIONALITY 171 FIGURE 10-5: FISHING VESSELS BY TYPE 172 FIGURE 10-6: SNS SHIPPING TRAFFIC 176 FIGURE 10-7: SHIPPING ROUTE POSITIONS NEAR CYGNUS 177 FIGURE 10-8: VESSEL TYPE DISTRIBUTION NEAR CYGNUS 178 FIGURE 10-9: OTHER MARINE USERS 182 FIGURE 10-10: SPECULATIVE RECONSTRUCTION OF THE RIVER COURSES ACROSS THE NORTH SEA FLOOR 184 FIGURE 11-1: OIL & GAS CUMULATIVE IMPACTS 189 FIGURE 11-2: DOGGER BANK TRANCHE A AND PROJECT ONE 194 FIGURE 11-3: CUMULATIVE NOISE IMPACT SCENARIOS 195 FIGURE 12-1: STRUCTURE OF GDF SUEZ E&P UK S QUALITY, HEALTH, SAFETY AND ENVIRONMENT MANAGEMENT SYSTEM 200 CF00-00-EB-108-00001 Rev C1

APPENDICES APPENDIX 1 - KEY POLICY, LAW AND GUIDELINES 219 APPENDIX 2 - ENVIRONMENTAL IMPACT ASSESSMENT 223 APPENDIX 3 - CHEMICAL SUMMARY 273 APPENDIX 4 - OIL SPILL MODELLING 283 APPENDIX 5 - SEASONAL WIND ROSES 294 APPENDIX 6 - JNCC RISK ASSESSMENT FLOW CHARTS 299 TABLES APPENDIX TABLE 4-1: SPILL SCENARIOS MODELLED 285 APPENDIX TABLE 4-2: MODELLING RESULTS 286 FIGURES APPENDIX FIGURE 4 1 : SCENARIO 1 CONDENSATE SPILL OF 670M3 OVER TEN DAYS FROM LOSS OF WELL CONTROL - STOCHASTIC MODEL 286 APPENDIX FIGURE 4 2 : SCENARIO 2 CONDENSATE SPILL OF 670M3 OVER TEN DAYS FROM LOSS OF WELL CONTROL TRAJECTORY TOWARDS UK COASTLINE 287 APPENDIX FIGURE 4 3 : SCENARIO 3 CONDENSATE SPILL OF 670M3 OVER TEN DAYS FROM LOSS OF WELL CONTROL TRAJECTORY TOWARDS CLOSEST INTERNATIONAL BOUNDARY 288 APPENDIX FIGURE 4 4 : SCENARIO 4 INSTANTANEOUS DIESEL SPILL OF 750M3 FROM LOSS OF RIG INVENTORY TRAJECTORY TOWARDS UK COASTLINE 289 APPENDIX FIGURE 4 5 : SCENARIO 5 INSTANTANEOUS DIESEL SPILL OF 750M3 FROM LOSS OF RIG INVENTORY TRAJECTORY TOWARDS CLOSEST INTERNATIONAL BOUNDARY 289 APPENDIX FIGURE 4-6 : SCENAR IO 6 INSTANTANEOUS DIESEL SPILL OF 750M3 FROM LOSS OF RIG INVENTORY TRAJECTORY TOWARDS CLOSEST INTERNAT IONAL BOUNDARY 291 APPENDIX FIGURE 6 1 : RISK ASSESSMENT FLOW CHART FOR NON-TRIVIAL DISTURBANCE 299 APPENDIX FIGURE 6 2 : RISK ASSESSMENT FLOW CHART FOR PHYSICAL INJURY 299 APPENDIX FIGURE 6 3 : M-WEIGHTING FUNCTIONS FOR LOW-, MID-, AND HIGH-FREQUENCY CETACEANS 300 CF00-00-EB-108-00001 Rev C1

Glossary A Analogue survey e.g., bathymetry, sonar imagery and shallow profiling. Technique of representing a sensor's input as amplitude modulated electrical signal (e.g., analogue profiles are output on sweep recorders as opposed to digital) Anode Appraisal Well Aspect (environmental) Positive electrode Phase of operations that immediately follows successful exploratory drilling. During appraisal, wells might be drilled to determine the size of the oil or gas field and how to develop it most efficiently. Element of an organisations activities, products or services that can interact with the environment B Backfill The replacement of excavated sediment into a trench Bacterioplankton Baseline Bathymetry The bacterial component of the plankton that drifts in the water column. The conditions existing before the commencement of dredging operations The measurement of the depth of the ocean floor from the water surface; the oceanic equivalent of topography Beam Trawl Trawl where the mouth of the net is held open by a metal beam up to 12 metres in length. The beam is mounted on trawl heads or skids, one at each side of the net. This gear is used primarily for flatfish Beaufort force Benthic Benthic ecology Berms Biodiversity Biogenic Biogeographic Empirical measure (scale of 0 to 12) for describing wind velocity based mainly on observed sea conditions established by Admiral Francis Beaufort (1774 to 1857). Living in the seabed or in seabed sediments The nature and distribution of organisms on the seabed Mound of dirt The range of species that comprise a particular community or habitat Chemicals or material produced by living organisms or biological processes Related to the geographical distribution of biodiversity over space and time C Carboniferous Period of the Palaeozoic Era occurring from 345 million to 280 million years ago Catch Per Unit Effort (CPUE) Cetaceans Climate change Conductor Cone Penetration Test (CPT) Consultees Measurement of the mass of fish caught for a given amount of energy and resources expended by a fishing fleet Whales and dolphins Refers to changes in long-term trends in the average climate, such as changes in average temperatures. It can refer to any change in climate over time, whether due to natural variability or as a result of human activity. Casing string that is usually put into the wellbore at the surface to stop the sides of the well falling in. Method of providing data for use in characterising subsurface marine sediments consisting of a steel cone that is hydraulically pushed into the ground. Sensors on the tip of the cone collect data to classify sediment type by measuring cone-tip pressure and friction. Those consulted as part of the Environmental Impact Assessment CF00-00-EB-108-00001 Rev C1

Copepods Crustacean Cuttings A group of small crustaceans of the Class Copepoda Shellfish such as crabs, lobsters and prawns Small pieces of rock that break away due to the action of the bit teeth. Cuttings are screened out of the liquid mud system at the shale shakers and are monitored for composition, size, shape, colour, texture, hydrocarbon content and other properties. D Decommissioning The process of closing down an operation. Demersal Development Devensian Directives Diversity dsac Dynamic positioning (DP) Organisms dwelling at or near the bottom of the sea. The phase of operations that occurs after exploration has proven successful, and before full-scale production. The newly discovered oil or gas field is assessed during an appraisal phase, a plan to fully and efficiently exploit it is created, and additional wells are usually drilled. Geological period approximately 48,000 to 12,000 years before present during which the latest ice age occurred. An instruction for an EU member state to introduce legislation The distribution and abundance of different kinds of plant and animal species and communities in a specified area Draft Special Area of Conservation an area that has been formally advised to UK government as suitable for SAC designation, but has not been formally approved by government. A computer controlled system to automatically maintain a vessel's position and heading by using her own propellers and thrusters. E EC Decisions Binding to those EU member states, specific commercial enterprises or social-economic groups it is directed to EC Opinions and Recommendations EC Regulations Echinoderm Echolocation Echosounding Effort Elasmobranch Environmental Impact Assessment (EIA) Environmental Statement (ES) Epifauna European Commission Not binding on EU member states but are meant to encourage desirable practices A binding law applicable to all EU member states A phylum of marine mammals (including sea stars, sea urchins, sea cucumbers and feather stars) Used by animals to orientate, navigate, and find food it is the detection of the position, distance and size of an object by means of reflected sound. The action or process of sounding or ascertaining the depth of water or of an object below a ship by measuring the time taken for a transmitted sound-signal to return as an echo. Measure of input extended by people to catch fish (expressed in days fished). Cartilaginous fish such as sharks, skates and rays The critical appraisal of the likely effects of a proposed project, activity, or policy on the environment, both positive and negative. A means of submitting to the regulatory authority, statutory consultees, non government organisations and the wider public, the findings of an environmental assessment. Organisms living on the seabed surface Executive branch of the European Union, responsible for proposing legislation F Fauna Animals, both invertebrates and vertebrates Flaring The burning of unwanted gas through a pipe. Flaring is a means of disposal used when there is no way to transport the gas to market and the operator cannot use the gas for another purpose CF00-00-EB-108-00001 Rev C1

Flora Footprint Frac / fraccing Plant life The extent on an environmental effect A stimulation treatment routinely performed on oil and gas wells in lowpermeability reservoirs. Specially engineered fluids are pumped at high pressure and rate to crack or fracture the formation. G Geophysical The study of the earth by quantitative physical methods, especially by seismic reflection and refraction, gravity, magnetic, electrical, electromagnetic, and radioactivity methods Geotechnical Glaciation Greenhouse gas Grey Water The study of soil and rock below the ground to determine its properties The process of covering the earth with glaciers or masses of ice The gases present in the earth's atmosphere which reduce the loss of heat into space and therefore contribute to global temperatures through the greenhouse effect. Non-industrial wastewater generated from domestic processes such as washing dishes, laundry and bathing H Haul-out site A site where seals come on to shore or on to a sandbank Holocene Hydrotest I ICES rectangles Statistical divisions of the sea. Impact (environmental) Infauna A geological period, which began approximately 9600 BC and continues to the present The process of pumping water through a pipeline at a higher pressure level than is normally used when transporting petroleum to confirm the continued safe operation of the pipeline, ensuring that it's free of any defects. Any change to the environment, whether adverse or beneficial, wholly or partially resulting from an organisation's activities, products or services. Organisms that live within the sediment J Jack-up rig A self-contained drilling unit on a floating barge fitted with long support legs that can be raised or lowered independently of each other. Jetting Trench digging by use of high-pressure water. K Kilometre Point (KP) A general term for the distance along a route from a fixed reference point. Kingfisher Bulletins L Landings Data Reported fish landed at ports Leak-testing Leman est Astronomical Tide (LAT) Fortnightly bulletin providing free safety information to all sea users The determination of the location of a leak in a pipeline. A sandstone formation, which forms part of the unfossiliferous Rotliegend sediments in the Jupiter Fields The lowest level that can be expected to occur under average meteorological conditions and under any combination of astronomical conditions. M Median Line Offshore international boundaries Mesolithic Mollusca A period in the development of human technology between the Palaeolithic and Neolithic periods of the Stone Age A large group of animals including snails, bivalves and squid N Notices to Mariners Information issued from a number of different sources, such as the UK Hydrographic Office, Trinity House or Local Harbour Authorities and may contain a variety of information such as chart updates, changes in buoyage, prior warning of activities such as dredging, exclusion zones, harbour closures etc. CF00-00-EB-108-00001 Rev C1

Nursery An area or region where high densities of juvenile fish species congregate O OSPAR Instrument guiding international cooperation on the protection of the marine environment of the North-East Atlantic P P50 The 50% probability of something occurring. Pelagic Permian Petrogenic Phytoplankton Phytoplankton Bloom Piggy-backed Pinnipeds Pleistocene Polychaete Potential Annex I Habitat (PAIH) Precautionary principle psac Pyrogenic Relating to or occurring or living in or frequenting the open ocean Geological period within the Palaeozoic era 300 to 251 million years before present A contaminant produced from unburned petroleum products Microscopic floating plants that exist within the water column High concentration of phytoplankton in an area, caused by increased reproduction To lay two pipelines together in the same trench - the smaller on top of the larger pipeline. Seals The epoch from 1.8 million to 10,000 years BP covering the world's recent period of repeated glaciations. A group of marine worms with numerous bristle like chaete Habitat (as defined in Annex I of the EU Habitats Directive) identified in offshore areas to be put forward to the government for protection as part of the Natura 2000 in UK offshore waters programme. States that where there is a lack of scientific data, this should not be used as a reason for postponing measures to prevent environmental degradation. Possible Special Area of Conservation an area that has been formally advised to UK government as suitable for SAC designation, but has not been submitted to the European Commission Produced under conditions involving intense heat Q Quaternary Geological epoch comprising the Pleistocene and Holocene R Ramsar The Convention on Wetlands signed in Ramsar, Iran in 1971 is an intergovernmental treaty that provides the framework for national action and international cooperation for conservation and wise use of wetlands and their resources. Reservoir Rig Riser Riverine Subsurface body of rock having sufficient porosity and permeability to store and transmit fluids. Sedimentary rocks are the most common reservoir rocks because they have more porosity than most igneous and metamorphic rocks and form under temperature conditions at which hydrocarbons can be preserved. A drilling unit that is not permanently fixed to the seabed, e.g. a drillship, a semi-submersible or a jack-up unit. Also means the derrick and its associated machinery. The pipe which connects a rig or platform to a subsea wellhead or subsea pipeline during drilling or production operations to take mud returns to the surface. Relating to systems that are influenced by a river S Scour Removal of underwater material by waves or currents Seismic Pertaining to waves of elastic energy, such as that transmitted by P-waves and S-waves, in the frequency range of approximately 1 to 100 Hz, used to interpret the composition, fluid content, extent and geometry of rocks in the subsurface. CF00-00-EB-108-00001 Rev C1

Semi-diurnal Shellfish Side-Scan Sonar (SSS) Spawning Species Spud can Stakeholder Strategic Environmental Assessment Occurring once every 12 hours An aquatic animal, such as a mollusc or crustacean, that has a shell or shell-like exoskeleton Sonar tool used for mapping the seabed Reproductive activity of fish; the act of releasing eggs into the water by female fish for fertilization by male fish. A group of related organisms having common characteristics and capable of interbreeding. A shallow conical underside footing on the bottom of the jack-up rigs legs An individual or group with an interest in the outcome of a project A system of incorporating environmental considerations into policies, plans and programmes. T Taxa Categories in the biological classification system for all living organisms (i.e., kingdom, phylum, class, order, family, genus, species). Tie-in Trenching An operation in pipeline construction in which two sections of line are connected; a loop tied into the main line. The process of cutting a narrow excavation into the ground. The earth removed is thrown out on either side. In the context of this document it is used to bury pipelines. U Umbilical A conduit through which hydraulic fluids, chemicals, power and data are supplied Univariate Describes a collection of procedures which involve observation and analysis of one statistical variable V Venting Releasing gas or gases from the well or pipelines Vibrocore Acquisition of seabed sediment cores using a vibrating steel tube which penetrates the seabed to a particular depth W Well Head The surface termination of a wellbore that incorporates facilities for installing casing hangers during the well construction phase. The wellhead also incorporates a means of hanging the production tubing and installing the Christmas tree and surface flow-control facilities in preparation for the production phase of the well. Well-test A test whereby the nature and quantity of the formation fluids in a possible oil- or gas-bearing stratum are determined by allowing them to flow to the surface through the drill string under carefully controlled conditions. X Xmas tree An array of pipes and valves fitted to a wellhead to control the flow of produced or injected fluid. Z Zooplankton Small aquatic animals that float or weakly swim within the water column. Generally longer than 153 µm, up to about 5,000 µm (5 mm). CF00-00-EB-108-00001 Rev C1

ACRONYMS AND UNITS Units barg Bar gauge pressure bbl/d Barrel per day bbls Barrels Bscf Billion standard cubic feet cm Centimetre m3 Cubic metre m3km -1 Cubic metres per kilometre db Decibel Hz Hertz hr Hour " Inch khz Kilo hertz kw Kilo watt kg Kilogram km Kilometre < Less than MW Mega Watt MW(th) Mega watt thermal m Metre ms -1 µpa µgm -3 µg.g -1 µgl -1 Metres per second Micro pascal Microgram per cubic metre Microgram per gram Microgram per litre µm Micrometres mgl -1 Milligram per litre mm Millimetre MMscf Million standard cubic feet MMscfd Million standard cubic feet per day > More than ngl -1 Nano gram per litre ppb Parts per billion % per hundred km 2 Square kilometre m 2 Square metre A AET Apparent effects threshold B BAT Best available technique BGS British Geological Survey CF00-00-EB-108-00001 Rev C1

BMAPA British Marine Aggregate Producers Association BMS Business Management System BP Before present BRC Background reference concentration BSI British Standards Institute C CBD Convention on Biological Diversity Cd Cadmium CEFAS Centre for Environment, Fisheries and Aquaculture Science CH4 Methane CLG Department for Communities and Local Government CMS Caister Murdoch System CNS Central North Sea CO Carbon monoxide CO2 Carbon dioxide CPR Continuous plankton recorder CPT Cone penetration test CPUE Cost per unit effort Cr Chromium Cu Copper D DECC Department of Energy and Climate Change Defra Department for Environment, Food and Rural Affairs DP Dynamic positioning dsac draft Special Area of Conservation DTI Department of Trade and Industry (now DECC) E e.g. For example EC European Commission EIA Environmental Impact Assessment EMS Environmental Management System EMT Emergency Management Team EPS European Protected Species ES Environmental Statement ETS Esmond Transportation System EU European Union EU ETS European Union emission trading system F FAO Food and Agricultural Organisation FDP Field development plan FLO Fisheries Liaison Officer FRS Fisheries Research Service (now part of Marine Scotland) G GDF Gaz de France Britain (now part of GDF SUEZ E&P UK) GESAMP Joint Group of Experts on the Scientific Aspects of Marine Environment Protection CF00-00-EB-108-00001 Rev C1

GIS Geographical information system H Hg Mercury HMCG Her Majesty's Coast Guard HQ Hazard quotient HS&E Health, safety and environment HSE Health and Safety Executive I IBA Important bird area ICES International Council for the Exploration of the Sea IMO International Maritime Organisation IMT Incident Management Team IPPC Integrated Pollution Prevention and Control J JNCC Joint Nature Conservation Committee K KP Kilometre point L LAT est Astronomical Tide M MCA Maritime and Coastguard Agency MCAA Marine and Coastal Access Act MEG Monoethylene glycol MMO Marine mammal observer or Marine Management Organisation N N2O Nitrous oxide NO2 Nitrogen dioxide NAEI National Atmospheric Emissions Inventory NFFO National Federation of Fishermen's Organisations Ni Nickel NNS Northern North Sea NOEC No observed effect concentration NOx Oxides of nitrogen NPAI Not permanently attended installation NTS National Transmission System NUI Normally unmanned installation O OBM Oil based mud OCNS Offshore Chemical Notification Scheme OCR Offshore Chemical (Amendment) Regulations 2011 OGUK Oil and Gas UK OIW Oil in water OPEP Oil pollution emergency plan OSPAR Oslo Paris Convention OSPRAG Oil Spill Prevention and Response Advisory Group OSR Oil Spill Response P PAH Poly aromatic hydrocarbons PAIH Potential Annex I Habitat CF00-00-EB-108-00001 Rev C1

Pb PAM PCB PEXA PIG PLEM PLO or PLONOR PON psac pspa PTS PU PW PWA PWRI Lead Passive acoustic monitoring Polychlorinated biphenyls Practice and exercise area Pipeline inspection gauge Pipeline end manifold Poses little or no risk Petroleum Operations Notice possible Special Area of Conservation possible Special Protection Area Permanent shift in hearing threshold Process and utilities (platform) Produced water Pipeline works authorisation Produced water re-injection Q QHSE Quality, Health, Safety and Environment QHSEMS Quality, Health, Safety and Environment Management System R Ramsar The Convention on Wetlands signed in Ramsar, Iran 1972 REACH RIA ro-ro ROV RYA Registration, Evaluation, Authorisation and Restriction of Chemicals Regulatory impact assessment Roll on - roll off facility Remotely operated vehicle Royal Yachting Association S SAC Special Area of Conservation SCANS II SEA SEL SL SNS SO2 SOPEP SoS SOx SPA SPL spp. SSIV SSS SUB Small Cetaceans in the European Atlantic and North Sea II Strategic environmental assessment Sound exposure level Source level Southern North Sea Sulphur dioxide Shipboard oil pollution emergency plan Secretary of State Oxides of sulphur Special Protection Area Sound pressure level Species Subsea safety isolation valve Side-scan sonar Substitution T TEG Triethylene glycol CF00-00-EB-108-00001 Rev C1

THC Total hydrocarbons U UK United Kingdom UK BAP UK Biodiversity Action Plan UKCIP UK Climate Impact Programme UKCS United Kingdom Continental Shelf UKOOA United Kingdom Offshore Operators Association (now Oil and Gas UK) UNFCCC United Nations Framework Convention on Climate Change UQ Utilities and living quarters (platform) V VHF Very high frequency (radio) VOC Volatile organic compounds W WBM Water based mud Z Zn Zinc CF00-00-EB-108-00001 Rev C1

1.0 INTRODUCTION proposes to develop the Cygnus gas field in the UK Southern North Sea (SNS) in Blocks 44/12a and 44/11a. The field will consist of two platforms, Cygnus A and Cygnus B tied back to the existing Esmond Transportation System (ETS) pipeline export system via a new gas export pipeline. Gas export to the UK mainline will be via the ETS pipeline which terminates onshore at Bacton. The field will target the Carboniferous Westphalian and Permian Leman formations. This Environmental Statement (ES) has been prepared on behalf of GDF SUEZ E&P UK to meet the requirements of UK legislation and in support of the Plan (FDP). It covers: The Cygnus Alpha (Cygnus A) hub, a permanently manned main platform with central production, processing and accommodation facilities The Cygnus Bravo (Cygnus B) satellite wellhead platform, a not permanently attended installation (NPAI) tied back to the Cygnus A central facility The drilling of ten horizontal wells A circa. 51km 24-inch export pipeline tied in to the existing ETS pipeline A 5.9km 12-inch infield pipeline and umbilical between Cygnus A and Cygnus B Associated subsea infrastructure Operation and production of the field for an expected 35 years 1.1 THE DEVELOPER is a wholly owned oil and gas exploration and production subsidiary of the GDF SUEZ Group. GDF SUEZ E&P UK is an established exploration and production operator in the UK, active in the SNS, Central North Sea and West of Shetland region. In the UK GDF SUEZ E&P UK holds 46 seaward production licences 1 (16 as an operator) and 15 producing assets (1 as the operator - Minke Field). A total of 9 million barrels of oil equivalent (boe) are produced by GDF SUEZ E&P UK per year and the proportion of operated production is expected to rise to 50% by 2013 (www.vadvert.co.uk 2011). GDF SUEZ E&P UK was awarded seven new oil and gas licenses in the 26th UK Licensing Round, five of which are operated licenses. The UK forms a significant share of the global GDF SUEZ business and makes a significant contribution to the Group s targets in securing gas supplies through production. As such GDF SUEZ E&P UK is committed to the oil and gas industry in the UK and to developing its existing portfolio. The development of the Cygnus field fits within this target. GDF SUEZ E&P UK has a 38.75% interest in the Cygnus Field (Licence P1055) and will act as the operator on behalf of the other owners. GDF SUEZ E&P UK s equity owners are Centrica (48.75%) and Bayerngas (12.5%) (GDF SUEZ E&P UK 2011a). 1.2 PROJECT OVERVIEW The Cygnus field development is a medium-sized gas development located within the already extensively developed SNS gas basin. 1.2.1 Field History The Cygnus field is a composite structure encompassing a series of tilted fault blocks. Figure 1-1. It was discovered by the Marathon exploration / appraisal wells 44/12-1 in 1988 and 44/11-2 in 1989. These wells were not tested. In 2006, GDF SUEZ E&P UK drilled a vertical exploration well (44/12-2) to target fault block 1. The Permian age, Rotliegendes er Leman sandstone was successfully tested and gas bearing Carboniferous Westphalian formations were also encountered but not tested. In 2009, GDF SUEZ E&P UK drilled two appraisal wells, 44/12a-3 that tested a 1 license to search and bore for and get petroleum CF00-00-EB-108-00001 Rev C1 Page 1 of 300

gas-bearing Carboniferous interval and 44/12a-4 that tested good quality gas-bearing Leman Sandstone. In 2010, two additional appraisal wells 44/11a-4 and 44/12a-5 were drilled and tested. These also encountered good quality gas bearing Leman Sandstone (GDF SUEZ E&P UK 2011a). The field contains dry gas with a low condensate-gas ratio i.e., less than 1 barrel of condensate per million standard cubic feet of gas (0.16m 3 : 28,319m 3 ). The proposed development aims to target blocks 1, 2a, 2b, 3 and 4 (Figure 1-1). Figure 1-1 : Cygnus field structure showing composite fault blocks 1.2.2 Location The project is located in United Kingdom continental shelf (UKCS) Blocks 44/11a and 44/12a of the SNS, approximately 155km north-east of the north Norfolk (UK) coastline and 35km west of the UK/Netherlands median line. The development is within the Dogger Bank candidate Special Area of Conservation (csac). The boundaries of the csac lie 40km to the east and 35km to the south of the platforms. The export pipeline passes through the csac to the boundary 40km to the south-west of Cygnus A and extends 10km beyond this boundary. The location of the project is shown in Figure 1-2 and the co-ordinates are given in Table 1-1 below. 1.2.3 Schedule Construction activities will commence in April 2013 with first gas at Cygnus A anticipated for November 2014. First gas at Cygnus B is expected in March 2015. Construction will be phased into four key stages which are detailed in Section 5.1 and outlined below. Stage 1: 2013 campaign this involves installation of the Cygnus A wellhead platform (W), WYE Structure, subsea safety isolation valve (SSIV) structure, as well as laying and trenching the 24 pipeline and ETS pipeline tie-in during the Tyne/Trent/Bacton shutdown. Stage 2: 2014 campaign - the remaining Cygnus A Complex (processing and utilities (PU) Platform, accommodation and utilities (QU) Platform and bridges), will be installed. CF00-00-EB-108-00001 Rev C1 Page 2 of 300

Stage 3: between 2014 and 2016 - Cygnus B satellite platform and both the intra-field pipeline and umbilical will be installed. Stage 4: between 2015 and 2016 installation of compression module and drilling of final well at Cygnus A. Development drilling is expected to run from May 2013 to September 2016. Table 1-1: Project co-ordinates Structure Easting (E) Northing (N) Latitude (N) Longitude (E) Cygnus A Hub Production Platform Cygnus B - Satellite Wellhead Platform 454 180.58 6 047 239.45 54 34' 09.89" 02 17' 28.74" 448 685.00 6 049 512.00 54 35' 21.50" 02 12' 21.35" SSIV Manifold 454 136.64 6 047 324.03 54 34' 12.61" 02 17' 26.25" Wye Manifold 413 952.19 6 017 974.14 54 18' 04.45" 01 40' 39.89" Export pipeline tie-in point to the ETS pipeline 413 904.28 6 017 978.07 54 18' 04.55" 01 40' 37.24" Datum: ED50 UTM Zone 31N, Central Meridian 3 East CF00-00-EB-108-00001 Rev C1 Page 3 of 300

0 0' 1 0'E 2 0'E 55 0'N Cygnus B NPAI Cygnus A Hub 55 0'N ETS tie-in 54 30'N 54 30'N 54 0'N Flamborough Head 54 0'N 53 30'N 53 30'N Theddlethorpe 0 0' 1 0'E 2 0'E Legend Proposed project development Cygnus A Hub Environmental Statement Figure 1-2: Project Location Cygnus B NPAI Cygnus export pipeline Intrafield pipeline ETS tie-in Land UKCS Licence Block Median Line Date Projection Spheroid Datum Data Source File Reference Wednesday, August 31, 2011 09:23:20 UTM Zone 31N International 1924 ED 50 GEBCO, JNCC, UK Deal J:\P951\Mxd\O_Cygnus_ES\Final_31Aug2011\ Figure 1-2 Project Location.mxd Terminal Other Platforms Existing Pipelines Checked Produced By Reviewed By Emma White Anna Farley Hydrocarbon Field candidate SACs <20m water depth NOTE: Not to be used for navigation km 0 5 10 20 30 40 Metoc Ltd, 2011. All rights reserved.

1.2.4 Construction The Cygnus field will comprise two drilling centres: Cygnus A to develop the field in the east; and Cygnus B to develop the field in the west. The Cygnus A Hub will comprise a central permanently manned installation with production, dehydration and compression facilities to support the whole Cygnus development. It will consist of three bridge linked platforms (wellhead, PU and QU) with a compression module added to the processing & utilities platform at a later date. A new 51km 24-inch pipeline will export processed gas from the platform to a new manifold tie-in point on the existing ETS pipeline. It is proposed that five wells will be drilled from Cygnus A (Figure 1-1). It is possible that all development wells will be flared for 24 hours to clean-up the wellbore and test the reservoir. The Cygnus B satellite (Figure 1-1) will develop outlying field targets which cannot be reached from wells on the hub facility. Located approximately 5.9km west north-west (292 ) of Cygnus A, it will be a NPAI wellhead platform from which a further five wells will be drilled. Again it is possible that all production wells will be flared for the purposes of clean-up and testing. The NPAI will be tied back to the Cygnus A central facility via a new 12-inch infield gas production pipeline and umbilcal line. As mentioned in Section 1.2.3 above, construction will progress in four key stages: Stage 1 - The ETS pipeline tie-in subsea infrastructure will be installed and fixed to the seabed by piling. The Cygnus A wellhead platform will be installed with the jacket fixed to the seabed by piles. The export pipeline will be laid and trenched using a DP (dynamic positioning) vessel or anchor laybarge. An SSIV manifold will be installed at the extremity of the export pipeline within the Cygnus 500m zone and tied into the PU Platform export riser. The spools will be protected from dropped objects by concrete mattresses. The export pipeline will cross two pipelines, Cavendish to Murdoch and Tyne to Trent. The pipelines at the crossing locations will be protected by the installation of concrete mattresses to afford the correct pipeline to pipeline separation in accordance with the proposed Crossing Agreements. The crossings themselves will be afforded protection from fishing interaction by rock placement. Development drilling will commence at Cygnus A, which will include pressure fracturing. It is anticipated that this will only be required for three wells. Only four of the five wells will be drilled during this stage. Drilling will be from a jack-up rig cantilevered over the wellhead platform. Stage 2 - Cygnus A Hub PU platform and QU platform will be installed and fixed to the seabed using piles. The platforms will be connected to the wellhead platform with bridges. Stage 3 The Cygnus B NPAI will be installed with the jacket pile driven into the seabed. The 12- inch intra-field pipeline will be laid and trenched using either a DP vessel or anchor lay barge and a control umbilical will be laid in a separate trench. Drilling of five wells at Cygnus B will commence with the jack-up rig cantilevered over the Cygnus B satellite wellhead platform. Stage 4 - During the final stage of construction, the final well will be drilled at the Cygnus A platform and the Cygnus A Hub compression module will be installed on the PU Platform. 1.2.5 Production First gas is currently anticipated to be achieved in November 2014. The Cygnus facilities are currently designed to deliver a maximum flow of 250 MMscfd (million standard cubic feet per day) (7.1 million m 3 /d) of dry sweet gas to the export pipeline to Bacton along with up to 750 bpd (barrels per day) (47.7 m 3 /d) of dry condensate. The initial export rate will be limited to 190 MMscfd (5.4 million m 3 /d) rising to 250 MMscfd (7.1 million m 3 /d) in 2016. Reservoir productivity indicates that gas can flow under natural reservoir pressure (i.e., no artificial lift is required) potentially for a few years. Therefore installation of the compression module at Cygnus A will be deferred for approximately 1 year dependant on reservoir performance. Dried fluids will be exported from the Cygnus central production facility, dehydrated to at least 6 lbs water per mmscf of gas. To mitigate corrosion issues in the ETS pipeline it may be necessary to increase the water removal specifications at a later date. Up to 150 MMscfd (4.2 million m 3 /d) of wet gas and 525bpd of condensate will be produced from the Cygnus B NPAI. Hydrate formation will be inhibited using MEG provided via the umbilical from Cygnus A. Communications between Cygnus A and B will be via the control umbilical and by line of sight. Cygnus A will have two dual fuel turbine driven power generators which will generate approximately 3 MW and provide the necessary power requirements for both platforms CF00-00-EB-108-00001 Rev C1 Page 5 of 300

The only significant gas venting will occur from Cygnus B for planned inspections. At Cygnus A under normal operating conditions small amounts of gas will be liberated from the produced water degasser and the MEG/TEG reboilers. Additionally Cygnus A will have a continuous flare lit to dispose of any gas from emergency depressurisation of equipment. Produced water will be separated on Cygnus A and B. Both platforms will be equipped with coalescing vessels and degassers to minimise oil in water concentrations before discharge to sea. Online oil in water measurement will be backed up by sampling on a regular basis at Cygnus A and on an opportunity basis at Cygnus B. At each of the wells at Cygnus A where pressure fracturing is planned, proppant (which is graded sand) will be injected into the reservoir. Each of these wells is expected to return graded sand and water as a result of the fracture process for the first three months of production. Sand and water will be sampled for reservoir hydrocarbon contamination, cleaned and discharged to sea. 1.2.5.1 Decommissioning Depending on reservoir performance and economic variables, it is expected that production will cease between 2024 and 2038 assuming that no further developments are tied back to the facilities. Decommissioning will be carried out in accordance with all applicable UK government and international legislation and practices in force at the end of field life and a Consent for Cessation of Production will be sought in advance. The development plan is based on the following assumptions: Plug and abandon all wells Removal of the conductors to below the mud line Removal of platforms and subsea manifolds Trenched and buried pipelines left in-situ in a safe condition Third party confirmation of seabed clearance These requirements were considered in the design of the facilities and during project planning. 1.3 FORMAT OF THE ENVIRONMENTAL STATEMENT This ES is divided into the principal sections outlined in Table 1-2. Table 1-2 : Structure of this ES Section Title Content - Non-Technical Summary The aim of the non-technical summary is to enable communication with those unfamiliar with the environmental impact assessment (EIA) process and terminology by summarising the key findings of the ES document in simple terms. 1 Introduction An introduction describing the developer and summarising the project. 2 Institutional, Policy and Regulatory Frameworks 3 Project Justification A description of the legislative frameworks which govern the project and the EIA. This section justifies why the project is preferable to alternative options elsewhere. 4 EIA Methodology A description of the process followed when conducting the EIA. 5 Project Description A description of the project in terms of the activities that will be undertaken during the construction, operation and decommissioning stages of the project. 6 Project Footprint A quantitative description of the emissions to air, sea and ground from the construction, operation and decommissioning stages of the project. CF00-00-EB-108-00001 Rev C1 Page 6 of 300

Section Title Content 7 Accidental Events This section describes the types of accidental events that could occur during construction and production and presents oil spill modelling results for worst case oil spill scenarios. 8 Impacts on Physical Environment 9 Impacts on Biological Environment 10 Impacts on Human Environment 11 Cumulative and Indirect Impacts 12 Environmental Management 13 Conclusions 14 References Appendix 1 Appendix 2 Appendix 3 Appendix 4 Appendix 5 Appendix 6 Key policy, law and guidelines Environmental Impact Assessment Chemical Summary - Wells Oil Spill Modelling Seasonal Wind Roses 1.4 ES AVAILABILITY JNCC Risk Assessment Flow Charts These sections describe the physical, biological and human baseline environment in the project area and identify those activities of the project that may interact with environmental receptors. They evaluate and specify project impacts upon the individual receptors, describing them quantitatively wherever possible (in some cases only a qualitative assessment is possible) and in each case the level of significance has been determined. Mitigation measures to avoid, reduce or remedy the effects identified in the impact assessment are outlined. This section considers cumulative impacts where the project contributes to impacts occurring from other activities or processes. This section describes the GDF SUEZ E&P UK corporate and project specific management system outlining how GDF SUEZ E&P UK will manage health, safety and environment activities arising from the project. Further information on the policy, law and guidelines considered during the EIA This section provides the full environmental impact assessment undertaken for the development. The section is divided into Construction, Production and Accidental Events. List of typical chemicals to be used during drilling This section provides a more detailed assessment of the potential impacts from hydrocarbon releases in line with guidance released to industry on 23 December 2010. Annual and monthly wind roses for the development area Flow charts used to support the EIA of the potential impact of noise A digital version or hard copy of the ES is available on request from: Dr Trevor Yip-Hoi 40 Holburn Viaduct London, EC1N 2PB United Kingdom Email: trevor.yip-hoi@gdfsuezep.co.uk CF00-00-EB-108-00001 Rev C1 Page 7 of 300

2.0 INSTITUTIONAL POLICY AND REGULATORY FRAMEWORKS 2.1 INTERNATIONAL CONVENTIONS, EC LAW, UK LAW AND POLICIES Offshore oil and gas developments are governed by a collection of international, European Commission (EC) and UK laws, policies and guidelines. These laws, policies and guidelines are implemented through various institutional frameworks. The management goals and objectives that an environmental assessment may aim to achieve are governed by these laws/policies and institutional frameworks. Although not an exhaustive list, Table 2-1 outlines the main policies, laws and guidelines relevant to this project and considered in this ES. Further details of each policy, law and guideline are provided in Appendix 1. Table 2-1 : Summary of international conventions, EC law and UK law and policy relevant to the project UK Policy and Guidelines International Conventions EC Law Meeting the Energy Challenge 2007 UK Carbon Transition Plan 2009 UK Marine Policy Statement UK Biodiversity Action Plan (UKBAP) Convention for the Protection of the Marine Environment of the North East Atlantic (Oslo Paris Convention (OSPAR) Convention) 1992 Convention on Biological Diversity (CBD) 1992 United Nations Framework Convention on Climate Change (1994) Convention on Environmental Impact Assessment in a Transboundary Context (Espoo) 1991 Council Directive 97/11/EC (EIA Directive) Council Directive 2003/35/EC (Public Participation Directive) Council Directive 2001/42/EC (SEA Directive) Council Directive 92/43/EC (Habitats Directive) Council Directive 79/409/EC (Birds Directive) Council Directive 2008/1/EC (Integrated Pollution Prevention and Control (IPPC) Directive) Council Directive 2003/87/EC (EU Emissions Trading Scheme (EU ETS) Directive) Council Regulation 1907/2006 Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) OSPAR Recommendation 2010/5 on the assessment of environmental impacts on threatened and/or declining species UK Law Petroleum Act 1998 Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) (Amendment) Regulations 2007 Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 (amended in 2007) Offshore Marine Conservation (Natural Habitats, &c.) Regulations 2007 (as amended in 2009 and 2010) Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2011 Offshore Chemical (Amendment) Regulations 2011 Merchant Shipping (Oil Pollution Preparedness, Response Co-operation Convention) Regulations 1998 The Offshore Installations (Emergency Pollution Control) Regulations 2002. Marine and Coastal Access Act (MCAA) 2009 CF00-00-EB-108-00001 Rev C1 Page 8 of 300

Energy Act 2008 2.2 SEA AND EIA GUIDELINES The Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008 The Greenhouse Gas Emissions Trading Scheme Regulation 2005 (as amended) The Offshore Combustion Installations (Prevention and Control of Pollution) (Amendment) Regulations 2007 The DECC have issued guidance notes regarding the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) (Amendment) Regulations 2007, providing details of the required contents of an ES. This ES takes into account this latest guidance (DECC 2009a). In addition, the DECC released a statement in a letter to industry (23 December 2010) stating that the ES assessment of potential impacts from hydrocarbon releases must be extended to match the scope of the recently amended OPEP guidelines. The EIA process is designed to consider the potential impacts from an individual project, ignoring those from other activities in the area. Although consideration is now being given to cumulative impacts in EIA this is still project specific. As a result of the limitations of the EIA process there is now a push towards using EIA at a more strategic stage of the industry development phase. SEAs consider environmental objectives at policy and planning stages, provide a common basis for EIA preparation, and ensures that total activity level in one region does not impose unacceptable regional environmental impacts. In 2001 the EC adopted a Directive on the assessment of the effects of certain plans and programmes on the environment 2001/42/EC (SEA Directive). Although the UK have yet to formally implement this Directive, the DECC has produced a series of SEAs for regions of the UKCS. This project lies within SEA region 2. Once SEAs were completed for all regions of the UKCS an Offshore Energy SEA (OESEA) was undertaken in 2008/2009 to inform further seaward rounds of oil and gas licensing, future licensing for the underground storage of combustible gas in depleted and other offshore oil and/or gas fields and further rounds of offshore wind farm leasing. This OESEA was updated with amendments and was reissued in 2011. The technical reports and recommendations made in all of these SEAs were used to inform this EIA. 2.3 UK INSTITUTIONAL FRAMEWORK Secretary of State (SoS) The ES review and approval process culminates in an approval from the SoS under the Petroleum Act 1998. The SoS is also the focal point for appeals to decisions and leads the various teams in the DECC. Department of Energy and Climate Change (DECC) Administers the Petroleum Act 1998 under which project consents are given. They are the principal environmental regulator for the offshore oil and gas industry and are responsible for implementation of the EIA Regulations. They also represent the UK as a Regulatory Authority at OSPAR. Department for Environment, Food and Rural Affairs (Defra) Responsible for implementation of Government programmes for the protection of the environment, food (including fisheries) and rural affairs. At the European and international level Defra represent the UKs interests at OSPAR. The department provides advice to the DECC on a range of subjects including: environmental statements, the interactions between fisheries and offshore operations, offshore construction and drilling activities, marine pollution and chemical use and discharge. In England many of the advisory responsibilities for the offshore oil and gas industry are delegated to the Centre for Environment, Fisheries and Aquaculture Science (CEFAS). Joint Nature Conservation Committee (JNCC) Responsible for promoting nature conservation at UK and international levels. They are the main government and industry advisor on offshore sensitivities with respect to seabirds and cetaceans. Amongst other roles they advise the DECC on ESs and are the body responsible for identification and recommendation on offshore conservation areas under the EC Habitat Directive. Centre for Environment, Fisheries and Aquaculture Science (CEFAS) An Executive Agency of Defra they are a scientific research and advisory centre for fisheries management, CF00-00-EB-108-00001 Rev C1 Page 9 of 300

environmental protection and aquaculture. Amongst other roles they advise the DECC on the Offshore Chemical (Amendment) Regulations 2011 and impacts on fish and fisheries. 2.4 GDF SUEZ E&P UK CORPORATE POLICY GDF SUEZ E&P UK believe that all incidents are preventable. Their goal is to prevent adverse health, safety and environmental (HSE) impacts on employees, contractors, public, stakeholders and the environment. The company s Health, Safety and Environmental Policy, endorsed by the Senior Vice-President and Managing Director, include commitments to comply with local HSE regulations, integrate HSE into the management of all activities, preserve the environment, to continually improve HSE performance and communicate HSE performance to all their stakeholders. The policy is reviewed annually by the environmental management team and communicated to all persons working on behalf of the organisation. To best achieve these objectives GDF SUEZ E&P UK maintains a comprehensive HSE and quality management system, details of which are provided in Section 12. The HS&E and quality policies are provided in Figures 2-1 and 2-2 below. CF00-00-EB-108-00001 Rev C1 Page 10 of 300

Health, Safety and Environment Policy As Senior Vice-President of GDF SUEZ Exploration & Production and Managing Director, we adhere to GDF SUEZ Corporate values and consider the protection of Health, Safety and Environment (HSE) as a core value beneficial to all E&P activities. For all our activities, we believe that all incidents are preventable, and our goal is to prevent adverse HSE impacts on employees, contractors, public, our stakeholders and the environment. GDF SUEZ Exploration & Production Management is committed to: Comply with local HSE regulations, Integrate HSE into the management of all activities, Create a safe and healthy workplace and preserve the environment, Be engaged with employees and contractors to manage operations according to GDF SUEZ E&P HSE requirements, Continuously monitor and improve our HSE performance, and Communicate our HSE performance to all stakeholders. GDF SUEZ E&P Management shall demonstrate visible HSE leadership and shall provide adequate resources to ensure the highest level of HSE culture and competence in our organisation. Every employee shall comply with this policy and be proactive in safeguarding HSE for herself/himself and for others. We are committed to the application of this policy at all GDF SUEZ E&P levels to reach our milestone in HSE performance which is to be amongst the upper quartile of the E&P companies operating in Europe with regards to the references of the International Association of Oil and Gas Producers. Didier Holleaux Senior Vice-President GDF SUEZ E&P Jean-Claude Perdigues Managing Director September 2010

The right people, doing the right things, in the right way, at the right time Quality Policy Our goal is to consistently deliver stakeholder value by achieving the highest standards of quality assurance and control across all aspects of our business. Our long-term vision and success depends on our ability to deliver operational excellence fully aligned with our HSE policy and business management systems. GDF SUEZ E&P UK shall achieve this by: Commitment and Compliance - Visibly demonstrating enthusiasm for the business and commitment to our policies; complying with relevant regulatory requirements and GDF SUEZ E&P policies and processes in all of our business activities. Strong Leadership - Leading by example, and being accountable for the effectiveness of the business processes and resources. Effective Resources - Cohesively using personnel, contractors and suppliers with the necessary competence, in a shared spirit of teamwork. Stakeholder Engagement - Developing stakeholder relationships, understanding and meeting their expectations and creating value for all. Communication and Planning - Sharing information with the right people, encouraging feedback and taking the necessary timely actions to achieve superior performance and continual improvement. GDF SUEZ E&P UK shall maintain a Business Management System incorporating ISO 9001: 2008 requirements, which supports this quality policy and encourages a culture of continual process improvement throughout the business. Through implementation of this policy, all personnel working on behalf of GDF SUEZ E&P UK shall be required to organise, define, plan, execute, control and verify the quality of their work in accordance with the approved Business Management System. Jean-Claude Perdigues Managing Director May 2011 18/05/2011 GaS UK-POL-00002 1

3.0 PROJECT JUSTIFICATION AND ALTERNATIVES 3.1 PROJECT JUSTIFICATION Internationally and nationally, energy demand is growing. Given the current uncertainties in the western economies, this demand may not be as strong over the next few years as at the start of the century. However, irrespective of growth it is likely that for some time to come energy demands will be met largely by fossil fuels such as oil, gas and coal (DTI 2007). Currently oil and gas provide more than 75% of the UK s total primary energy. In 2009, the UKCS natural gas production was enough to satisfy 68% of domestic consumption (OGUK 2010), produced mainly from fields in the SNS gas basin, with some production in the Central and Northern North Sea. Currently, the UK produces more gas than it consumes over a year leading to it being a net gas exporter since 1994. The UK s access to its own reserves has contributed greatly to its wealth. This security of supply has also enhanced the UK s self-sufficiency in the international arena, particularly at a time when increased competition for resources and global economic uncertainty is leading to high fluctuations in energy markets and fuel costs. Gas prices during 2010 were approximately half that of oil on an energy equivalent basis (OGUK 2011). The current UK Government energy policy is to encourage a low carbon economy whilst ensuring a secure and affordable energy supply. With these objectives in mind they have set out a number of policies in the Energy White Paper (DTI 2007) (see Section 2.1) to encourage a diverse low carbon electricity mix and maximise the recovery of economic gas reserves. Through a joint initiative with industry, the Government has been working on measures to encourage greater investment in the North Sea, which includes innovations to the licensing system, increased emphasis on brown field stewardship and the fallow initiative. The Energy Act takes a number of these measures forward, with focus on commercial measures to ensure security of supply during a Gas Supply Emergency (DECC 2011a). UK gas production peaked in 2000 and is now slowly declining by about 6% per annum. It is anticipated the gas production will continue to decline at around 6% annum in the near term, although much depends on the outlook for demand both in the UK and Internationally (OGUK 2011). As consumer demand ranges from 200 to 450 million m 3 per day, depending on the season, at some stage in the future the UK will switch to being a net importer. UK offshore gas production in 2009 was 62,798 million m 3 (DECC 2010). Assuming that offshore gas production declines in a similar manner to general UK gas production, i.e., a 6% decline, then production will reduce by approximately 3,770 million m 3 over the next year (approximately 10.3 million m 3 per day). When Cygnus comes on line in 2014, the maximum facilities capacity rate will be 250 MMscfd (7.1 million m 3 per day); although operation at production capacity is unlikely for an extended period. The estimated low, mid and high case production forecasts are provided in Figure 3-1 and Table 3-1. This demonstrates that the development will provide a significant volume of gas to offset the expected UK production decline. CF00-00-EB-108-00001 Rev C1 Page 13 of 300

Table 3-1 :, mid and high case production forecasts Year Case Mid Case High Case Gas rate (MMscfd) Cumulative Production (Bscf) Gas rate (MMscfd) Cumulative Production (Bscf) Gas rate (MMscfd) Cumulative Production (Bscf) 2014 38.4 14.0 37.4 13.7 38.9 14.2 2015 206.1 89.3 225.8 96.1 231.2 98.6 2016 224.4 171.4 232.5 181.2 232.5 183.7 2017 162.3 230.6 232.5 266.0 232.5 268.5 2018 120.4 274.6 223.8 347.7 232.5 353.4 2019 103.9 312.5 171.0 410.1 232.5 438.2 2020 76.8 340.6 128.6 457.2 231.1 522.8 2021 57.3 361.5 116.3 499.6 197.2 594.8 2022 42.6 377.1 113.0 540.9 159.5 653.1 2023 33.1 389.2 90.7 574.0 130.0 700.5 2024 23.4 397.8 68.8 599.2 116.1 743.0 2025 18.9 404.6 55.5 619.4 116.3 785.4 2026 16.9 410.8 45.2 635.9 106.0 824.1 2027 15.4 416.4 35.9 649.0 89.6 856.9 2028 14.1 421.6 25.8 658.4 76.3 884.8 2029 12.9 426.3 24.0 667.2 63.7 908.0 2030 10.8 430.3 20.8 674.8 55.2 928.2 2031 7.0 432.8 18.4 681.5 47.2 945.4 2032 2.9 433.9 17.1 687.8 40.5 960.2 2033 2.8 434.9 16.0 693.6 37.5 973.9 2034 2.7 435.8 15.0 699.1 34.5 986.5 2035 2.6 436.8 14.1 704.3 31.7 998.1 2036 2.5 437.7 10.9 708.2 29.3 1008.8 2037 2.4 438.6 10.1 711.9 24.8 1017.9 2038 2.3 439.4 8.6 715.1 23.4 1026.4 2039 2.3 440.3 4.8 716.8 20.4 1033.8 2040 2.2 441.1 3.7 718.2 15.4 1039.5 2041 2.1 441.9 3.6 719.5 12.5 1044.0 2042 2.1 442.6 3.5 720.8 12.0 1048.4 CF00-00-EB-108-00001 Rev C1 Page 14 of 300

Year Case Mid Case High Case Gas rate (MMscfd) Cumulative Production (Bscf) Gas rate (MMscfd) Cumulative Production (Bscf) Gas rate (MMscfd) Cumulative Production (Bscf) 2043 2.0 443.4 3.4 722.0 11.5 1052.6 2044 2.0 444.1 0.5 722.2 11.0 1056.6 2045 1.9 444.8 0.5 722.4 10.6 1060.5 2046 1.9 445.5 0.5 722.6 10.2 1064.2 2047 1.9 446.2 0.5 722.7 9.8 1067.8 2048 1.8 446.8 0.4 722.9 9.4 1071.2 Figure 3-1 : Cygnus low, mid, and high case forecasts In addition to the obvious benefits of increasing security of supply and national reserves, the use of gas as a primary energy source has led to improvements in UK air quality and a reduction in overall greenhouse gas emissions (OGUK 2004). The Climate Change Act (2008) has committed the UK to deliver an 80% reduction in greenhouse gas emissions between 1990 and 2050. Currently renewable energy sources in the UK contribute around 2% of the UK s total energy, however the UK has agreed the target of 15% of energy supplied by renewable sources by 2020 prescribed within the EU Renewable Energy Directive 2009 (2009/28/EC). Even if this target can be met, there is still the need for low carbon energy sources such as gas, and it is expected that the continued use of gas will help the UK to meet national and international targets for emissions. As established above the Cygnus development fits many of the UK energy policy objectives: It is a economically viable development that has been designed to maximise reserve recovery within an existing mature province CF00-00-EB-108-00001 Rev C1 Page 15 of 300

It is a low carbon fuel It is a national resource that will help to contribute towards energy security 3.2 ALTERNATIVES The consideration of alternatives to a proposed project is a requirement of many EIA processes and a standard requirement of the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) (Amendment) Regulations 2007. A comparison of alternatives helps to determine the best method of achieving the project by indicating the best available technology (BAT) or the best environmental practice (BEP) or at the very least the option which minimises environmental impacts. The type and range of alternatives considered might include: Supply or activity alternatives e.g., using the location to develop oil reserves or for alternative offshore technologies. Location alternatives, either for the entire project or for individual components e.g., the siting of a platform or the routing of a pipeline. Process or infrastructure alternatives e.g., use of waste-minimising or energy-efficient technology, establishing new infrastructure or using existing facilities. Scheduling alternatives e.g., to avoid sensitive periods of the year for particular environmental receptors. The World Bank recommends a tiered approach to the analysis of alternatives. It is designed to bring environmental considerations into all stages of development planning and ideally begins with strategic environmental assessment (SEA) to analyse broad alternatives within a region (Sadler and McCabe 2002). In the UK, a set of SEAs are in place which fulfils this purpose. This section discusses: Firstly, the alternatives to the proposed project (Section 3.2.1) i.e., why the development of an oil project is considered the best alternative for the area in relation to the UK energy strategy. Secondly, the alternatives that were considered within the project (section 3.2.2) e.g., location, process, infrastructure and scheduling alternatives. 3.2.1 Alternatives to the Proposed Project In light of declining fossil fuel reserves, part of the UK energy strategy is to encourage the development of alternative energy sources to ensure security of supply (DTI 2007). Offshore technologies being considered include wind farms and wave and tidal devices. Some of the technologies considered are not proven and currently it is only wind farms that are being actively developed on a commercial scale. The UK Government has set a target that 20% of the energy supply by 2020 will be supplied from renewable energy sources. The need to reduce carbon emissions whilst ensuring secure energy supplies means that the UK cannot rely on renewable energy alone. The UK will continue to need fossils fuels as part of a diverse energy mix for some time to come (DTI 2007) and as such the development of the Cygnus reserves is very much in line with the current UK energy policies. The Energy Act introduces measures to ensure the security of gas supply to the nation, highlighting the importance of gas to meet the current UK energy demands (DECC 2011a). In terms of alternative gas reserves, GDF SUEZ E&P UK is always looking for potential new sources of gas, but for commercial reasons they have to target proven reserves first. 3.2.2 Alternatives within the Proposed Project Over the last four years the Cygnus project has considered a number of different development options. Economic analysis, technical risk assessment and environmental studies have been conducted on export routes, development schemes and pipeline installation methods to ensure the options selected can be considered best practice. A summary discussion of alternatives is presented below. 3.2.2.1 Development options and export routes Since 2007 different development options have been considered for the field. The first option considered was a small development consisting of a single NPAI tied-back to existing subsea infrastructure. This option had the potential for further expansion during later phases. The option CF00-00-EB-108-00001 Rev C1 Page 16 of 300

was based on the results of the initial exploration well and one appraisal well. An ES for this development option was submitted to the DECC in March 2009 (GDF SUEZ E&P UK 2009). However, three further appraisal wells identified that the field was larger than initially thought and that additional assessment would be appropriate before selecting the export route and field layout in order to ensure it would be appropriate for the larger anticipated gas production. In June 2009 four potential export routes were reviewed based on the larger, phased development. These were: Connection to the WGT pipeline system to Den Helder Terminal, Netherlands: 89km this route would require export via the Markham Platform to the gas processing facility in Den Helder. This option included a significant pipeline length to allow tie-in to the Markham Platform. Connection to the NGT pipeline system to Uithuizen Terminal, Netherlands: 52.5km this route would incorporate a tie-in to the D15-FA-1 platform in the Dutch sector of the SNS with gas processed at Uithuizen. The tie-in to the D15-FA-1 platform was less distance than to that of the WGT route. In addition, as GDF SUEZ E&P UKs affiliate, GDF SUEZ E&P Nederland B.V., is operator of the D15-FA-1 platform it was considered that commercial risks associated with this option were relatively low. Caister-Murdoch System (CMS) to Theddlethorpe Terminal, UK: 27km this would require tie-in to the McAdam template with gas processing provided at the Theddlethorpe Terminal. ETS pipeline to Bacton Terminal, UK: 51km during the 2009 assessment, this option required tie-in at either the Trent or Tyne platforms to allow adequate compression prior to flow to the ETS 24" pipeline. The options were considered against specific criteria including review of capital expenditure, transportation, technical and commercial risks and flexibility for a wide range of full-field outcomes. Although environmental impacts were also considered, it was acknowledged that options were broadly similar in terms of environmental effects. The main differentiating criterion was the length of the export route. Although the NGT route was initially considered favourable, restrictions to ensure the gas was processed within the UK were prescribed by one of the partners and only the ETS and CMS options were considered during the final assessment. The CMS route had been considered favourite when the development was small, and was the initial export choice for the Phase 1 development in 2009. However, changes in the development plan and issues associated with engineering reduced the potential for this route. Changes to the field development plan following the 2009 assessment incorporated a Cygnus compression facility. This negated the need for additional compression offshore provided by either the Trent or Tyne platforms. The ETS pipeline option was therefore altered to a 51km pipeline from Cygnus directly to the ETS pipeline, near the Trent platform. The ETS pipeline tie-in would be engineered such that any shut-in of gas from the Trent platform or the Cygnus field would not affect the other. It was considered that the change to this option minimised risks and improved its position in comparison with the CMS route. The key consideration in the final choice of the export route was to ensure that the option chosen provided a roust export solution that could handle the forecasted gas production over a field life of 35 years. The ETS pipeline route was chosen as the favoured option as it presented the best technical and commercial alternative. 3.2.2.2 Schedule options GDF SUEZ E&P UK has reviewed the potential for an Early Production System (EPS) which would allow first gas in October 2013, a year earlier than the base case development option. The base case, presented in this ES, would generate first gas following installation of the Cygnus A wellhead and production utilities platforms. However an EPS would allow earlier first gas via production before installation of the process, utilities and accommodation platforms. Flow would then be switched from the EPS to the main process and utilities platform in November 2014. The potential environmental impacts of the EPS have been compared with the base case. The production of gas earlier will lead to higher emissions and there is the potential that more vessel movements will be undertaken as an additional lift will be required to install the EPS platform. However, the footprint of the EPS platform would be the same as the base case development and CF00-00-EB-108-00001 Rev C1 Page 17 of 300

therefore there will be no difference in the impact on the benthic community. There are no other significant differences in the environmental impacts of the two options. Following review, the base case has been selected for progression. It was determined that additional technical studies would be required for the EPS; if these identified that it was not viable, the delay caused by waiting for this information would have affected the base case schedule. It was considered that the base case presented the lower risk option. 3.2.2.3 Platform options In 2007 it was anticipated that a single NPAI would be installed at the Cygnus field. This would minimise the footprint of the installation, reduce maintenance and transport requirements and limit energy consumption compared to the current development option. However, it was proposed that further development of the field could incorporate up to six further platforms depending on the production levels encountered (Metoc plc 2009). The successful subsequent appraisal wells have led to changes in the way the field will be developed, requiring additional processing facilities to be available offshore before tie-in to the ETS pipeline. In order to achieve this, a manned installation is now considered the most appropriate solution; this will be a hub for the field, with an NPAI at Cygnus B used to support the drilling centre. A permanent manned attendance at Cygnus B is not considered necessary and this will minimise footprint, energy, and transportation requirements. Although this development plan will have a larger footprint than the originally proposed single NPAI, the development is for much larger volumes of gas than originally anticipated and the Cygnus A hub platform allows connection to the ETS pipeline with the associated benefits of this as discussed above. 3.2.2.4 Pipeline installation methods At an early stage of project planning it was identified that any export route would have to pass across an area of shallow sand bank within the Dogger Bank csac. The Dogger Bank is a unique, dynamic area of the North Sea (see Section 9 for details). Its designation as a csac means that any development undertaken within its boundaries must not affect the structure or integrity of the sandbank for which it is protected, especially as restoration of the sandbank and its flanks, if disturbed, is considered difficult or impossible (Johnston et al. 2004). Co-ordinated studies on the impacts of pipeline installation techniques on the marine environment especially relating to sandbanks are lacking. As such, to inform project design GDF SUEZ E&P UK commissioned a desk-study (Metoc plc 2008a) to compare four different installation techniques commonly used in the SNS: self-burial; jetting; non-displacement ploughing; and displacement ploughing (Table 3-1). Self-burial was rejected outright because of evidence that it has proved ineffective at achieving full burial in this area. Of the remaining three options, a combination of uncertainty about performance, technical limitations and commercial availability have led GDF SUEZ E&P UK to select the displacement trenching technique. It has not yet been determined whether the trench will be mechanically or naturally backfilled. Mechanically backfilling the trench will ensure 100% burial of the pipeline however the additional vessel movements and seabed disturbance will increase the potential impact on the environment. Modelling will be used where applicable and an assessment of BAT and BEP will be completed in order to ensure that the most appropriate option is selected. 3.2.3 Project Decisions A number of decisions have or will be made in relation to the project that could have a potential impact on the environment. GDF SUEZ E&P UK is committed to complying with the requirements of indicative BAT and has undertaken reviews of alternatives available to ensure that the most appropriate option is selected. The following detail a number of examples of the alternatives that have been considered. Pipeline laying methods - it is possible to lay the pipeline using an anchor lay barge or a DP vessel. The anchor lay barge causes disturbance of the benthic community and increased turbidity and the DP vessel can increase turbidity in shallow waters, cause scour of seabed sediments at shallower depths and may potentially impact pinnipeds (as discussed in Section 9.5.5). The assessment to determine the most appropriate method is not yet complete and therefore both options have been considered in the EIA. Produced water management there are a large number of methods of managing produced water including re-injection, export onshore, and using hydrocyclones and centrifuges to CF00-00-EB-108-00001 Rev C1 Page 18 of 300

manage oil in water concentrations. GDF SUEZ E&P UK will consider these to determine the most appropriate means of meeting the requirements of the DECC guidance on the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999 (as amended) (2009a). Hydrate inhibitor it has been determined that hydrate inhibitor is required to prevent hydrates forming in the intra-field pipeline between Cygnus A and B. Methanol and MEG were both considered and it has been determined that MEG is the more feasible option due to its high recovery rate minimising raw materials consumption and transport costs. Cooling systems a cooling medium and air cooling systems are being considered to provide cooling for separation of gas, condensate and water. The selection will be made based on cost, efficiency, space and weight, maintenance and environmental impacts. Heating systems waste heat recovery from the exhaust of the power generation units was considered in line with the requirements of indicative BAT. The study undertaken concluded that it is recommended that the development use direct electric heating instead of waste heat recovery due to the reduction in heating load and capex saving available. Additional fuel costs are offset by more reliable system and higher efficiency from power generation turbines operating at close to optimum loads. CF00-00-EB-108-00001 Rev C1 Page 19 of 300

Table 3-2 : Pros and cons of alternative pipeline installation techniques Option Burial mechanism Pros Cons Decision Self-burial Pipeline fitted with spoiler which facilitates erosion of seabed around pipeline causing pipeline to self-bury. Minimal seabed footprint approximately 1m wide corridor temporarily affected along pipeline route. Limited temporary disturbance to seabed and no increase in turbidity. Impact on benthic communities limited to 1m corridor along route length. Suitable for sediment compositions with high concentrations of sand and silt. Especially good for areas with high current speeds. Operators experience: At times in SNS technique has proved unreliable with full burial not guaranteed. Snagging hazard to commercial fishermen as long as pipeline is exposed (potentially 3 years). Reinstatement to original seabed conditions dependant on pipeline self-burying. Rejected due to uncertainty that full burial will be achieved. Jetting Water jets fluidise the seabed into which the pipeline sinks. Suitable for sandy sediments. Suitable for pipelines up to 16" diameter. No impact on commercial fishing as pipeline buried immediately. er levels of benthic smothering than ploughing. Impact footprint of 10m Increase in turbidity as surface sediment fluidised and suspended. Sediments expected to disperse and settle out in close proximity to trench. Limited mortality of benthic infauna in trench. Benthic communities take between 3 months and 2 years to recover from disturbance. Rejected. This technique provides the lowest environmental impact, but there is uncertainty over its performance in sediments along the pipeline route and commercial availability of required equipment. Nondisplacement ploughing Thin blade like share slices into seabed without creating a trench. Limited temporary disturbance to seabed and no increase in turbidity sediment is lifted up and replaced in-situ. Limited impact corridor of 3m along route. Mortality of benthic species limited to machine footprint (maximum of 3m along pipeline route). No impact on fishing as pipeline buried immediately. Technique limited to small diameter flexible pipelines, umbilicals and flowlines. Not optimal for sand. Rejected due to technical limitations relating to pipeline diameter and sediment conditions. Displacement ploughing Creates an open V shaped trench into which the pipeline is laid. Suitable for any sediment type. Suitable for any pipeline diameter. Impact footprint on seabed largest of techniques considered at 15m. Increase in turbidity as trench created. Sediments expected to disperse and settle out in close proximity to trench. Selected for technical and commercial reasons. In addition, the technique ensures the pipeline is buried to the required CF00-00-EB-108-00001 Rev C1 Page 20 of 300

Option Burial mechanism Pros Cons Decision Source: Adapted from Metoc plc (2008a) Mortality of benthic species within trench. Smothering of individuals in pipeline corridor from suspended sediment and spoil piles. Benthic communities take between 3 months and 2 years to recover from disturbance. depth minimising the requirement for later rock protection. CF00-00-EB-108-00001 Rev C1 Page 21 of 300

4.0 IMPACT ASSESSMENT METHODOLOGY 4.1 ENVIRONMENTAL IMPACT ASSESSMENT PROCESS In accordance with best practice and guidance 2 it is acknowledged that as a general approach, an EIA needs to take the following steps: Set management objectives and goals for the EIA by defining the applicable Institutional, Policy and Regulatory frameworks (Section 2) Describe what the project proponent intends to undertake and how the environmental considerations have formed an essential part in the development concept, definition and selection of the activities (Sections 3, 5 and 6) Describe environmental conditions and present an understanding of other resource uses for each significant environmental receptor (embedded in Sections 8, 9, and 10) Forecast how environmental conditions will change (Sections 4, 8, 9, and 10) Predict how the ecosystem components will respond (Sections 4, 8, 9, 10 and 11) Plan for mitigation (Sections 8, 9, 10 and 12) These steps are informed by the assessment team, the project engineering and management team and by stakeholder consultation throughout the EIA process as shown in Figure 4-1. Figure 4-1: Overview of EIA methodology 2 IUCN (1991), Royal Society for the Protection of Birds (1995), Truett et al. (1996), Glasson et al. (1999), DECC (2009) CF00-00-EB-108-00001 Rev C1 Page 22 of 300

4.1.1 Stakeholder Consultation Although not a statutory requirement, it is recognised best practice that EIA methodology should also include stakeholder consultation. Early consultation can often be a critical first step to the development of a comprehensive and balanced EIA, especially in areas of heightened sensitivity both environmentally and socio-economically. Views of the interested parties serve to focus the environmental studies and identify specific issues which require further consideration. Through previous project experience and consultation with the authorities, the key stakeholders identified for the Cygnus development are the DECC, the JNCC and CEFAS. Informal consultation with the aforementioned stakeholders on the proposed scope of the EIA, was commenced in February 2008 when the first proposals for development of the field were discussed. Consultation has continued following the changes to the project and they remain an ongoing process to ensure that the consultee comments and recommendations are appropriately captured. Consultation undertaken to date is detailed below: Regular meetings and telephone conversations with DECC s Environmental Management Team (Inger Soderstrom) throughout the project planning stages of the development and during preparation of the ES. DECC were made aware of the change to full field development during a meeting in February 2011 where suggestions of a number of areas that should be covered in the Environmental Statement were discussed. Meetings were held with DECC s Field Development team (Alison D Arcy) from March 2007 onwards to update the team of the proposed field development scenarios and sequencing of development Phases. Informal direction was received that sequencing was sufficient to fulfil license obligations and would be considered acceptable as a development scenario. GDF SUEZ E&P UK received general support for the plans but were asked that they keep the DECC informed periodically as plans progressed. The DECC highlighted that the ES should be consistent with the field development plan. Telephone conversation (November 2008) informing JNCC (Simone Pfeifer) of the proposed EIA methodology and ES layout. Further meetings were held (with Holly Niner) in February and June 2011 to update the JNCC of the change to full field development. The JNCC agreed that approach sounded reasonable and suitable and would be happy for the ES to progress using the described format. A number of areas were discussed for inclusion within the ES including the potential impact of ducted propellers on seals and the protected status of harbour porpoises in The Netherlands area of the Dogger Bank. Consultation was undertaken with CEFAS regarding the potential of herring spawning grounds, following the benthic survey at appraisal well 44/12A-C in 2008. CEFAS agreed that the site had a low herring spawning potential. Details of the consultation were provided in the PON15B application associated with the well (GDF SUEZ E&P Ltd 2008a). Consultation was held via email and through the SNS Environmental Network with Forewind about the potential for conflicts and cumulative impacts between the Cygnus development and the Dogger Bank wind farm development. Consultation is ongoing as both parties keep the other informed of progress. 4.1.2 Project Definition The first stage of the EIA process is to establish a detailed understanding of the project and its associated emissions. The project description provided in this EIA is based on the applicants field development plans submitted to the DECC. In order to gain consent to develop the field detailed plans covering reservoir evaluation, projected production figures, construction details, economics etc have to be submitted to the DECC. The EIA acts as a supporting document addressing the environmental impacts of the proposed plans. The project description in both documents should be consistent, although the EIA description will provide in-depth detail on activities, and installation and production techniques to identify and evaluate environmental impacts. The in-depth project description is developed in conjunction with the project engineers through meetings, provision of technical specifications and experience gathered on other projects. Through these activities aspects of the project that have the potential to interact with the CF00-00-EB-108-00001 Rev C1 Page 23 of 300

environment are identified and taken forward for the EIA. During these discussions, environmentally preferential alternatives are identified and discussed. 4.1.3 Establish Baseline Environment In order to assess the potential impacts resulting from the project it is necessary to identify the environmental and human conditions that currently exist at the site. The environmental and human attributes which are considered have been divided into the three categories below: The physical environment: air, climate change, water resources and seabed conditions (Section 8) The biological environment: plankton, benthic ecology, fish, shellfish and elasmobranchs, seabirds, marine mammals, protected sites and species (Section 9) The human environment: commercial fishing, shipping, archaeology, other seabed users such as other oil and gas developments, military practice and exercise areas, wind farms, recreational sea users, and marine aggregate extraction (Section 10) A good understanding of the baseline for these attributes has been achieved through two activities: Undertaking and review of primary (baseline) field studies Detailed review of all secondary resources (i.e., existing documentation and literature) The data sources used to describe each environmental or human receptor are listed at the beginning of each baseline sub-category in Sections 8, 9, and 10. A summary of the primary and secondary information sources used for the Cygnus Field development are as follows: 4.1.3.1 Primary Data The following site investigation surveys were commissioned to inform the Cygnus field development programme: Site Survey covering the areas of Cygnus A, Cygnus B and the Cygnus A to ETS pipeline tie-in (Senergy S&G 2011) Cygnus A Site Survey November 2008 (UTEC Survey Ltd 2009a,b) Cygnus to McAdam Pipeline Route Survey November 2008 (UTEC Survey Ltd 2009c,d) Cygnus Fault Appraisal Well Fault Block 5: 44/12a-E Site Survey June 2008 (Gardline Environmental 2008c) Cygnus Appraisal Well Fault Block 4: 44/12a-F Site Survey May/June 2008 (Gardline Environmental 2008d) Cygnus Appraisal Well 1: 44/12a-C Site Survey April 2008 (Gardline Environmental 2008a) Cygnus Appraisal Well 2: 44/12a-D Site Survey June 2008 (Gardline Environmental 2008b) Cygnus Exploration Well: 44/12a Site Survey September 2005 (Gardline Environmental 2005) Each survey consisted of geophysical and environmental surveys. Survey specifications are provided in Table 4-1. The extent of each survey and sampling positions are illustrated in Figure 4-2. CF00-00-EB-108-00001 Rev C1 Page 24 of 300

Table 4-1 : Survey specifications Site Geophysical 1 Geotechnical 2 Environmental 3 Reference Cygnus A Cygnus B Cygnus A to ETS Pipeline Tie-in 3km x 3km SSS 75m and 125m range 3km x 3km SSS 75m and 125m range SSS 50m (over wreck) 75m, 100m and 125m range plus magnetometer - 10 grab and 8 photography stations - 8 grab and 9 photography stations 58 CPT and 58 vibrocore 17 camera and day grab stations Cygnus A 1 km 2-10 grab & photography stations Cygnus to McAdam Pipeline Cygnus 44/12a-E Cygnus 44/12a-F Cygnus 44/12a-C Cygnus 44/12a-D Cygnus Exploration Well 27 km x 1.7 km 13 vibrocores and 17 CPT 1 km 2 Not used to inform EIA 1 km 2 Not used to inform EIA 1 km 2 Not used to inform EIA 1 km 2 Not used to inform EIA 1 km 2 Not used to inform EIA 13 grab stations & 12 photography stations 10 grab & photography stations 10 grab & photography stations 10 grab & photography stations 11 grab & photography stations 10 grab & photography stations Senergy S&G (2011) Senergy S&G (2011) Senergy S&G (2011) UTEC Survey Ltd 2009a,b UTEC Survey Ltd 2009c,d Gardline Environmental 2008c Gardline Environmental 2008d Gardline Environmental 2008a) Gardline Environmental 2008b Gardline Environmental 2005 1Single beam and multibeam echosounder, pinger, sub-tow boomer, HR seismic (excluding ETS pipeline tie in). 2 Core penetration test (CPT) and vibrocores. 3 Grab sampling, still and video photography. The aim of the surveys was to: Characterise the seabed and shallow geology in terms of topographical conditions, shallow geological and seabed features, sediment type and sediment particle size distribution Identify obstructions and debris on the seabed Characterise the benthic community Determine whether any features of conservation importance are present All data acquired were of good quality and sufficient resolution to identify physical and biological features of importance, if present. CF00-00-EB-108-00001 Rev C1 Page 25 of 300

54 40'N 1 40'E!(!(!(!(!(!(!(!(!(!(!( 1 50'E 2 0'E 2 10'E 2 20'E. 54 40'N Key Environmental Statement Figure 4-2: Survey extents Biological stations # Cygnus to ETS (2011)!( Cygnus A Platform Site (2009)!( Cygnus 44/12a-C (2008) 54 33'N!(!(!(!(!(!(!(!(!(!( #!(!(!(!(!(!(!(!(!(!( # # ##!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!( # #!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!(!( 54 33'N!( Cygnus 44/12a-D (2008)!( Cygnus 44/12a-E (2008)!( Cygnus 44/12a-F (2008)!( Cygnus Exploration Well (2005) SSS extent Cygnus 44/12a-C (2008) Cygnus 44/12a-D (2008) Cygnus 44/12a-E (2008) Cygnus 44/12a-F (2008) Cygnus Exploration Well (2005) Survey corridors Export pipeline survey corridor (2011) Infield pipeline survey corridor (2011)!( Land <20m water depth 54 26'N # 54 26'N NOTE: Not to be used for navigation Date Monday, June 6, 2011 14:38:27 Projection UTM Zone 31N Spheroid International 1924 Datum ED50 54 19'N 54 19'N Data Source File Reference Checked Gardline Environmental (2005) Gardline Environmental (2008a,b,c,d) UTEC Survey Ltd (2009a,b,c,d) Senergy S&G (2011), GEBCO, JNCC J:\P951\Mxd\O_Cygnus_ES\.mxd Figure 4-2 Survey Extents Produced By David Cook Reviewed By Anna Farley 1 40'E 1 50'E 2 0'E 2 10'E 2 20'E km 0 0.5 1 2 3 4 Metoc Ltd, 2011. All rights reserved.

4.1.3.2 Secondary data Other data on particular elements of the physical, biological and human environment were obtained from appropriate agencies where required. In addition, existing documentation and literature were used to compile the existing baseline. Specific details for the information resources relating to each aspect assessed are detailed in Sections 8 to 10. Some of the key secondary data sources used are given below. SEA 2 - Strategic environmental assessment undertaken by the DECC to inform licensing in the SNS (DTI 2001a) Offshore Energy SEA undertaken by the DECC to inform licensing of all energy developments in the UK (DECC 2009b) Offshore Energy SEA 2 undertaken by the DECC to update the OESEA undertaken in 2009 (DECC 2011b) Fisheries sensitivity maps for British waters (Coull et al. 1998) Block specific seabird vulnerability tables for the UK (JNCC 1999) Cetacean population estimates and distribution obtained from the Sea Mammal Research Unit (SMRU) in the form of the Small Cetaceans in the European Atlantic and North Sea (SCANS-II) final report (SCANS-II 2008) and from the Joint Nature Conservation Committee in the form of the Atlas of cetacean distribution on the north-west European Continental Shelf (Reid et al. 2003) Dogger Bank SAC selection assessment document and draft conservation objectives and advice on operations (JNCC 2010a; 2011a) UK coastal atlas of recreational boating (RYA 2008) Marine Management Organisation (MMO) commercial fishery catch, landing and effort statistics for the period 2002 to 2010 (MMO 2011) GDF SUEZ E&P UK commissioned shipping collision risk assessments for the field development (Antatec 2011; 2008a,b,c) Information on UK existing oil and gas developments (UK Deal 2011) License boundary information from the Crown Estate on wind farms and marine aggregate extraction areas (The Crown Estate 2011) The following limitations or assumptions were made when establishing the project environmental baseline: Third party and publicly available information is correct at the time of publication Baseline conditions are accurate at the time of physical surveys but due to the dynamic nature of the environment, conditions may change during the construction, operation and decommissioning phases of the development The development, including surrounding area, will not be subject to unforeseen events of a severe nature 4.1.4 Identification of Project Aspects Once baseline information was collated, the assessment of potential changes to the baseline, resulting from the Cygnus development, required the identification of project aspects. A project aspect is defined as an element of an organisations activities, products or services that can interact with the environment (BSI 2004). To identify the project aspects, proposed activities as described in Section 5, are considered for the construction, operational and decommissioning phases, in terms of their direct or indirect potential to: Breach relevant legal standards, corporate environmental policy and management systems Interact with the existing natural environment including its physical and biological elements Interact with the existing human environment CF00-00-EB-108-00001 Rev C1 Page 27 of 300

4.1.5 Determination of Potential Impacts 4.1.5.1 Scoping An Interaction Matrix was developed to illustrate the identified interactions of project aspects and environmental and human resources in a consistent and robust manner. An example of the matrix is included in Table 4-2. Potential impacts were identified through a systematic process whereby each individual project activity was considered with respect to its potential to interact with a physical, biological or human receptor. The project aspects were identified as outlined above and were listed down the vertical column (or y axis) of the scoping matrix. The horizontal (or x ) axis was comprised of environmental and human resources and receptors that are susceptible to impacts, grouped into physical, biological and human components. Based on their experience, an understanding of the project description, and the nature and extent of project aspects, the assessment team identified whether a project aspect had the potential to interact (positively or negatively) with the environmental receptors. If it was deemed possible that an interaction may occur this was recorded as a tick ( ) in the matrix cell at the intersection between the aspect and the receptor. The completed Matrix is provided as Appendix 2 for reference. Table 4-2 : Extract from the Cygnus issues scoping matrix Environmental Receptor Physical Biological Human Project Aspect Physical presence and movement of transportation Air quality Climate change Water resources Seabed sediments Plankton Benthic ecology Fish and shellfish Seabirds Marine mammals Protected sites and species Commercial fishing Shipping and navigation Archaeology Other marine users* Drilling of wells 4.1.5.2 Prediction and Assessment of Potential Impacts The prediction of impacts (risk assessment) was undertaken to determine what could happen to the receptor (i.e. environment and human) as a consequence of the project and its associated activities. The diverse range of potential impacts considered in the EIA process resulted in a range of prediction methods being used including quantitative, semi-quantitative and qualitative methods. The impact prediction and assessment process took into account any mitigation or control measures that are part of the project design/project plan. Additional mitigation measures aimed at further reducing identified impacts are then proposed where necessary or as appropriate. Table 4-3 provides an example of an activity associated with the Cygnus development, its aspects and potential impacts. If an aspect has a number of different impacts, they may be assessed separately. Table 4-3 : Example development activity, aspect and impact identification Project Activity Aspect Impact Power generation Exhaust gas emissions Localised deterioration in air quality CF00-00-EB-108-00001 Rev C1 Page 28 of 300

Once the impact has been identified, its significance is assessed using the following criteria: Likelihood - This is an important significance criterion as it relates to the probability of a specified outcome or the chance of something happening. Those impacts which will definitely occur during the project lifetime would have higher significance than those which are unlikely to occur within the UKCS or the whole oil and gas sector worldwide. Spatial Extent - Localised or site specific adverse environmental effects may not be significant. Alternatively, widespread effects may be significant. When considering this criterion, it is important to take into account the extent to which adverse environmental effects caused by the project may occur in areas far removed from the development area or may contribute to cumulative environmental effects. Magnitude - The severity of the adverse environmental effects. Definitions of magnitude qualifiers are presented in Table 4-4. or negligible effects may not be significant. On the other hand, if the effects are high or catastrophic, the adverse environmental effects will be significant. When using this criterion, it is important to consider the extent to which the project could trigger or contribute to any cumulative environmental effects. Duration and Frequency - Long-term and/or frequent adverse environmental effects may be significant. Future adverse environmental effects should also be taken into account. When considering future adverse environmental effects, the question of their likelihood becomes very important. Table 4-4 outlines the assessment factors used for each criteria to define the potential impacts associated with the Cygnus development. Table 4-4 : Assessment process for identification of potential impacts Impact Factor Impact Classification Definite Will occur during project Definition Likelihood Possible Likely to occur several times per year and/or on a 1 to 5 year timeframe Unlikely Wider Environment Infrequently occurs in the UK exploration and production industry (e.g., <1 per year in whole UKCS or in Regional, whole sector national worldwide) global Spatial Extent Magnitude Duration Local Site Specific High Medium Long-term Medium-term Short-term Within development footprint and circa 10km radius of surrounding area Within development footprint Large change compared to variations in baseline Change which may be noticeable Change to baseline may only just be noticeable Effect for >10 years 2+ years Up to 2 years Is it noted that the determination of potential impacts consistently across different natural and socio-economic environments can be difficult. Scientific evidence as well as predictions based on observation of similar activities has been used in the impact assessment process. CF00-00-EB-108-00001 Rev C1 Page 29 of 300

4.1.5.3 Nature of Impacts In considering impacts related to this project, both negative and positive impacts have been identified. Furthermore, direct, secondary, indirect and cumulative impacts are also considered. These are further described below: Negative Impact - an impact that is considered to represent an adverse change from the baseline condition or introduces a new undesirable factor Positive Impact - an impact that is considered to represent an improvement on the baseline condition or introduces a new desirable factor Direct Impact - impacts that result from a direct interaction between a project activity and the receiving environment (e.g., between occupation of an area of seabed and the habitats which are lost) Secondary Impact - Impacts that follow on from the primary interactions between the project and its environment as a result of subsequent interactions within the environment (e.g., loss of part of a habitat affects the viability of a species population over a wider area) Indirect Impact - Impacts that result from other activities that are encouraged to happen as a consequence of the project (e.g., project implementation promotes service industries in the region) Cumulative Impact - Impacts that act together with other impacts to affect the same environmental resource or receptor 4.1.6 Mitigation of Potential Impacts Mitigation measures are the actions or systems that are used, or have been proposed, to manage or reduce the potential negative impacts identified. They may also be used to enhance the positive benefits, especially in relation to human issues. Application of mitigation measures to reduce potential negative impacts and enhance the benefits of a proposed activity is achieved by the application of the following mitigation hierarchy: Avoid at Source/Reduce at Source: Designing the project so that a feature causing a potential impact is designed out or altered. Abate on Site: This involves adding something to the basic design to abate the potential impact pollution controls fall within this category. Abate at Receptor: If a potential impact cannot be abated on-site then measures can be implemented off-site. Repair or Remedy: Some potential impacts involve unavoidable damage to a resource. Repair involves restoration and reinstatement measures. Compensate/ offset: replace in kind or with a different resource of equal value. Mitigation is an integral part of the Cygnus Field development. Where standard recognised best practice mitigation measures are not sufficient to reduce the impact, measures specific to the project that are feasible and cost effective have been proposed. The mitigation measures considered pertinent for each environmental and human issue considered are outlined in the individual technical sections to follow and summarised in Section 13, Table 13-1. 4.1.7 Residual Impact Assessment Any impacts remaining after mitigation measures have been applied are considered residual impacts. The significance level of the residual impacts identified for the proposed development is determined by considering the sensitivity, recoverability and importance of the receptor. Table 4-5 outlines the factors which are considered and the classification criteria which are applied to each residual impact. CF00-00-EB-108-00001 Rev C1 Page 30 of 300

Table 4-5 : Residual impact assessment criteria Residual Impact Factor Impact Classification Definition Sensitivity Recoverability High A very large change to baseline, e.g., : Moderate High Severe or persistent damage over a large area or to the entire population / habitat. Ongoing breaches well above statutory or prescribed limits Long term loss or significant hazard to users, resulting in major financial consequences for the company. Medium to large change compared to baseline, e.g.,: Large scale but not permanent damage to entire population / habitat. Localised or medium-term damage to portion of the population / habitat Repeated breaches of statutory or prescribed limits Financial loss or moderate nuisance to users A change is noticeable when compared to baseline but no lasting effect, e.g., : Localised or short-term damage to portion of the population / habitat. Single breach of statutory or prescribed limit. May affect behaviour but is not a nuisance to users. Trivial or no damage to population / habitat. Full recovery within few weeks or at most 6 months Moderate Full recovery, but will be complete within 6 months to 2 years Full recovery, but will be complete within 5 years Importance High Moderate It represents either a very rare/unique/valuable/ecologically important feature It represents an uncommon or moderately valuable feature but is not rare or unique Is of low importance and is neither rare, unique or of high economic value or does not play an important role in the ecosystem Using a three tier ranking system and following the flow diagram illustrated in Figure 4-3 an overall impact significance value of, Medium or High is then concluded. CF00-00-EB-108-00001 Rev C1 Page 31 of 300

Figure 4-3 : Residual impact significance assessment process Sensitivity Moderate High Recoverability High Moderate Importance Moderate High Moderate High Significance Medium High Based on the outcome of the significance assessment the following points need to be considered: High Significance Check that the residual impact has been subject to feasible and cost effective mitigation where possible Where no further reduction in impact levels can be made, it remains a High-level impact and which may therefore be subject to offsets Medium Significance Check that the residual impact has been subject to feasible and cost effective mitigation and that no further measures are practicable Significance Not mitigated further An assessment of the significance of the residual impacts from the Cygnus development was undertaken and the results are presented in the technical assessment sections (Section 8 to 10) to follow and Appendix 2. 4.2 CUMULATIVE AND INDIRECT IMPACTS In accordance with the EIA regulations, the EIA has given consideration to cumulative and indirect impacts and interactions. The definitions of these three types of impact overlap, generally without any agreed and accepted definitions. For the purposes of this assessment, the definitions proposed by the European Commission (1999) have been used. The definitions are as follows: Indirect Impacts Impacts on the environment, which are not a direct result of the project, often produced away from or as a result of a complex pathway. These are sometimes referred to a secondary impacts. An example of an indirect impact is the impact on commercial fish landings as a consequence of the poor stock recruitment because seabed disturbance has caused the loss of spawning grounds. Cumulative Impacts Impacts that result from incremental changes caused by other past, present or reasonably foreseeable actions together with the project. Cumulative impacts can either be the interactions of the same type of activity within: A single current project e.g., habitat loss caused by pipeline trenching added to the habitat loss cause by the installation of subsea structures leading to an overall larger area of habitat loss than one activity on its own. CF00-00-EB-108-00001 Rev C1 Page 32 of 300

Two projects in the same area whether this be historic, future, or a different industry e.g., habitat loss caused by the Alma field development combined with the habitat loss caused by the decommissioning of the previous fields combined with the habitat loss of trawling leading to an overall larger area of habitat loss. Impact Interactions The reactions between impacts whether between the impacts of just one project or between the impacts of other projects in the area. For example, the discharge of oil in produced water and the discharge of chemicals could individually not have an impact on water quality but combined could mean quality deteriorates past threshold levels. Impacts considered in this ES relate to impacts due to the project and: Other activities within the project Other oil and gas projects (past, present and future) Other seabed users e.g., commercial fishing, wind farms, marine aggregate extraction Climate change e.g., changes in sea level The assessment of cumulative impacts has been dependant on the public availability of consented developments. It is generally acknowledged that there are difficulties in assessing cumulative impacts via a single-project EIA and as such the DECC undertook a series of SEAs to strategically address cumulative impacts from oil and gas projects on a regional scale. In accordance with the EIA regulations the SEAs evaluate "any direct or indirect effects (including secondary, short, medium and long-term, permanent and temporary, positive and negative effects) resulting from the existence of the activity, the use of natural resources and the emission of pollutants, the creation of nuisances and the elimination of waste". Section 11 presents, quantitative assessments of the cumulative and indirect impacts and interactions (where possible), qualitative descriptions of impacts including the spatial and temporal scope of the assessments and a discussion of which impacts have not been addressed and why. CF00-00-EB-108-00001 Rev C1 Page 33 of 300

5.0 PROJECT DESCRIPTION The project description covers activities to be undertaken during construction, commissioning, production, and the decommissioning of the development after the end of production life. Also provided in this section is an outline schedule, setting out the likely timetable over which these activities will be performed. The section provides the basis upon which the prediction and evaluation of the environmental and human impacts has been conducted. The key elements of the included in this study are: Installation of Cygnus Platforms Installation of subsea export and intra-field pipelines Drilling of ten wells Operations Decommissioning An overview of the field development is shown in Figure 5-1 below. 5.1 SCHEDULE The construction schedule at Cygnus has been divided up into four key stages which are summarised in Table 5-1 below. Construction is scheduled to commence April 2013 with first gas anticipated for November 2014. Development drilling will commence from May 2013 and continue through to September 2016. CF00-00-EB-108-00001 Rev C1 Page 34 of 300

Figure 5-1: Layout CF00-00-EB-108-00001 Rev C1 Page 35 of 300

Stage 1 Table 5-1 : Cygnus construction schedule Activity 2012 2013 2014 2015 2016 Install and pile WYE and SSIV manifold Lay & trench 24" Export Pipeline Tie-in to ETS pipeline and test Cygnus A Hub Wellhead platform Drilling at Cygnus A (4 wells) Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Stage 2 Cygnus A QU Platform Cygnus A PU Platform Stage 3 Install Cygnus B Satellite Platform Lay & trench 12" infield pipeline & umbilical Drilling at Cygnus B (5 wells) Cygnus A 1st Gas Cygnus B 1st Gas Stage 4 Compression module on Cygnus A PU platform Compression available Drilling at Cygnus A (1 well) CF00-00-EB-108-00001 Rev C1 Page 36 of 300

5.2 CONSTRUCTION The activities involved during the construction phase will include installation of the Cygnus A Hub platforms, the Cygnus B satellite platform, development drilling of ten wells and installation of necessary support infrastructure e.g., export and intra-field pipelines, umbilicals and subsea structures. 5.2.1 Platforms The Cygnus field development will have two drilling centres with facilities for a permanently manned main production, dehydration and compression platform (Cygnus A hub) with an export pipeline. The outlying Cygnus compartments that cannot be reached from wells from the hub facility will be developed by a not permanently attended installation (NPAI) (Cygnus B) tied back to the hub facility via an intra-field pipeline. Provision on Cygnus A has been made to allow future tiebacks from nearby prospects and third parties. 5.2.1.1 Cygnus A Hub design and facilities The Cygnus A Hub will be a permanently manned installation and will consist of three bridge linked platforms with provision for a compression module to be installed at a later date: Production wellhead platform (W) Process and utilities platform (PU) Utilities and living quarters platform (UQ) Compression module (K) Reservoir productivity indicates that gas will initially be able to flow under natural reservoir pressure (i.e., no artificial lift is required). Therefore, installation of the compression module at Cygnus A will be deferred for 18-48 months dependant on reservoir performance. Production Wellhead Platform (W) The W Platform will consist of a four-legged, piled jacket supporting an integrated deck suitable for cantilevered jack-up drilling and will be bridge-linked to the PU Platform. The W platform will include the following facilities: Slots for 10 wells Platform gas capacity 250 MMscfd Platform flare capacity 250 MMscfd Platform condensate capacity 750 b/d Platform water capacity 1000 b/d Fracture stimulation support - Up to three wells may potentially require fracture stimulation at Cygnus A. The platform design will have the ability to undertake well fraccing without the use of a rig either via permanent or temporary clean-up facilities. Deck space will therefore be provided to accommodate coiled tubing intervention and well clean-up operations. A pedestal crane with a 20 tonne lifting capacity, sized for the installation of the coiled tubing intervention and well clean-up equipment. Process and Utility Platform (PU) The PU platform will consist of a six-legged, piled jacket supporting a 3,300 tonne modular topside and will support full processing to export specification. The platform will include the following facilities and process streams: Two 150 MMscfd processing trains for Cygnus A and Cygnus B production respectively and 75 MMscfd test separator for platform wells. Metering will be provided for gas and liquid metering to a fiscal standard prior to export. TEG dehydration system to remove water from the gas preventing hydrate formation in the export and ETS pipelines. CF00-00-EB-108-00001 Rev C1 Page 37 of 300

Controls An integrated process control system will be used to control both the Cygnus A and Cygnus B platforms (via the umbilical) and there will be a communications link to the Bacton terminal which will allow the terminal to remotely shut down production in the event of a major incident. Monoethylene glycol (MEG) and chemical injection system MEG and corrosion inhibitors are required to prevent damage in the intra-field pipeline between Cygnus B and A. Power generation - Two 3.1 MW dual fuel generators. Other systems heating and cooling; diesel storage, treatment and distribution; fuel gas system. Drains non-hazardous and hazardous drainage systems. Flare boom. Produced Water (PW) degassing and disposal overboard. General facilities Cranes, fire fighting pumps and equipment. Compression Module - The compression module will be installed on the PU platform. It will include two 60% capacity, 2-stage booster compression trains. These will compress the gas from 20bar up to 110bar for transfer into the export and ETS pipeline. The compressors will be driven by gas turbines with a maximum rated output of 7MW each. Utility and Living Quarters Platform (UQ) The UQ platform will consist of a four-legged, piled jacket supporting a 2,500 tonne single-lift integrated deck. This platform will provide accommodation for 65 persons. It will have a helideck sized for Sikorski S61 or EC225 helicopter and will be bridge-linked to the PU Platform. Additionally, it will have one ram luffer crane, an 800kw diesel emergency generator, a seawater lift and filtration system, a 230kw instrument and plant air system, two 530m 3 diesel driven firewater pumps, an inert gas generator and two 90 person TEMPSC survival craft. Cygnus A Future Modifications and Expansion The design of the Cygnus A hub will include two pairs of spare risers/j-tubes to allow for future tiebacks from nearby prospects and third parties. The shallow water of the Cygnus Field area means that further bridge linked platforms could potentially be installed to allow additional risers and processing facilities to be added as required. 5.2.1.2 Cygnus B NPAI design and facilities Cygnus B NPAI will be tied back to the Cygnus A hub. It will consist of a four-legged, piled jacket supporting integrated deck topsides weighing 1,900 tonnes, suitable for cantilevered jack-up drilling. The satellite platform has been designed to: Support up to ten wells with full well stream transfer to the central processing facility on Cygnus A, however only five wells will initially be drilled. Handle 150 MMscfd peak production rate Platform condensate capacity 450 b/d Platform water capacity 1000 b/d It will include the following facilities: Emergency shelter and support accommodation for 20 persons, one 30 person TEMPSC survival craft and a helideck suitable for Sikorski S61 or EC225 helicopters. Fracture Stimulation Support - There are no plans for well fraccing at the Cygnus B centre, however it will accommodate coiled tubing for potential well fracture intervention without a drilling rig. MEG injection MEG is received from the Cygnus A PU platform and will be injected into the intra-field pipeline to provide hydrate inhibition. Water knockout before transfer of the remaining well stream to the Cygnus A PU platform. CF00-00-EB-108-00001 Rev C1 Page 38 of 300

Hydraulic power unit. Topsides production system. Metering individual wet gas meters on each well and a test separator are being considered. Communication utilities, power, chemical injection and telecommunications via subsea umbilical to/from the Cygnus A. General facilities Pedestal crane with a 25 tonne lifting capacity. 5.2.1.3 Platform Installation All the platforms at Cygnus will be fixed to the seabed using driven piles. The number and size of the piles depends on the platform (see Table 5-2). All piles will be driven to 56m penetration. Table 5-2 : Pile sizes and numbers Platform Number Size Cygnus A Wellhead (W) 4 1.5m (60") Cygnus A Process & Utility (PU) 6 1.5m (60") Cygnus A Utilities and Living Quarters (UQ) 4 1.2m (48") Cygnus B NPAI 4 1.5m (60") Total 18 - Installation of the platforms will take place from a heavy lift vessel. Each platform will be transported to the field from its construction yard and will be installed in approximately 20 days. Pile driving is anticipated to take six hours per pile. Figure 5-2 : Delta flipper anchor Anchors will be used to maintain the heavy lift vessel in position at the platform site. It will take approximately six hours to deploy the anchors and six hours to retrieve them. Twelve delta flipper 22½ tonne anchors (Figure 5-2) will be used. Anchors will be limited to an established anchor pattern within 1,000m of the platform site, as illustrated in Figure 5-3. When the anchor is deployed it buries itself into the sediment, displacing sediment into a mound in front of the anchor. Self burial stops when the sediment meets the envisioned anchor wire tension (approximately 100 tonnes). The amount of sediment displaced is largely dependent on the sediment characteristics in the area. Anchor mounds are common where seabed sediments are composed of fine sands or clay. In addition, when the anchors are lifted clear, the anchor fluke will also lever sediment onto the seabed adding to the mound. The horizontal extent of the mound has been estimated as 10-15m. Assuming each anchor disturbs a circular area 15m in diameter, the spread will have a footprint on the seabed of 2,124m 2 at each site. The anchors will be attached to the heavy lift vessel with a chain and cable combination. During the running of the anchor the chain and cable will probably touch the seabed, potentially causing a scour in the surface sediments in a straight line from the anchor deployment location to the heavy lift vessel. However, once the anchor wire is tensioned, the wire and cable will not drag on the seabed. CF00-00-EB-108-00001 Rev C1 Page 39 of 300

2 9'E 2 12'E 2 15'E 2 18'E 2 21'E Cygnus Environmental Statement Figure 5.3: Extent of anchor spread 54 36'N 54 36'N Legend Proposed project development Cygnus export pipeline Intrafield pipeline <20m water depth Anchor positions Standby Operational 54 34'N 54 34'N Survey extent (2011) Export pipeline survey corridor (2011) Infield pipeline survey corridor (2011) Biological station 2 9'E 2 12'E 2 15'E 2 18'E 2 21'E Date Monday, June 13, 2011 18:33:55 Heavy Lift Vessel (standby position) Heavy Lift Vessel (standby position) Projection Spheroid UTM_Zone_31N International_1924 Cygnus B NPAI Cygnus A Hub Datum Data Source File Reference ED 50 GEBCO, JNCC, UKDEAL, J:\P951\Mxd\O_Cygnus_ES\.mxd Fig 5-3 Extent of anchor spread_v1 Checked Produced By Reviewed By David Cook Anna Farley 0 0.5 1 2 3 km Metoc ltd, 2011. All rights reserved.

5.2.2 Wells The Cygnus field will be developed with five horizontal gas wells drilled from each of the two drill centres (Table 5-3), in order to achieve the optimum field drainage whilst minimising the overall drilled footage. This, in turn, will minimise the environmental footprint. Table 5-3 : Cygnus development well summary Drilling centre Well name Fault Block Target reservoir Expected Completion Type Horizontal Cygnus A BK1-1 Block 1 Leman Potential Frac Cygnus A BK1-2 Block 1 Leman Potential Frac Cygnus A BK2a-1 Block 2a Leman Potential Frac Cygnus A BK2b-C1 Block 2b Carboniferous Standalone Sandscreens Cygnus A BK2b-C2 Block 2b Carboniferous Standalone Sandscreens Cygnus B BK2a-C1 Block 2a Carboniferous Standalone Sandscreens Cygnus B BK3-1 Block 3 Leman Standalone Sandscreens Cygnus B BK3-2 Block 3 Leman Standalone Sandscreens Cygnus B BK4-1 Block 4 Leman Standalone Sandscreens Cygnus B BK4-2 Block 4 Leman Standalone Sandscreens The wells will be drilled using a single jack-up drilling rig which will be moved between the two drill centres, with the drilling derrick cantilevered over the respective platform. The wells will terminate with a wellhead and a dry Xmas tree. The schedule design is for the first four wells to be drilled at Cygnus A followed by relocation of the rig to Cygnus B, where all five wells will be drilled. The rig will then relocate back to Cygnus A to drill the tenth and final well. Opportunities to reduce the number of rig moves are currently being explored along with any potential efficiency savings by batching any operations. There is a contingent requirement that up to three wells on the Cygnus A platform will need to be hydraulically fractured (Block 1 and Block 2a Leman wells). The Cygnus A facilities will allow for the fracturing of these wells without the use of a rig and will accommodate permanent de-sanding facilities. Currently, there is no plan for fracturing at the Cygnus B NPAI; however, this may be reconsidered in the future. If fracturing is required, temporary equipment will be used. 5.2.2.1 Drilling rig The wells will be drilled using a jack-up drilling rig similar to the ENSCO 100. Jack-up rigs are selfcontained drilling units on a floating barge fitted with long support legs that can be raised or lowered independently. Typically a jack-up drilling rig hull is 90m long by 89m wide with a 9m draft. Jack-ups are capable of operating in depths of up to 100m, drilling to depths of approximately 9,150m and accommodating up to 106 personnel. To support the drilling operation, the following systems and services are located on the rig: CF00-00-EB-108-00001 Rev C1 Page 41 of 300

Bulk Storage provided for fuel oil, bulk mud and cement, liquid mud, drill water and potable water. Pipe and Materials Storage covered storage is provided for sacked material, drilling equipment, spares etc. and deck storage for drill pipe casing. Helideck rated for a Sikorsky S-61r helicopter or equivalent. Craneage up to four cranes provided for transferring equipment and supplies from vessels. Environmental Protection hazardous and non-hazardous drainage systems (which respectively allow transfer to tote tanks for shipment to shore and disposal by licensed waste contractors or collect rainwater and / or any minor spills to a drains tank for treatment prior to discharge to sea) and sewage treatment unit. Sewage discharge from the rig undergoes treatment prior to release. This can vary from fine screen maceration to full enzyme degradation. Alternatively it will be discharged to a supply vessel for onshore treatment and discharge. Upon arrival at the proposed drilling location the legs are jacked down to the seafloor and preloaded to firmly drive the spud cans (feet) into the seabed (Figure 5-4). Once the legs are securely in the seabed i.e., they will not penetrate any deeper, the legs are jacked up further which raises the drilling platform above the water so that it is above the effects of waves. At Cygnus A and B the drilling rig will come along side the platform, the drilling derrick will be skidded (positioned) over the platform, and the wells drilled through the platforms (Figure 5-4). Figure 5-4 : Positioning jack-up rig Moving Jack-up jack-up rig rig Stationary platform Above: Photo of jack-up rig alongside stationary platform Left: Artists impression showing position of jack-up rig and platform above and below sea surface. Source: http://www.offshore-technology.com Stationary platform 5.2.2.2 Rig Stabilisation Of the five wells drilled between 2006 and 2010 within the Cygnus project area by GDF SUEZ E&P UK, three have required rock material to be deposited around the spud cans for the purposes of rig stabilisation (i.e. to ensure that the rig did not tilt or fall). These wells were all drilled during the winter months, when storm conditions and strong currents caused scour around the rig legs. Drilling at the Cygnus field development will be continuous through 2013 to 2016 and therefore it is probable that rig stabilisation will be required at some point. CF00-00-EB-108-00001 Rev C1 Page 42 of 300

If rig stabilisation is required, a maximum of 3,000 tonnes of rock will be placed on the seabed around the spud cans at any one time. However, due to the length of the drilling campaign it may be necessary to repeat this treatment more than once at each site. If this is necessary, material will be placed on top of the existing rock and therefore the seabed footprint is unlikely to increase substantially. GDF SUEZ E&P UK will use a side stone dumping vessel to position freshly crushed, granite/gneiss rock (size ranging from 2cm to 20cm in diameter) on the seabed. Post drilling surveys (Gardline Geosciences Ltd 2009a,b) undertaken at the Cygnus 44/12a-3 and 44/12a-4 wells provided quantitative values of the rig stabilisation footprints. These have been used to provide the estimate of the impact footprint from the Cygnus field development presented in Section 6.1.3. Evidence from the other wells, and in particular a post drilling seabed survey carried out in 2008 at the Cygnus exploration well location, indicated that rock material is covered by a thin layer of sand within three months (Rudall Blanchard Associates Ltd 2008). 5.2.2.3 Drilling The two main types of drilling fluids (muds) typically used in offshore drilling, i.e. water based mud (WBM) and low toxicity oil based mud (OBM), will both be used during drilling operations at Cygnus. Drilling muds have five primary purposes: To remove the cuttings (produced by the drill bit) from the formation and carry them to surface To lubricate and cool the drill bit during operation To maintain hydrostatic pressure so that gas and fluids from the formation do not enter the well bore causing a kick or blow-out To build a filter cake on the hole wall to prevent fluid loss to the formation To support and prevent caving of the wall of the hole The drilling rig circulates the mud by pumping it through the drill string to the drill bit. From here it travels back up the annular space between the drill string and the sides of the hole being drilled. The circulating system is essentially a closed system with the mud recycled throughout the drilling of the well. Various products may be added to make up for losses (to formation), to adjust the mud s properties, or to overcome difficult conditions (e.g., stuck drill pipe or loss of well pressure). In the case of WBM discharge of mud and cuttings is normally to sea. In the case of Cygnus discharge will be at the sea surface from the rig. OSPAR Decision 2000/3 prevents the discharge of OBM to the marine environment, thus all returned OBM fluids and associated drill cuttings will be skipped and shipped to shore for thermal processing 1. The primary design solution for the Cygnus Field is for slim bore wells comprising: A 30" conductor set approximately 100m below the sea bed A 17 ½" section drilled with WBM to about 1000m within the Upper Cretaceous. A 12 ¼" section, drilled with OBM into the top Zechstein will be to approximately 2800m An 8 ½" section, will be to approximately 4000m and will be drilled across the Zechstein and into the Basal Carbonate sequence. It is probably to be drilled with OBM, although the use of WBM for this section is being evaluated. A 6" section into the Silverpit sequence will probably be drilled with OBM; however, use of WBM is being evaluated. The target depth for this section is 5400m. However, due to the size of the field and diversity of reservoir type and quality, it is recognised that several different completion concepts will be required. Consequently, GDF SUEZ E&P UK is also considering a contingent large-bore well design, dependent upon the type of completion used, consisting of: A 30" conductor set approximately 100m below the sea bed A 26" hole section will be drilled through the conductor and down to the 20" casing point within the Upper Cretaceous using WBM. Drill cuttings and WBM will be returned to the rig and discharged to sea at surface. CF00-00-EB-108-00001 Rev C1 Page 43 of 300

The 17 ½" hole section will then be drilled through the Upper Cretaceous and Haisborough Gps down to about 2800m within the top Zechstein using OBM A 12 ¼" section across the Zechstein, will be drilled to approximately 4,000m. It will most likely be drilled with OBM, although the use of WBM for this section is being evaluated An 8 ½" section, drilled too approximately 4300m through the Basal Carbonate sequence probably to be drilled with OBM, although the use of WBM for this section is being evaluated A 6" section will be drilled to the target depth of 5,400m and will probably be drilled with OBM; however, use of WBM is being evaluated Both slim-bore and large-bore designs have been adopted extensively across the SNS. Based on experience it is expected that the large-bore well design will be required for up to two wells. It is assumed that the total depth of the wells will be less than 18,000ft (5,400m). Drilling to this depth will facilitate coiled tubing access for intervention requirements. Pilot holes are proposed for the Carboniferous wells in block 2a and 2b to validate the reservoir thickness and optimise placement of the horizontal section. The chemicals discharged during the drilling programme are relatively benign, the majority being risk assessed by the Centre for Environment, Fisheries and Aquaculture Sciences (CEFAS) as hazard quotient (HQ) colour band Gold or Offshore Chemical Notification Scheme (OCNS) category E. These are categories for products that present the lowest hazard to the environment. Furthermore, the majority of the category E chemicals have been classed by OSPAR as posing little or no risk (PLONOR) to the marine environment. A small minority of chemicals will be discharged that have a higher hazard quotient (HQ) (have a greater potential to cause environmental harm), are in an OCNS category indicating that they are potentially more harmful than category E products, or that have been marked as candidates for substitution (SUB) as they contain components that have high toxicity, low biodegradation and/or potential for bioaccumulation. A preliminary list of chemicals to be used during drilling is supplied for reference in Appendix 3. Chemical and drill cuttings discharges are quantified in Section 6.1.2.1 and 6.1.3.5. The exact formulation to be used for each well will be finalised in a PON15B application submitted to the DECC at least 28 days prior to drilling each well. Chemical use will be minimised where operationally possible and all discharges risk assessed via the PON15B process. 5.2.2.4 Cementing Other than driven conductors, casings are cemented into place in all the sections of the well bore down to the interface with the reservoir. As each diameter section of the well bore is finished, sections of metal casing, slightly smaller than the well bore diameter are placed in the hole to provide structural integrity. These are cemented in to place by pushing cement in the space (annulus) between the casing and the borehole. The casings for the slim bore design will comprise: 30 conductor set approximately 100m below the sea bed 13 ⅜" casing set at about 1000m within the Upper Cretaceous (13 ⅝ BOP installation) 9 ⅝" casing set into the top Zechstein ensuring isolation of the Bunter Sand behind casing prior to drilling ahead through any potentially abnormally pressured zones within the Zechstein. This casing point forms the cornerstone of SNS casing design and is adopted by the majority of SNS development wells. 7" liner set across the Zechstein and into the Basal Carbonate sequence and Silverpit. For the contingent large-bore well design the casings will comprise: 30" conductor set about 100m below the sea bed 20" casing set at about 1000m within the Upper Cretaceous (21 ¼ BOP installation) 13 ⅜" casing set into the top Zechstein ensuring isolation of the Bunter Sand behind casing prior to drilling ahead through any potentially abnormally pressured zones within the Zechstein (13-⅝ BOP installation) 9 ⅝" casing set across the Zechstein and into the Basal Carbonate sequence. 7" liner set across the Silverpit. CF00-00-EB-108-00001 Rev C1 Page 44 of 300

The cement fluids are pre-mixed in pits on the drilling rig before being pumped downhole. To minimise the quantities of chemicals pumped down hole, a cement liquid additive system will be used to calculate the volumes of premixed fluid required for the job. It is possible that dead volumes may remain in the pit (up to 30 barrels or 4,770 litres) after the operation, which will be discharged to sea. A maximum allowance of 10% of use tonnage will be discharged to the sea, which includes allowance of small volumes of excess slurry and mix water associated with the cement job and equipment wash up, any tonnage in excess of 10% will be skipped and shipped. A preliminary list of chemicals to be used during cementing is supplied for reference in Appendix 3 and summarised in Section 6.1.2.1. The exact chemicals to be used for each well will be finalised in a PON15B application submitted to the DECC at least 28 days prior to drilling each well. 5.2.2.5 Completion Completions are carried out in order to clean residual drilling fluids from the wellbore either to allow changes in drilling mud or prior to commencing production. In addition operations may be carried out, either as part of the initial completions or subsequently (as a workover) to improve the gas flow from the reservoir rocks. These operations are discussed under Production Assurance below. Full details of all completion and workover chemicals will be included in the PON15B or subsequent PON15Fs for each well. Any discharges to sea will be risk-assessed following the DECC established procedures. OBM clean-up If during detailed well design it is decided that the drilling fluid will switch from OBM to WBM, the wellbore will be cleaned-up to remove residual quantities of OBM from the casing before the WBM is pumped. The clean-up will involve a spacer / detergent mix being circulated in front of the WBM. The interface between the spacer/detergent mix and the OBM will be contained and back loaded for recycling and disposal onshore. The WBM, which may be contaminated with residual quantities of OBM, will be discharged to sea. A permit to discharge brine containing residual OBM will be applied for through the PON15B permit. Volumes will be provided in the PON15B permit application; these cannot currently be confirmed as they are supplier dependent. During the course of operations, GDF SUEZ E&P UK will follow a hierarchy of choices when dealing with contaminated fluid in order to minimise the volume discharged to sea, in line with Oil & Gas UK "Good Practice for Clean-Up Operations" document (OGUK 2006). The well bore clean-up pill, plus any interface containing visible OBM generated during the clean-up will be shipped to shore for disposal. However any wastewater containing no visible OBM generated during clean-up will be discharged into the marine environment. All discharges will be sampled, analysed and reported at the end of the drilling operation. Any residual oils in discharged water are likely to be rapidly dispersed in the water column and broken down through bio-physical weathering processes. If a sheen is observed on the sea surface during wellbore clean-up, this will be reported using a PON 1. General clean-up Prior to bringing the wells into production and after any fraccing operations (discussed below), the wellbores will be cleaned-up to remove sand plugs. Three hole volumes of seawater (approximately 102,000 litres) will be flushed around the well to remove the sand. Sand cleanouts will be performed overbalanced so that hydrocarbon contamination of the seawater does not occur. A final clean-out, to induce flow, will be completed using a mixture of seawater and nitrogen. Approximately three hole volumes of water will be co-mingled with nitrogen gas for this clean-up. Clean-up discharges, following fraccing will also contain some of the returned waterbased frac fluids, which will be discharged to sea under the conditions of the PON15B permit. Production assurance In the first few years of production gas recovery is expected to be by natural depletion drive i.e. the pressure in the reservoir will be sufficient to drive the gas into and up the wellbore without the need for artificial lift or pumps. The completions are therefore designed to optimise the flow of gas. Several different completion methods are required for the Cygnus development due to the size of the field, and the diversity of reservoir type and quality. To maximise hydrocarbon recovery, completion design has taken into consideration flow assurance aspects anticipated by the type of formation fluids and target reservoirs. Three main areas have influenced the design: CF00-00-EB-108-00001 Rev C1 Page 45 of 300

Maximising inflow performance improving the inflow area (e.g., with hydraulic fracture or under-balance perforation) and control of solids production (i.e., from proppant flow back and sand production). Maximising lifting performance selection of the optimum tubing size Minimising well intervention well intervention may be required to maintain the production at optimum levels during well life, however, this can be reduced, delayed or prevented by optimum materials selection, well and reservoir surveillance and the introduction of completion components such as chemical injection lines etc. Two methods for improving production are expected to be utilised at Cygnus: Hydraulic fracturing for wells targeting fault blocks 1 and 2a Standalone screens for wells targeting fault blocks 2b, 3 and 4 where sand control is required Hydraulic fracturing Studies have shown that the Cygnus field would benefit from fracture stimulation (GDF SUEZ E&P UK 2008b). Fracturing (fraccing) is a process used to create fissures that extend from the borehole into the rock formation in order to increase the rate which gas (or alternatively oil or water) can be produced from a tight reservoir formation. Hydraulic fraccing is carried out by pumping a specifically-engineered (generally low toxicity water based) fluid into the well at a rate sufficient to increase the pressure downhole above the fracture gradient of the formation rock, typically forming cracks which extend 100m into the rock and are up to 0.5cm wide. A solid proppant (normally ceramic beads) is added to the frac fluid in order to keep the cracks open after the injection of fluid stops. A successful facing operation will typically allow the well to produce 10% more gas than a normal completion on its own. The main operational phases of hydraulic fraccing are the placement of treatments into the well (pumping the frac fluid and proppant to create the fractures) and subsequent activities to clean out the well bore and flow the well to remove the liquid residues of the treatment. Generally, a frac boat is brought alongside the platform to perform the fraccing operations. If fraccing is performed on Cygnus A, initial well cleanup will be undertaken using temporary equipment prior to switching to the permanent platform de-sanding facilities. Generally a frac boat is brought alongside the platform to perform the fraccing operations. It is expected that Cygnus B wells will not require fraccing. The majority of the frac chemicals and proppant will remain downhole within the fractures. Small quantities will be discharged to sea as the wells start producing. Full details of all completion and frac chemicals will be included in the PON15B for each well. Any discharges to sea will be risk-assessed following the DECC established procedures. Standalone Screens Stand alone screens are non- chemical filters designed to remove particles from the production stream. 5.2.2.6 Well testing and flaring It is possible that the production wells may be flared for testing purposes and/or to clean-up the wellbore. Exact details have yet to be confirmed but the most likely scenario would be 12 hours of clean-up flaring followed by 12 hours of well test i.e., a total of 24 hours of flow for each well. The approximate volume of gas to be flared during the test is likely to be in the order of 26MMscf; i.e., a total of up to 260MMscf if all ten wells are cleaned-up and tested. In the contingent case, there is the requirement to hydraulically fracture up to three wells. In this scenario extended clean-ups/well testing will be required. The clean up and testing of each fractured well is expected to take a maximum of 10 days. The approximate volume of gas to be flared during the clean-up/well testing is likely to be in the order of 260MMscf per well (7.4million m 3 ); i.e., up to 780MMscf (22.1million m 3 ) if all three frac candidate wells are cleaned-up and tested. An application for an extended well test will be submitted to the DECC should it be determined that this contingency is required. CF00-00-EB-108-00001 Rev C1 Page 46 of 300

5.2.3 Pipelines and Subsea Infrastructure The subsea facilities at Cygnus will comprise: 51 km long, 24" gas export pipeline from Cygnus A to the ETS pipeline. 5.9 km long, 12" intra-field gas production pipeline and a control and chemical injection umbilical between Cygnus A and B. Wye manifold to facilitate tie-in between the Cygnus A export pipeline, the Trent spur and ETS pipeline. An SSIV (subsea safety isolation valve) at the Cygnus A end of the export pipeline plus a corresponding SSIV umbilical from PU platform. Two pipeline crossings. 5.2.3.1 Pipeline Specifications As detailed above, the field development consists of three pipelines, the specifications of which are given in Table 5-4. Table 5-4 : Specification of the pipelines Pipeline 24-inch Export 12-inch Production Location Cygnus A to ETS pipeline tie-in Cygnus A to B Length (km) 51 5.9 Design pressure (barg) 139.3 324 Design temperature ( C) 0.5-37.8 50-29.5 Outer diameter (inches) 24 (0.61m) 12 (0.3m) Internal diameter (m) 0.51 0.28 Volume (m 3 ) 10,418 363 The export pipeline will be constructed from carbon steel and coated with three layers of polyethylene anti-corrosion coating. The pipeline will be concrete coated with 85mm thick concrete from Cygnus A to 25km and concrete 50mm thick from 25km to the ETS pipeline tie-in. Cathodic protection will be provided by means of half-shell bracelet sacrificial anodes. Anodes are aluminium zinc indium (Al-Zn-In) based and designed to provide protection to the pipeline for 35 years. The infield pipeline will be similar construction to the export pipeline although it is not anticipatied that it will be concrete coated. The anodes will be connected directly to the pipework at regular intervals along the export pipeline, intra-field production pipeline and umbilical to provide cathodic corrosion protection. The number of anodes and spacing required will be determined during the detailed pipeline design stage. For the purposes of this EIA, it is anticipated that approximately 18 tonnes of anodes will be required. 5.2.3.2 Installation and commissioning Installation and burial of pipelines typically follows the below process: Laid on seabed Flooded with chemically inhibited seawater Trenched into seabed Gauged and hydrotested Tied-in at both ends Leak-tested Dewatered and commissioned CF00-00-EB-108-00001 Rev C1 Page 47 of 300

The intra-field line will be installed in a similar manner although it is likely that the 12 line will be mechanically backfilled. Prior to the pipeline being laid, an intrusive pipeline route obstruction survey will be conducted. The survey vessel will remain on-site for the duration of the installation to provide support to the other construction vessels. The export and intra-field pipelines will be laid onto the seabed ready for trenching. For the export pipeline the S-lay method will be used, whereby pipe is eased off the stern of the vessel as the boat moves forward. The pipe curves downwards from the stern through the water until it reaches the touchdown point on the seafloor. As more pipe is eased off the boat it forms an S shape in the water. The intra-field pipeline will be laid using the reel lay method, where pipe is rolled out from the reel on the back of a reel lay barge. It is expected that the pipelines will be laid either using a dynamically-positioned (DP) pipelay vessel or an anchor lay barge. Each method is described below. Anchor lay-barge A conventional lay barge maintains position through the use of anchors. There will be 8 anchors; four will be placed in front, with two at mid-ships and two at the rear. The mid-ships anchor chains will extend approximately 1km and the stern and aft anchors will extend between 1.5 and 2km. The anchor corridor will therefore be 2km wide. The vessel manoeuvres by shortening the lines to the front anchors and extending those to the rear. Once the maximum length of the rear anchor chains is reached, they are lifted and moved forward. The shortened front anchors are lifted and moved forward and the vessel gradually progresses forward, laying the pipe. It is estimated that approximately 33 pulls will be required for the export pipeline, resulting in 266 anchor placements. The intra-field pipeline will require approximately 34 anchor placements. As described in Section 5.2.1.3, removed anchors are likely to create a mound as sediment is displaced. In addition, the anchor chains have the potential to rest or drag across the seabed surface creating scour marks. Dynamically positioned (DP) Vessel The alternative to an anchor lay barge is a DP vessel, which uses thrusters to position itself over the pipeline route. A typical vessel used for this type of operation has a draft of 6.5m. The housing for the thruster propellers may extend to a maximum of 2m below this depth. The propellers create disturbance in the water column typically to 5m, below which the effects are not discernible from natural currents and wave orbital movements. Therefore the deepest effects from a DP vessel are anticipated to reach down to approximately 14m from the sea surface. At the start of the installation process an initiation anchor (typically a conventional 13½ tonne anchor or similar) will be used to help position the vessel and pipeline in the target box. However, during the installation process the vessel will not use anchors for positioning. Installation Touch-down of the pipelines will be monitored by a ROV. The export and intra-field pipelines will be flooded with chemically inhibited seawater (typically seawater containing oxygen scavenger, biocide and dye) to prevent corrosion, prior to mechanical trenching operations. Figure 5-5 : Typical displacement plough Once flooded, the pipelines will be trenched. The 24" export pipeline to the ETS pipeline will require a single trench and the 12" intra-field pipeline will require a trench for the production line and a trench for the control umbilical. Trenching will be carried out using a displacement plough (Figure 5-5). The plough is towed behind a plough vessel. The plough is in physical contact with the pipeline, which it guides or directs into the trench. The plough will create an open v-shaped trench into which the pipeline is laid. Source: www.ctcmarine.com CF00-00-EB-108-00001 Rev C1 Page 48 of 300

Spoil from the trench is positioned on either side in shallow berms (Figure 5-6). Trenches are likely to be between 2.5m and 6m wide depending on the plough used and the configuration of the plough shares, with spoil heaps up to 3m wide and 2m high, although it is anticipated that the berms will be naturally removed through sediment movements within a short period. A guard vessel will be on-site whilst the pipelines are unburied and will ask fishing vessels to keep at least 500m away from the pipelines on either side. Installation is expected to take place between May and July 2013 for the export pipeline and between July and August 2014 for the intra-field pipelines. Figure 5-6 : Typical trench created by displacement plough Source: Brown and Bransby (2007) The trench will be initiated and terminated 100m from the respective platform and the ETS pipeline tie-in point. The target depth for the trenches will be 3m for the export pipeline and 2m for the intra-field pipeline to allow for 1m burial from the top of the pipes to mean seabed level. The trench depth has been selected based on a consideration of the geotechnical characteristics of the area, the geotechnical site survey and from estimated upheaval buckling criteria. The trench depth selected has been designed to eliminate the need for rock protection; however rock material may be required in problematic areas. It has not been determined whether the pipeline will be mechanically or naturally backfilled at this time. Mechanical backfilling will occur during or after trenching, and will involve a backfill plough will be towed along the route to return the spoil into the trench. Natural backfilling will allow sediments to fill in the trench through normal seabed processes. After backfill the final seabed profile will be a shallow depression over the pipeline due to the loss of finer sediments from displaced material through winnowing. Small residual berms may be present along the routes following either backfill method. Prior to determining whether natural or mechanical backfilling should be undertaken, a further review of BAT and BEP will be completed and modelling of sediment movements will be conducted as appropriate. Concrete mattresses will be laid over the export and intra-field pipelines within the 500m exclusion zones around the Cygnus A and B installations to provide protection, separation and support for the pipelines. Commissioning Once in position the export pipeline will be fitted with a pipeline inspection gauge (PIG) catcher and launcher at the ETS pipeline tie-in and Cygnus A hub ends respectively. The pipelines will then be hydrotested using dyed inhibited seawater by flooding the line from the pig launcher to the pig catcher. The inhibited seawater will be pumped into the pipeline (typically 20% line volume) to build up the pressure until test pressure has been established and stabilised. Test pressure will be held for 24 hours before the pipelines are depressurised, by discharging the extra volume of inhibited seawater to sea, at predetermined rates. After hydrotesting, the pipeline will then be tied-in at both ends. Spools will be installed from the WYE manifold to the ETS pipeline and from the SSIV skid to the Cygnus A platform riser. Once all CF00-00-EB-108-00001 Rev C1 Page 49 of 300

the spools are installed they will be leak tested by pushing dyed inhibited seawater back to Cygnus A. Additional quantities of inhibited seawater pumped into the pipeline to establish leak test pressures will be discharged to sea. On completion of the leak test, the pipeline will be dewatered back to Cygnus. The remaining volumes of inhibited seawater will be flushed out of the pipelines and discharged to sea. The gas pressure will be equalised at the ETS pipeline connection before it is filled with gas from the ETS pipeline. When the line is full of gas, export of gas from Cygnus will start. Exact details of the chemicals to be used during flooding, hydrotesting and leak-test were not available at the time of the ES submission, but all chemicals selected will be CEFAS registered and will be provided in the PON15C for each pipeline as required under the Offshore Chemical (Amendment) Regulations 2011. GDF SUEZ E&P UK will preferentially select chemicals that are environmentally benign and chemical use will be monitored daily. In total, six vessels will be used for pipeline installation and commissioning: Heavy Lift Vessel for WYE and SSIV structure installation Survey vessel Pipeline installation vessel Trenching vessel Dive support vessel Guard vessel Installation and testing of the export pipeline to the ETS pipeline are expected to take 60 days, and is to be undertaken within a six month window. Commissioning of the intra-field pipeline between Cygnus A and B will follow the same process as for the export pipeline. This has been assigned 27 days within the schedule. 5.2.3.3 Tie-in Export Pipeline The Cygnus development will tie in to the ETS pipeline approx 1km from the Trent platform, on the Trent ETS 24" spur line. The ETS pipeline tie-in will be in the form of a piggable WYE manifold (see Figure 5-7) to allow pigging operations to be carried out from both the Trent and Cygnus platforms. CF00-00-EB-108-00001 Rev C1 Page 50 of 300

Figure 5-7 : Cygnus A to ETS pipeline WYE manifold The WYE structure will house the 24 WYE piece and six 24 manual isolation valves as well as other smaller appurtenances. Spool connections will be made between the new Cygnus export pipeline, the Trent ETS spur line and the ETS pipeline to Bacton. The WYE structure is required to protect the valves and associated connections from snagging, making the design fishing friendly. Installation and tie-in of the WYE structure will consist of the following steps: 1) Lifting and positioning in place alongside the ETS tie-in location by an HLV and the installation of four 30 x 1 x 20m long piles for stability purposes. 2) Installation of an isolation PIG using a MEG/ water mix pumped from Trent to a position 100m past the tie-in location. 3) Isolation PIG will be pressure tested to confirm double isolation allowing divers to remove the existing spool. 4) Cut out of the spool from the Trent ETS spur line and ETS pipeline to Bacton. 5) Installation of spools, which will connect the WYE structure with the ETS pipeline. 6) Installation of a temporary PIG receiver at the end of the first spool within the WYE structure (before the WYE). 7) Further leak testing will be conducted, after which the isolation PIG will be deactivated and recovered into the temporary PIG receiver which will be recovered to surface. 8) The valves on the WYE structure will be closed. 9) Spools containing PIGs will be installed between the WYE structure and Trent ETS spur line. 10) A leak test will then be performed to confirm integrity of the final tie-in flanges. 11) After this test is completed gas from the Trent will be used to dewater the 1km liquid isolation train to Bacton. 12) Gas production from Trent will then recommence. 13) Following tie-in of the Cygnus gas export pipeline to Cygnus, gas in the ETS pipeline will be used to dewater the new export pipeline to the Cygnus A PU. 5.2.3.4 Pipeline crossings The Cygnus export pipeline will require two pipeline crossings: 10" Cavendish to Murdoch gas export pipeline, approximately 32km from Cygnus A 20" Tyne to Trent gas pipeline, within 500m of the ETS pipeline tie-in point CF00-00-EB-108-00001 Rev C1 Page 51 of 300

Both pipelines that require crossing are presently buried. As such only a simple pipeline crossing solution is necessary. Concrete mattresses will be placed over the existing pipeline to support, separate and protect the two pipelines. There will be three 300mm thick mattresses centrally over the buried pipeline and three 150mm mattresses either side. The mattresses and pipelines will be surrounded and covered by a gentle sloped, protective rock surround (see Figure 5-9). Both crossed pipelines will remain live during installation which is standard industry practice. Figure 5-7 : Cross section through the Tyne to Trent pipeline crossing Figure 5-8 : Rock deposition by fall pipe over pipeline crossing Trenching will stop a minimum of 60m from approach to the crossing point and will resume at least 60m from the active pipeline. However, the rock protection will extend to 160m either side of the crossing point. Rock will be positioned using a fall pipe vessel (Figure 5-10). An ROV survey will be undertaken to ensure the crossing is sufficiently covered and pipelines are protected. Source: Tideway (2011) CF00-00-EB-108-00001 Rev C1 Page 52 of 300

5.3 PRODUCTION Cygnus gas will be exported to a tie-in on the Perenco operated ETS pipeline. The ETS pipeline landfall is at the Perenco operated Bacton terminal. Current estimates are that the Cygnus field is expected to produce a maximum of 250MMscfd of dry gas for up to 30 years. In order to achieve the required specification for the ETS pipeline, the gas will processed to separate any condensate, remove water and control the temperature. 5.3.1 Process Description The Cygnus facilities are designed to deliver 250MMscfd of dry gas through the ETS pipeline to Bacton along with up to 750bpd of dry condensate. Normal operating pressures are not expected to exceed 95 barg based on the export pipeline system rated pressure of 107 barg. Up to 150MMscfd of wet gas will be produced at Cygnus A. The wet gas will be processed through a dedicated train where the condensate and water will be separated from the gas. Heat will be used to promote the separation of the condensate from the water in a coalescer. The ETS pipeline entry specifications do not require a set water content in the condensate entering the pipeline, however, water removal may be necessary to mitigate corrosion. Up to 150MMscfd of wet gas will also be produced at Cygnus B. Monoethylene glycol (MEG) will be injected into the gas production pipeline to control hydrate formation at Cygnus B. It will then be transferred to Cygnus A in the gas stream. On arrival at Cygnus A, a parallel process train will be used to separate the condensate, water and MEG from the gas. Gas from both the process trains will then flow to the triethylene glycol (TEG) dehydration unit. This unit will remove water from the gas steam to below the pipeline specification of 2.7kg per MMscf of gas. TEG will be heated to regenerate it by removing the water. It will then be reused, minimising raw materials consumption. The condensate separated from both the Cygnus A and B trains will be pumped up to export pressure and transferred onshore through the ETS pipeline with the gas. The MEG/water (rich MEG) separated from the condensate from Cygnus B will be directed to a MEG reclaimer and regenerator which will recover the MEG. The liquid will be heated to 25 C prior to transfer into the reclaimer which uses vacuum distillation to separate the produced water, due to probable contamination with significant levels of salt. The regeneration system will be designed to process 4.3m 3 per hour of 56% MEG. MEG will be regenerated to 90% concentration and returned to Cygnus B via the umbilical for reinjection into the gas stream. The brine residue along with produced water from the Cygnus A process train will then be treated to remove residual hydrocarbons before being sampled, metered and discharged to sea. Condensate from each train will be metered using turbine or coriolis meters before being pumped into the export pipeline. The back pressure at Cygnus will be controlled by the back-pressure imposed on the ETS pipeline from the Bacton terminal. As the wellhead pressure falls, compression from the compression module will be introduced to maintain the export pressure and production rate. The gas will be metered and sampled to pipeline and custody transfer standards. All gas produced from the wells will be exported or otherwise utilised on the platform as fuel gas, with the exception of trace amounts of fugitive gases liberated during the MEG/TEG reclamation/regeneration process and produced water management. 5.3.2 Produced Water Produced water will be separated on both Cygnus A and B using coalescing vessels and degassers. The coalescing vessels and degassers will remove the majority of water entrained within the gas; however, gas transferred from Cygnus B will still contain enough water to be initially classified as wet gas, and require hydrate inhibition within the intra-field pipeline as described above. Consideration has been given to reinjection and other methods of managing produced water, however it is considered that the method selected is in line with the requirements of indicative BAT. Due to the low condensate to gas ratio, large volumes of hydrocarbons in the produced water discharges are not expected (see Section 6.2.2). All produced water discharges will be compliant with OSPAR recommendation 2005/3 i.e., oil in water concentrations <30mgl -1. CF00-00-EB-108-00001 Rev C1 Page 53 of 300

Online oil in water measurement will be in use and regular sampling will be undertaken at Cygnus A. Sampling will be on an opportunity basis at Cygnus B. 5.3.3 Power Generation The concept design stage of the project has identified that the electrical power requirement for Cygnus will be 3.1 MW(e). Main power generation on Cygnus A will be provided by two 3.1 MW dual fuel (gas/diesel) turbine driven generators. A dual fuel system has been selected to provide operational flexibility. Fuel gas used for the turbines will be export gas; any additional fuel conditioning required will be undertaken as appropriate. Table 5-5 presents the estimated rating and efficiency of the equipment. It is anticipated that the power generated by one turbine will be sufficient for the majority of normal operating conditions, therefore the two turbines will be installed in parallel, with one being maintained on standby whilst the other is operational. In instances where both generators are unavailable, a diesel engine can be used. This is significantly smaller (0.8MW) than the main generators and will be used in emergency situations only. Further details of the specification of the equipment will be available once equipment selection has taken place. Small diesel engines will be used to operate the cranes located on QU, PU, WHP platforms and on Cygnus B. The size of the cranes has not yet been engineered, therefore further details of the engines are currently unavailable. It is not considered that these will be large engines and they are unlikely to have a significant impact on the fuel consumption or air emissions from the installation. It is anticipated that wellhead pressure will fall from between 18 and 48 months after first gas, therefore compression will be required to maintain the export pressure and production rate. Two 7MW gas turbine driven compressors will be installed on Cygnus A to provide this service. The fuel gas used will be export gas. It is anticipated that both compressors will be required to operate simultaneously; the system has been designed for operation of both compressors in parallel at 60% capacity however loading will vary depending on production. Table 5-5 : Power generation equipment Equipment Fuel Type of item and primary purpose Expected site rating per item (MWth) 1 Thermal efficiency 3 (%) Approx annual running hours per item 2 x Combustion gas turbine 1 x Diesel engine 3 x Diesel engine 4 x Diesel engine 2 x Combustion gas turbine Gas / Diesel Diesel Diesel Diesel Gas Cygnus A power generation Cygnus A emergency power generation Cygnus A firewater pump 4 Cranes located on QU, PU, WHP and Cygnus B Cygnus A gas compression 3.1 28 4,100 0.8 40 200 0.315 40 100 0.328 40 1,000 7 34.8 8,200 1 The Expected site rating is the project estimate of site load requirements during concept define 2 Each maximum rated power is the project calculated maximum power required and not a driver rating; the specific equipment selection has not yet been undertaken. 3 Thermal efficiencies have been assumed based on typical manufacturers information, with 40% assumed for all diesel engines. 4 Firewater pumps may be reduced to two operating at 100% capacity. CF00-00-EB-108-00001 Rev C1 Page 54 of 300

Emissions from the power generation will be assessed under the Offshore Combustion Installations (Prevention and Control of Pollution) Regulations 2001. An approved PPC permit will be in place prior to production starting. The final specifications for the combustion equipment present on the Cygnus A hub will be made following further engineering assessments. Once the equipment has been specified it will be determined whether the installation will be regulated under the Greenhouse Gas Emissions Trading Scheme Regulations (2005) as amended or any other applicable regulations and the appropriate applications will be made. 5.3.4 Metering The Cygnus A platform will be provided with gas and liquids metering to a fiscal standard prior to export. 5.3.5 Controls Cygnus A will be a permanently manned installation. It will be linked via satellite to onshore Cygnus production personnel with key data sent to a control room in Bacton. Cygnus B will be controlled via Cygnus A, by the subsea control umbilical which will also carry chemicals and power. Cygnus will be designed to accept a shutdown signal from Bacton. 5.3.6 Chemical Management Exact chemical use during production is still to be defined but it likely that the following chemicals will be used: Hydrate inhibition MEG has been selected as the most appropriate substance to prevent the formation of hydrate in the intra-field pipeline. Corrosion inhibitor this is required to protect the intra-field pipeline from the wet gas. An evaluation is currently ongoing to determine the most appropriate corrosion inhibitor solvent carrier. Use of anti-emulsifier or demulsifier will depend on the corrosion inhibitor testing results. Anti-emulsifier or demulsifier this will depend on the corrosion inhibitor testing results Methanol will be used for injection into the wellhead for start up during extended shut-in periods. Scale inhibitor likely to be calcium carbonate or barium sulphate. Injection is required with formation water breakthrough. There is potential for down-hole scale-squeezes where scale inhibitor is squeezed into production zones. Halite scale inhibitors this is added to fresh water to prevent formation of halites. These are likely to include biocide, oxygen scavenger and clay inhibitor. Wax inhibitors only required for the intra-field pipeline during extended shut in and cool down periods. Foaming and anti-foaming surfactant will be required in later field life. The foaming surfactant will be required to extract the gas and the anti-foaming surfactant will be required to neutralise the foaming surfactant within the process trains. Other maintenance chemicals including small amounts of oils and greases. A complete list of chemical use and discharge will be submitted to the DECC in the form of a PON15D application at least two months prior to production operations commencing. Chemical use at Cygnus A and B will be managed in line with the requirements of the Offshore Chemicals (Amendment) Regulations 2011 and GDF SUEZ E&P UK HSE&Q management practices. 5.3.7 Gas Venting and Flaring GDF SUEZ E&P UK is committed to minimising the volume of gas disposed of by flaring and venting. Cygnus A will incorporate a flare boom and have capacity to flare up to 250MMscfd of gas, Cygnus B will only have capacity for venting. Gas will only be flared under the following scenarios: CF00-00-EB-108-00001 Rev C1 Page 55 of 300

Operational or mode changes gas flaring as a result of start up and planned shutdown, offspecification gas, maintenance and equipment outages. Emergency shutdown and process trips gas flaring required as part of an emergency shutdown or process trip including shut-in of the wells. Cygnus A and B will also incorporate venting unignited hydrocarbons and inert gases. This is generally discharged via atmospheric vents and may include off-gases from the MEG/TEG regeneration units and the produced water degasser. It is estimated that this will be less than 200m 3 of gas per day. GDF SUEZ E&P UK will seek to minimise flaring and venting to as low as reasonably practicable (ALARP) by implementing BAT and BEP in the design development and by continuing to improve on this during operations. Consideration will also be given to good practice when reviewing plant uptime, efficient processing, handling, use and transportation of gas. 5.3.8 Drainage Cygnus A will have closed and open drainage systems to ensure that containment is provided where hydrocarbon spillage could occur. 5.3.8.1 Non-hazardous drains Deck drains from the non-hazardous areas will be collected by the non-hazardous open drains system, which will route all liquids to a common overboard discharge line or to overflow lines which discharge directly offshore. 5.3.8.2 Hazardous drains The hazardous drains will collect hydrocarbons from various points in the process system and liquids drained from process plant during maintenance. Hazardous drains will also collect fluid from open drains within hazardous classified areas. The collected liquid will be treated to remove hydrocarbons, prior to discharge of the water overboard. It will also be possible to transfer the collected liquids to tote tanks for shipment to shore for treatment and disposal by a licensed waste contractor. 5.3.9 Sewage system Under the Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008 which implement in the UK the requirements if MARPOL 73/78 Annex IV a fixed platform is defined as a ship. The Regulations prohibit the discharge of untreated sewage within 12 miles of the coastline. However, there are no Regulations that prevent untreated sewage being discharged outside of this area, and as such Cygnus A could legally discharge sewage. Given the shallow water depth at the project site and the longevity of the field GDF SUEZ E&P UK are currently considering sewage treatment options. Where possible they will endeavour to follow industry best practice for the region. 5.3.10 Maintenance 5.3.10.1 Platforms The central Cygnus A platform will be a manned installation with normal access by helicopter. Maintenance will be incorporated into the GDF SUEZ E&P UK Asset Maintenance and Integrity Management Systems; preventative maintenance and inspection will therefore be undertaken in line with the requirements of indicative BAT. All equipment that will require regular maintenance will be easily accessible. The Cygnus B NPAI will be accessed by helicopter for regular maintenance visits. The installation will be designed to allow for quick maintenance. Generators on Cygnus B will be self contained for simple replacement in case of failure and all spare machinery will allow for remote/automatic changeover without platform attendance. All equipment that will require regular maintenance will be easily accessible without the need to use temporary ladders or scaffolding. Accommodation on Cygnus B will be suitable for extended visits to support maintenance activities. The key equipment will be visually monitored remotely from the Cygnus A platform by CCTV coverage. CF00-00-EB-108-00001 Rev C1 Page 56 of 300

5.3.10.2 Pipelines The export pipeline will require regular operational sphering or equivalent to remove slugs of liquids and keep the pipeline clear; the tie-in with the ETS pipeline has been designed to allow for this. The export and intra-field pipeline designs will both be suitable for inspection pigging for routine general (inline) inspection surveys to check for spans and integrity issues. It is anticipated that the export and intra-field lines will be inspected every five years. 5.4 DECOMMISSIONING It is anticipated that operations will cease between 2024 and 2038 depending on reservoir performance, economic variable and the potential for tie-back to the facilities from other developments. Decommissioning will be carried out in accordance with all applicable United Kingdom and international legislation and practices at the time. At cessation of operations, the Cygnus owners will decommission the facilities and the intra-field pipeline. Consent for Cessation of Production will be sought in advance and an Abandonment Safety Case will be prepared and submitted to the HSE. The information supplied prior to decommissioning the facilities will be stipulated by the regulatory authority at the time, however it is likely to be similar to current requirements. This will involve a Decommissioning Programme, a comparison of available options including risk assessment and an EIA as appropriate. Currently, under OSPAR Decision 98/3, which has been accepted by UK Government, the disposal at sea and the leaving wholly or partly in place of disused offshore installations is prohibited. It is likely that the following activities will therefore be undertaken as part of the decommissioning programme: Plug and abandon all wells Remove conductors to below the mud line Remove all subsea infrastructure e.g. well heads and pipelines Third party confirmation of seabed clearance Remove platforms for reuse or recycling onshore It is likely that under the legislation a case will be made to allow the pipelines to be left in-situ, as long as it is considered to comply with the requirements and there are no health, safety and environmental issues associated with this activity (DECC 2011). Removal of the pipelines would cause disturbance of the seabed which upon the estimated period of decommissioning will have been in place for between 13 and 24 years, should have returned to pre-installation baseline conditions. Under current legislation decommissioning requires an EIA to be conducted prior to activities commencing. The EIA would assess the benefits and costs of different decommissioning scenarios i.e., removal versus remaining in-situ. The impacts of decommissioning activities on the environment have not been assessed under the scope of this document as they will be the subject of a separate EIA. 5.5 PROJECT ACTIVITY SUMMARY In conclusion, certain aspects of the project activities described in the above section have the potential to interact with the environment. These project aspects are detailed in Table 5-6 and their interaction with each environmental receptor have been assessed in Sections 8 to 10. CF00-00-EB-108-00001 Rev C1 Page 57 of 300

Table 5-6 : Summary of project activities and aspects Construction Project Activity Physical presence and movement of transportation Drilling of wells Installation of infrastructure Production Presence of platform Physical presence and movement of transportation Power generation Produced water Maintenance of platforms, pipelines and wells Gas venting Flaring Accidental Events Spill of chemicals or hydrocarbons (<1 tonne) Spill of chemicals or hydrocarbons (>1 tonne) Overboard loss of equipment or waste Project Aspects Physical presence / exclusion zones Positioning structures on seabed e.g., jack-up legs, anchors Exhaust gas emissions Discharge of sewage, grey water, food waste & drainage water Subsea noise Use of thrusters in shallow water Flaring of gas Subsea noise Discharge of chemicals (including WBM) Discharge of cuttings Discharge of reservoir hydrocarbons Subsea noise Trenching Discharge of chemicals Cathodic protection on pipelines Concrete mattressing and rock material Positioning structure on seabed e.g., platform piles, wye manifold, valves skids Physical presence / exclusion zones Discharge of sewage, grey water, food waste & drainage water Emission of light Exhaust gas emissions Subsea noise Discharge of sewage, grey water, food waste & drainage water Physical presence Exhaust gas emissions Discharge of reservoir hydrocarbons Discharges of chemicals Release of gas Release of combustion gases Chemical, diesel or condensate spill Dropped objects CF00-00-EB-108-00001 Rev C1 Page 58 of 300

6.0 PROJECT FOOTPRINT This section, as for the project description, is presented in two main parts: Construction and Production operations. For each stage, a quantitative, where possible, and a qualitative summary of the environmental footprint of the project on the following key environmental receptors is provided: Atmosphere Water resources Seabed The project footprint includes the physical presence of the project on the surrounding environment (e.g., drill cuttings, anchor scars and pipeline trenching on the seabed) and emissions to air and water (e.g., greenhouse gas emissions to the atmosphere, chemical and wastewater discharges to sea and noise pollution to air and sea). 6.1 CONSTRUCTION 6.1.1 Atmosphere 6.1.1.1 Exhaust gas emissions During construction, a number of vessels and aircraft will be used for a variety of construction activities. Each vessel/helicopter will generate atmospheric emissions from the combustion of fuel. Estimated emissions are summarised in Table 6-1. Estimates for vessels are based on the maximum number of days vessels will be on-site and the worst-case fuel use during construction activities in that period. Table 6-1 : Construction exhaust gas emissions Activity Vessel Types Duration (days) Total Fuel Use (tonnes) Total Emissions (tonnes) CO2 CO NOx N2O CH4 VOC SOx Drilling Drilling rig 1,214 8,498 27,194 68.0 501.4 1.9 22. 9 Standby vessel Anchor handling vessel 20.4 17.0 1,214 2,428 7,770 19.4 143.3 0.5 6.6 5.8 4.9 24 600 1,920 4.8 35.4 0.1 1.6 1.4 1.2 Supply boats 347 3,470 11,104 27.8 204.7 0.8 9.4 8.3 6.9 Pipeline Trencher 60 605 1,935 4.8 35.7 0.1 1.6 1.5 1.2 Export pipeline Intrafield pipeline Dive support / multi service vessel (MSV) 80 1,200 3,840 9.6 70.8 0.3 3.2 2.9 2.4 Survey vessel 75 1,125 3,600 9.0 66.4 0.2 3.0 2.7 2.3 Guard vessel 145 290 928 2.3 17.1 0.1 0.8 0.7 0.6 Supply boats 46 460 1,472 3.7 27.1 0.1 1.2 1.1 0.9 S-lay vessel 40 672 2,150 5.4 39.6 0.1 1.8 1.6 1.3 Reel-lay 20 168 538 1.3 9.9 0.0 0.5 0.4 0.3 vessel 1 CF00-00-EB-108-00001 Rev C1 Page 59 of 300

Activity Vessel Types Duration (days) Total Fuel Use (tonnes) Total Emissions (tonnes) CO2 CO NOx N2O CH4 VOC SOx Platform Heavy lift vessel Temporary accommodati on vessel 20 140 448 1.1 8.3 0.0 0.4 0.3 0.3 90 630 2,016 5.0 37.2 0.1 1.7 1.5 1.3 Transfer Helicopter 51.5 66 207 0.3 0.8 0.01 0.0 1 Pipelay Option 1 Pipelay Option 2 Anchor lay barge 0.1 0.13 40 1,000 3,200 8.0 59.0 0.2 2.7 2.4 2 Four tugs 40 280 896 2.2 16.5 0.1 0.8 0.7 0.56 DP lay vessel 40 1,280 4,096 10.2 75.5 0.3 3.5 3.1 2.56 Total (including Pipelay Option 1) 21,632 69,218 173 1,273 5 58 52 44 Total (including Pipelay Option 2) 21,632 69,218 173 1,273 5 58 52 44 1 Either a reel-lay vessel or a J-lay vessel may be selected for the intra-field pipe laying however the reel-lay vessel has the higher emissions during construction operations and has therefore been used for the purposes of the assessment. 6.1.1.2 Well testing As described in Section 5.2.2.7 the production wells may be flared to clean-up and test the reservoir. It is estimated that approximately 26MMscf of gas over 24 hours will be flared per well; 260MMscf if all ten wells are tested. The maximum emissions that can be expected are given in Table 6-2. Table 6-2 : Total emissions resulting from well testing (tonnes) Emission Emissions for 1 well Emissions of 7 wells Emissions for 10 wells CO2 1,987.85 13,914.97 19,878.53 CO 4.76 33.30 47.57 NOx 0.85 5.96 8.52 NO2 0.06 0.40 0.58 SO2 0.01 0.06 0.09 CH4 31.95 223.63 319.48 VOC 3.55 24.85 35.50 Note 1: Emission factors taken from Table 10-1 in Root-5 Ltd (2004). Note 2: A gas molecular weight of 21.6 has been used based on Cygnus field gas composition data. Note 3: Emissions for 7 wells have been presented because if the contingency case, described below is undertaken, 3 wells will require an extended well test rather than a normal well test. If the contingency case is undertaken, three wells will be hydraulically fractured requiring extended well tests. The clean up and testing of each fractured well is expected to take a maximum of 10 days. The emissions for these well tests are presented in Table 6-3. CF00-00-EB-108-00001 Rev C1 Page 60 of 300

Table 6-3: Total emissions resulting from well testing conducted on hydraulically fractured wells (tonnes) Emission Emission for 1 well Emissions for 3 wells CO2 19,878.53 59,635.59 CO 47.57 142.71 NOx 8.52 25.56 NO2 0.58 1.74 SO2 0.09 0.27 CH4 319.48 958.44 VOC 35.50 106.5 6.1.1.3 Total emissions to air During construction the combination of exhaust gases from vessels and well testing will release the following (maximum) emissions to air: Carbon dioxide (CO2): 142,769 tonnes Oxides of nitrogen (NOx): 1,305 tonnes Oxides of sulphur (SOx): 44.33 tonnes 6.1.1.4 Airborne noise Few data sources are available for airborne noise levels offshore. It is acknowledged that wave and surf noises are important contributors. It is expected that ambient noise levels will be in the region of 72 to 90 db (re 1µPa) (Richardson et al. 1995). Airborne noise will be generated during all phases of construction. The potential airborne noise sources from construction are summarised in Table 6-4. Table 6-4 : Summary of construction airborne noise sources and activities Activity Source Source type Duration Platform installation Piling Impulsive Transient Pipe-laying and trenching Vessel manoeuvring (positioning drilling rig, transporting equipment and personnel) Trenching and pipe laying vessels and support Deployment and adjustment of anchors Helicopters Support vessels: propellers and bow and stern thrusters Continuous (hours, days, weeks) Drilling Machinery noise Permanent (months) Airborne sound propagation is affected by the proximity of the sound source to the ground or sea level. Vertical propagation is influenced by reflections and wave transmissions across the surface and wind refraction and temperature gradients which produce poor sound transmission in the upwind direction and enhances sound transmission downwind. Although airborne noise is an important issue the main receptor affected offshore is humans. The impacts on human health are addressed through occupational health assessments, mitigation, and regulations and are outside of the scope of this EIA. CF00-00-EB-108-00001 Rev C1 Page 61 of 300

6.1.2 Water Resources 6.1.2.1 Chemical discharges - wells A summary of the chemicals which are expected to be used and discharged during the planned ten well drilling campaign is presented in Table 6-5. The chemicals in this table are based on previous experience of drilling wells in this area. The information provided assumes drilling of ten slim-bore wells. Exact details of the chemicals to be used and discharged during the drilling of individual wells will be provided in individual well PON15B applications. CF00-00-EB-108-00001 Rev C1 Page 62 of 300

Table 6-5 : Summary of anticipated chemical use and discharges from all wells (slim-bore) (tonnes) Ten wells Three wells Drilling: WBM Option Drilling: OBM Option Cementing Completion & Other Frac Chemicals Use Discharge Use Discharge Use Discharge Use Discharge Use Discharge HQ A - - - - - - - - - - B - - 31,900 0 - - - - 76.8 38.4 C - - - - - - - - - - D - - - - - - - - 5.7 3 E 120,660 120,660 73,500 0 25,613 3,376 31,495 30,355 3,860 1,944 Gold 2,105 2,105 1,080 0 1,656 248 670 430 3,963 3,887 Silver - - - - - - 0.5 0.5 - - Total 1,227,650 1,227,650 106,480 0 27,269 3,624 32,166 30,786 7,906 5,872 Label PLO 1,211,200 1,211,200 53,020 0 25,613 3,376 30,460 30,320 964 496 SUB 120 120 33,150 0 594 92 241 0.5 3,911 3,861 CF00-00-EB-108-00001 Rev C1 Page 63 of 300

6.1.2.2 Chemical discharges - pipelines As discussed in Section 5.2.2.3 chemicals will be discharged to sea during various stages in the pipeline installation and commissioning activities. A summary of the expected discharge quantities is provided in Table 6-6. It should be noted that these are based on engineering calculations and are likely to change. Exact details of the chemicals to be used were not available at the time of submission, but will be provided in the PON15C for each pipeline as required under the Offshore Chemical (Amendment) Regulations 2011. For these types of operation seawater is usually inhibited with a dye and a corrosion inhibitor. Table 6-6 : Summary of pipeline discharges Activity Discharge Fluid Discharge Location Pipeline Volume Discharged (m 3 ) Flooding Hydrotesting Leak-testing Commissioning Inhibited Seawater Inhibited Seawater Inhibited Seawater Inhibited Seawater Seabed 24-inch Export 2,084 12-inch intra-field 70 Seabed 24-inch Export 2,084 12-inch intra-field 70 Seabed 24-inch Export 2,084 12-inch intra-field 70 Sea Surface 24-inch Export 12,502 12-inch intra-field 422 Total - - - 19,386 6.1.2.3 Waste water In practice, most construction vessels will be on site for a limited period and it is more likely that they will retain any waste onboard and unload it in port. However, for the purposes of this assessment it has been assumed that all vessels could potentially discharge grey water (from washing and laundry facilities etc) and sewage at site. Table 6-7 gives an estimation of these discharges. CF00-00-EB-108-00001 Rev C1 Page 64 of 300

Table 6-7 : Total waste water discharge (m 3 ) during construction Construction phase Vessels Number of people Duration (days) Grey water (m 3 ) 1 Sewage (m 3 ) 1 Drilling Drilling Rig 88 1214 16024.8 7478.2 Standby Vessel 12 1214 2185.2 1019.8 Anchor handling vessel 15 24 54.0 25.2 Supply boat 30 347 1561.5 728.7 Pipelines Pipeline trencher 110 60 990.0 462.0 DSV / MSV 150 80 1800.0 840.0 Survey Vessel 150 75 1687.5 787.5 Guard vessel 5 145 108.8 50.8 Supply boats 20 46 138.0 64.4 S-lay vessel 250 40 1500.0 700.0 Reel lay vessel 130 20 390.0 182.0 Platform Heavy lift vessel 145 20 435.0 203.0 Pipelay Option 1 Pipelay Option 2 Temporary accommodation vessel 100 90 1350.0 630.0 Anchor lay barge 250 40 1500.0 700.0 Tugs x 4 80 40 480.0 224.0 DP lay vessel 150 40 900.0 420.0 Total (including Pipelay Option 1) 30204.8 14095.6 Total (including Pipelay Option 2) 29124.8 13591.6 1 Estimates based on 150 litres of grey water per person per day and 70 litres of sewage/black water per person per day. 6.1.2.4 Underwater noise As discussed in Section 6.1.1.3, there are a number of potential sound sources during construction activities. The characteristics of underwater noises expected to be produced during the development are shown in Table 6-8 and a summary of the expected underwater noise sources is provided in Table 6-9. Sound is attenuated as it propagates through the water. The local oceanographic conditions will affect both the path of the sound into the water column and how much sound is transmitted. The main environmental receptors affected by underwater noise are fish and marine mammals. Sections 9.3 and 9.5 of this document include an assessment on the disturbance ranges created by the source activities listed below. CF00-00-EB-108-00001 Rev C1 Page 65 of 300

Table 6-8 : Summary of construction underwater noise sources and activities Activity Source Noise generation process Duration Platform installation Piling Impact Hours Pipe-laying and trenching Subsea Installation Vessel manoeuvring (positioning drilling rig, transporting equipment and personnel) Trenching and pipe laying vessels and support Deployment and adjustment of anchors Diver and ROV installation of subsea spools and concrete mattressing Support vessels: propellers and bow and stern thrusters Cavitation / Machinery Weeks Drilling Machinery noise Months Subsea monitoring and repair Conductor driving Impact Hours ROV, Sonar Tonal Days Table 6-9 : Summary of underwater noise produced during construction activities Source Sound Pressure Levels (SPL) of underwater noise * (db re 1μPa @ 1m) (predominant frequency if known) Median Ambient Level 80 to 100 (1 - > 30,000 Hz) Drilling from jack-up rig 120 to 130 Tug / Barge 140 to 170 Trenching 159 to 174 (500Hz) Piling and conductor driving 237 (4kHz) Supply / Support Vessel 160 to 170 (100 to 1000Hz) Helicopters (various) & at various altitudes 101 to 109** * Most data taken from 1/3-octave band centre frequencies (50-2,000Hz) ** Measured at the water surface Source: WDCS (2004), Richardson et al. (1995) 6.1.2.5 Exclusion zones A 500m exclusion zone will be established around the drilling rig to ensure the safety of the vessel during drilling. This will exclude vessels from 0.78km 2 of sea for the duration of the construction period i.e., 1,214 days. The exclusion zone will move with the drilling rig. There is no formal exclusion zone around a pipeline installation. However a guard vessel will patrol the pipeline routes during pipeline installation whilst it is laid out but not trenched. Should it be determined that the pipeline will be mechanically backfilled, the guard vessel will also be present whilst this operation is undertaken. Fishing vessels will be asked to keep 500m away from the pipeline on either side. Depending on the installation schedule the vessel may be on station for anywhere between 15 days to four months. GDF SUEZ E&P UK expects the installation of the export pipeline to take place between April and July 2013 and the installation of the inter-field pipeline to take place between July and August 2014. CF00-00-EB-108-00001 Rev C1 Page 66 of 300

6.1.3 Seabed Conditions 6.1.3.1 Platforms As described in Section 5.2.1.3 all the platforms at Cygnus A and B will be jacket configurations. The estimate of the seabed footprint provided in Table 6-10 is based on the dimensions of the jacket. However, it should be noted that this estimate is conservative. In reality the base will not be a solid but will comprise legs and bracing struts. Table 6-10 : Cygnus platforms seabed footprint (m 2 ) Platform Dimensions (m) Total (m 2 ) Cygnus A Wellhead (W) 25 x 22.5 562.5 Cygnus A Process & Utility (PU) 25 x 40 1,000.0 Cygnus A Utilities and Living Quarters (UQ) 20 x 20 400.0 Cygnus B NPAI 27.5 x 25 687.5 Total - 2,650 6.1.3.2 Heavy lift vessel The heavy lift vessel will have twelve anchors, each with an expected seabed footprint of less than 24m 2. As discussed in Section 5.2.1.3, it is expected that anchor mounds will be created by the spread. The horizontal extent of each anchor mound has been estimated to be 10-15m. Assuming each anchor disturbs a circular area 15m in diameter, the spread will have a seabed footprint of 2,124m 2. For platform installation the heavy lift vessel will be placed in four separate locations at Cygnus A and B. The maximum seabed footprint is therefore estimated to be 8,496m 2. 6.1.3.3 Spud can footprints (jack-up drilling rig and accommodation vessel) Both the jack-up rig and the accommodation vessel have support legs that raise the vessels above the sea surface. As discussed in Section 5.2.2.1 the legs terminate in a spud can, which will leave a depression in the seabed. Typically a jack-up rig has three legs and an accommodation barge four. For this assessment it has been assumed that the spud can dimensions for the accommodation vessel are similar to the jack-up rig and will leave a similar footprint. The jack-up rig has spud cans with a seabed footprint of 314m 2 per can. However, it is expected that the spud cans on the accommodation vessel will be smaller, in the order of 24m 2 per can. Both vessels will be positioned twice at Cygnus A and once at Cygnus B. Based on the soil profile for the Cygnus A site, the spud cans are expected to penetrate 4 5m into the seabed. On removal they will leave a depression similar to those created by the Noble Ronald Hoope at Cygnus appraisal well sites 44/12a-C and 44/12a-D. Post-drilling surveys at these sites indicated that for a spud can with an approximate footprint of 138m 2 (414m 2 for three spud cans) the depression created per spud can was between 1,890m 2 and 1,928m 2 with a depth of around 1m 1 (Gardline Geosciences Ltd 2009b). As the proposed jack-up rig has larger spud cans it is estimated that each depression created could be in the region of 4,000m 2. Therefore the potential footprint for spud can depressions, assuming the vessels cannot re-use existing footprints on return to Cygnus A is: Accommodation vessel at Cygnus A and B 2 : maximum of 3,852m 2 Jack-up rig at Cygnus A and B: maximum of 36,000m 2 However, the footprint of the spud cans will vary due to weight, soil type and the shape of the spud cans. The actual footprint can be calculated more accurately once the first well is drilled and the relevant post-drilling bathymetric surveys have been undertaken. 1 The large footprint in relation to the dimensions of the spud cans was thought to be a consequence of scour. 2 Assumes the depression created will be one sixth of those observed for the Noble Ronald Hoope CF00-00-EB-108-00001 Rev C1 Page 67 of 300

6.1.3.4 Stabilisation rock placement Given the sites history for scour issues (as discussed in Section 5.2.2.2) it is likely that stabilisation material around the spud cans will be required. In general, the spud cans for accommodation vessels do not tend to penetrate as far as those on drilling rigs and scour is less of an issue. However, for the purposes of a worst case assessment, it has been assumed that a maximum of 3,000 tonnes of rock will be placed on the seabed around the spud cans per site. The potential impact from rock placement around the spud cans can be estimated from experience at the Cygnus appraisal well sites 44/12a-C and 44/12a-D. Post-drilling surveys (Gardline Geosciences Ltd, 2009b/c) undertaken at these wells provided quantitative values of the rig stabilisation footprints. On average the material surrounding each spud can covered 1,200m 2. It can be assumed that stabilisation material required for the accommodation vessel would have a similar footprint around each spud can. Therefore the potential footprint for stabilisation material, assuming the vessels cannot re-use existing footprints on return to Cygnus A, is: Treatment of spud cans on accommodation vessel at both Cygnus A and B = 14,400m 2 Treatment of spud cans on jack-up drilling rig at both Cygnus A and B = 10,800m 2 The total seabed footprint is estimated to be 25,200m 2 6.1.3.5 Drill cuttings Table 6-11 summarises the weight of cuttings to be generated from each well and the discharge manner. Exact cuttings weights will be provided in individual PON15Bs for the wells. In order to ensure the worst case scenario is presented it has been assumed that the contingency options have been undertaken. This includes: Drilling of the top section resulting in discharge at the seabed rather than use of a driven 30" conductor with discharge of cuttings 1m below sea level Two wells being large-bore designs which incorporate a 26" WBM section that is discharged 1m below sea level and a 17 ½" OBM section which is skipped and shipped. Table 6-11 : Weight and discharge fate of drill cuttings Well Weight of cuttings (tonnes) Discharged to seabed 1 Discharged 1m below sea level Skipped and shipped Calculations for individual wells 1 well (slim-bore) 103 520 396 1 well (large-bore) 103 1,105 696 Calculations for field development Cygnus A 5 wells (4 slim-bore and 1 large-bore) Cygnus B 5 wells (4 slim-bore and 1 large-bore) 515 3,185 2,280 515 3,185 2,280 Total 1,030 6,370 4,560 Cuttings piles In the event that the top section is drilled (rather than hammered to the required depth), cuttings will be discharged directly on the seabed where they will form a deposition pile around the wellhead. Under conditions of low current speed it is assumed that this pile would form in the shape of a cone. The worst case slope of the angle will be approximately 18 (i.e. a height-to- CF00-00-EB-108-00001 Rev C1 Page 68 of 300

radius ratio of 1:3; the cone will be six times wider than it is high) as this assumes the sand particles to be smooth spheres and does not consider the cohesive effects of particle surface roughness, shape or chemicals (Jumars 2010). It is likely that bottom currents will rapidly resuspend and mobilise the cuttings, spreading them over a larger area. In addition, as the associated WBM dissolves, the cuttings will lose cohesion and spread out. With this in mind the extent of a cuttings pile, still assuming it will take the shape of a cone, has been calculated for a range of slope angles. Figure 6-1 illustrates that a drill cuttings pile with a volume of 52m 3 (103 tonnes), will have a maximum footprint on the seabed of 631m 2. The diameter of the pile would be 28.4m, centred on the wellhead. In reality, it is likely that the footprint will be a lot less, possibly in the range of 90-250m 2. Drill cuttings piles from the 10 wells overlap substantially and thus occupy an area significantly less than if the well sites were completely independent (where the worst-case seabed footprint would be 631m 2 ). Moreover, this footprint will be within the area disturbed by the deposition of cuttings from the sea surface (see below) and thus has not be used in the final calculation of the development footprint. Figure 6-1 : Area of seabed covered by development well cuttings piles Cuttings dispersion following surface discharge Cuttings and sweepings from the sections drilled with WBM will be discharged 1m below the sea surface and therefore will be dispersed over a wider area of seabed as currents transport them away from the discharge point. The pattern of drill cuttings deposition from the rig is expected to be similar to that experienced from other wells drilled in the SNS. A series of cuttings models (e.g. Block 44/12 Cygnus (Gaz de France Britain 2005), Block 44/17 Errol (Conoco (UK) Limited 2000), Block 44/17b Monroe and Topaz (Gaz de France Britain 2004a), Block 44/19 Emerald (Wintershall 2006), Blocks 43/19a & 43/20b Cavendish Area Development (RWE Dea UK 2004), Block 44/23b K3 (ConocoPhillips (UK) Limited 2005a), Block 44/22a Murdoch K (Conoco (UK) Limited 2000) have been undertaken for wells drilled in the SNS and in general, similar patterns of deposition were observed. Cuttings are deposited in an elliptical orientation along the major axis of current flow (generally NW/SE in the SNS). Deposition of cuttings over a thickness of 1mm is generally confined to within 500m of the discharge location. Although no specific modelling has been undertaken for the dispersal of surface discharged cuttings from the Cygnus development wells, their fate, with respect to thickness deposited on the seabed, can be inferred from modelling undertaken at sites close by. Cuttings dispersal modelling was undertaken for the Cygnus exploration well (44/12-2) drilled in 2005 (GDF Britain 2005). The exploration well is located approximately 4km southwest of the proposed Cygnus A location in water depths of 20m. The PROTEUS model was used to simulate the dispersion of 1,342 tonnes CF00-00-EB-108-00001 Rev C1 Page 69 of 300

of cuttings and WBM. Results from the model predicted that an area of approximately 440m by 960m, centred on the well would be covered with cuttings to a depth of 0.5mm. Deposits greater than 2mm in depth were predicted up to a maximum of 145m from the discharge location. The maximum predicted thickness of cuttings was 6mm directly beneath the discharge location. In addition, MIKE 21, which is widely considered to be one of the most technically proficient and robust modelling suites available, was used to model a discharge of 1,214 tonnes of cuttings 1m below the sea surface whilst drilling the three Cavendish development wells (RWE Dea UK 2004). The Cavendish development is sited in 18m water depth on the sand bank feature in the Dogger Bank csac, approximately 38km to the south west of the Cygnus A proposed location. As will be the case at Cygnus, the Cavendish wells were drilled consecutively with at least a month between the end of drilling one well and the start of the next. The Cavendish model considered the deposition pattern resulting from one well, and then estimated the worst case effects of drilling the wells in close proximity by multiplying the deposition thicknesses generated, by the number of wells to be drilled (three). A discharge of 1,214 tonnes of cuttings and mud was modelled for each well. The model indicated that the following could be expected at the Cavendish site: One well Deposits with a thickness greater than 1mm (up to a maximum of 349mm) are likely to extend over an elliptical area of up to 375m by 200m i.e., 75,000m 2 (RWE Dea UK 2004). Patchy deposits of fine material, less than 1mm in thickness, are likely to exist at greater distances from the well. Deposits of mud and cuttings with thicknesses between 1mm and 0.001mm are likely to cover an area of 9.2km by 6km. In practice these are unlikely to be distinguishable from existing sediments (RWE Dea UK 2004). Three wells The extent of deposits greater than 1mm in depth is likely to increase to 950m by 400m with maximum thicknesses of 1,047mm (RWE Dea UK 2004). Patchy deposits (possibly undetectable above background levels) of fine material less than 1mm in thickness are likely to cover an area 10km by 6.3km (RWE Dea UK 2004). The quantities of discharged cuttings modelled for each well at Cavendish (1,214 tonnes) are approximately twice the expected quantities to be discharged from any one small bore well at Cygnus (623 tonnes (51%)) or similar to this from a large-bore well (1,208 tonnes) (see Table 6-11 above). As cuttings fall through the water column they will be affected by the local oceanographic conditions and transported horizontally before they settle on the seabed. Considering that conditions are similar at Cavendish and Cygnus it can be assumed that cuttings will be transported over similar distances before they settle out. The volume of cuttings discharged will, however, affect the thickness of any deposits. Considering that approximately half the quantity of cuttings modelled at Cavendish will be discharged from each slim-bore Cygnus well, it is predicted that deposition depths will be about half those predicted by the Cavendish model. If it is the case that two large-bore designs are used, cumulative deposition depths will be 60% of those predicted by the Cavendish model. The Cavendish and Cygnus exploration well models predicted similar results for cuttings dispersion. The results have been extrapolated to the Cygnus A and B sites and are illustrated in Figure 6-2. It is likely the pattern of cuttings deposition at Cygnus A and B will be similar to those predicted by the models, but deposits are likely to be substantially thinner. Although five wells will be drilled at each Cygnus site, the wells will each take 90 days to be drilled and completed, with substantial intervals between them. The experience of other operators in the SNS indicates that, as a result of the strong currents in the region, cuttings can fully disperse within two weeks of drilling operations completing (see Section 8.4.4 for more details). Thus it is unlikely that cuttings deposits from surface discharges will accumulate at either site. Figure 6-2 suggests that the dispersed cuttings from Cygnus A and B could overlap. However, the depths of the deposits from either site within the overlap area are thin (1 to 10mm, based on the modelled cutting quantities) and drilling operations at the two sites will not take place at the same time, allowing dispersion of deposits. Therefore it is likely that there will be no significant accumulation of deposits from the two sites. It has been assumed that the pattern of deposition at Cygnus will be similar to that modelled for Cavendish. However, as the volume of cuttings arising if eight slim-bore and two large-bore wells CF00-00-EB-108-00001 Rev C1 Page 70 of 300

are drilled at Cygnus is 60% of the discharge modelled for Cavendish it is likely that the area receiving cuttings to a depth greater than 1mm will be correspondingly less, i.e. 45,000m 2 rather than 75,000m 2. As cuttings will be discharged from two locations the footprint at each location will be 22,500m 2. 6.1.3.6 Pipelines Table 6-12 summarises the seabed footprint of pipeline installation activities for the export pipeline and the intra-field pipelines. The width of the trench and associated berms has been assumed based on the largest machine that can be supplied by the contractor. Table 6-12 : Summary of pipeline installation footprint on the seabed Activity Comments Length (m) Width (m) Number Footprint on seabed (km 2 ) Option 1: Pipeline installation using anchor lay barge Lay barge anchors Trench Concrete mattressing Pipeline crossing As anchor type is not known dimensions are based on observations of AC-14 anchor mounds in medium to dense sand reported in BMT Cordah Ltd (2006) Width given is estimated corridor of impact including profile of trench, spoil piles & disturbed area in between - 266 0.0059 34 0.00075 Export 51,000 21 1 1.071 5,900 21 2 0.248 Includes 25% contingency 6 3 260 0.00468 Rock protection covering concrete mattressing: Cavendish to Murdoch and Trent to Tyne 320 10.5 2 0.00672 Option 1: Total 1.337 Option 2: Pipeline installation using DP vessel DP Initiation anchoring Trench Concrete mattressing Pipeline crossing One 13.5 tonne initiation anchor used 5 4 2 0.00004 Width given is estimated corridor of impact including profile of trench, spoil piles & disturbed area in between Export 51,000 21 1 1.071 Export 5.3 (diameter) Intrafield Intrafield Intrafield 5,900 21 2 0.248 Includes 25% contingency 6 3 260 0.00468 Rock protection covering concrete mattressing: Cavendish to Murdoch and Trent to Tyne 320 10.5 2 0.00672 Option 2: Total 1.330 CF00-00-EB-108-00001 Rev C1 Page 71 of 300

1 36'E 1 48'E 2 0'E 2 12'E 54 20'N 54 20'N 54 30'N 54 30'N 54 40'N 54 40'N 0 5 10 20 Km 1 36'E 1 48'E 2 0'E 2 12'E Cygnus B NPAI Cygnus A Hub Legend Cygnus A Hub Cygnus B NPAI ETS tie-in Cygnus export pipeline Intrafield pipeline Median Line Land <20m water depth Extent of >0.5mm Extent of >2mm Cutting dispersion (mm) < 0.001 0.001-0.01 0.01-0.1 0.1-0.5 0.5-1 1-2 2-4 4-6 6-8 8-10 Environmental Statement Date Projection Spheroid Datum Data Source File Reference Checked Figure 6-2: Drill Cuttings overlay Tuesday, September 13, 2011 15:51:18 ED 1950 UTM Zone 31N International 1924 D European 1950 GEBCO, JNCC, UK Deal, RWE Dea UK 2004 J:\P951\Mxd\O_Cygnus_ES\Figure 6-2 Drill_cuttings_modelling_overlay_v1.mxd Produced By Reviewed By Emma White Rachael O'Sullivan NOTE: Not to be used for navigation 0 0.5 1 2 3 4 km Metoc Ltd, 2011. All rights reserved.

6.1.3.7 Other subsea infrastructure The ETS pipeline tie-in subsea structures comprise the wye manifold. The Wye manifold measures 24m x 12.5m covering 300m 2 of seabed. A subsea safety isolation valve (SSIV) will be also installed onto the pipeline. It is approximately 12m x 3.5m with a 42m 2 footprint. The total seabed footprint of the subsea infrastructure is thus 342m 2. 6.1.3.8 Summary of all seabed footprints Table 6-13 details the overall construction footprint on the seabed, summarising the details provided in Section 6.1.3. In reality, this estimate is expected to be extremely conservative as a number of the footprints are likely to overlap minimising the overall development footprint. Table 6-13 : Summary of all seabed footprints Activity Comment Footprint on seabed (km 2 ) Drilling Drill cuttings 0.045 Subsea infrastructure Platform installation Spud cans and rock stabilisation material (drilling rig and accommodation vessel) Installation of export and intra-field pipelines (maximum) 0.065 1.337 Subsea structures 0.000342 Cygnus A and Cygnus B platforms 0.00265 Heavy lift vessel 0.008496 Total 1.46km 2 CF00-00-EB-108-00001 Rev C1 Page 73 of 300

6.2 PRODUCTION 6.2.1 Atmosphere 6.2.1.1 Power generation Based on the equipment specifications provided in Section 5.3.3, exhaust gas emissions per annum from power generation equipment have been calculated and are presented in Table 6-14. The standard default factors as used in the UK Environmental Emissions Monitoring Scheme (EEMS) have been used and are taken from Table 8-1 and 8-2 in Root-5 Ltd (2004). Table 6-14 : Emissions from power generation Equipment Total annual running hours Expected thermal output per item (MWth) Total Emissions (tonnes) CO2 NOx N2O SO2 CO CH4 VOC Cygnus A power generation combustion engine duel fuel Cygnus A emergency power generation diesel engine Cygnus A firewater pumps (3) diesel engine Cygnus A and B cranes (4) diesel engine Cygnus A gas compression gas turbine 9,000 (8,200 gas and 800 diesel) 3.1 1,416 5.96 0.097 1.76 0.41 0.017 0.13 200 0.8 115.20 0.21 0.008 0.14 0.57 0.006 0.07 300 0.315 62.40 0.12 0.004 0.08 0.31 0.004 0.04 5,000 0.328 934.4 1.73 0.064 1.17 4.58 0.053 0.58 16,400 7 13.86 0.03 0.001 0.0001 0.015 0.004 0.0002 Total - - 2,542 8.05 0.18 3.15 5.88 0.084 0.83 6.2.1.2 Emissions from vessels Routine visits to Cygnus A and B will be carried out via helicopters and ships during the life of the development. Emissions per annum for these visits are presented in Table 6-15. Table 6-15 : Production - vessel exhaust gas emissions (per annum) Activity Vessel Types Duration (days) 1 Total Fuel Use (tonnes) Total Emissions (tonnes) CO2 CO NOx N2O CH4 VOC SOx Cygnus A & B Supply boat 64.0 640.0 2,048.0 5.1 37.8 0.1 1.7 1.5 1.3 Cygnus A Standby vessel 365 730.0 2,336.0 5.8 43.1 0.2 2.0 1.8 1.5 Transfers Helicopter 2 16.9 21.7 69.4 0.1 0.3 0.0 0.0 0.0 0.0 Pipeline inspections Dive support vessel 10.0 150.0 480.0 1.2 8.9 0.0 0.4 0.4 0.3 Total - - 1,541.7 4,933.4 12.3 90.0 0.3 4.1 3.7 3.1 Source: Emissions factors taken from Table 15 UKOOA (2002). 1 Figure given is maximum number of days vessels will be present on site per annum. 2 Assumes 1 hour (each way) helicopter flight between Cygnus A & B and North Denes, Humberside. CF00-00-EB-108-00001 Rev C1 Page 74 of 300

6.2.2 Airborne noise The potential sound sources from production are summarised in Table 6-16. The majority of the noise levels will be above sea level and so it is expected little sound above the ambient levels already generated during operation will be transmitted into the water column. The development will not significantly increase the levels of vessel activity in the region during production. Table 6-16 : Summary of production noise sources and activities Activity Source Source type Duration Power generation Transport (equipment and personnel) Turbines and generators Helicopters and supply vessels Continuous Continuous Permanent (years) Transient (days) Flaring Burners Continuous Permanent (months) Airborne noise from the Cygnus A and B platforms is expected to be relatively minor during production. Most of the machinery is concentrated on the Cygnus A processing and utilities platform. 6.2.2.1 Light emissions The Cygnus A and B platforms will be lit for safety and operational reasons during hours of darkness. Although lighting techniques are improving there is the potential that this will cause light pollution. Research is currently underway to determine the potential impact of anthropogenic light sources on bird migration patterns and the potential for causing changes in behaviour. 6.2.3 Water Resources 6.2.3.1 Produced water Well fracture process If three wells are fractured, approximately 1.77 million litres of frac proppant carrier fluid will be pumped down each well. Approximately 50% of this will be flowed-back during the frac clean-up process with the remainder being produced for the first three months of production as each well comes online. The Leman formation is a dry formation with condensate to gas ratio of 1.9bbl/mmscf. If all the free water is back-flowed within the first three months at a constant rate, the associated condensate produced during this time would be approximately 475 tonnes. All produced water discharges will be compliant with OSPAR recommendation 2005/3 i.e., oil in water concentrations <30mgl -1 and as such all free water will be processed through a separator to reduce condensate concentrations. The maximum condensate discharged from one well will be 26.55kg over a 90 day period, or approximately 0.295kg per day. If all free water was to be produced at the same time from all three wells this could increase to 0.885kg per day, or 79.65kg in total. Water from dehydrated gas The TEG dehydration unit is designed to remove water from the gas stream so that it meets the required export specifications of 6lbs/mmscf (2.7kg/mmscf). All removed water will be processed to ensure oil in water concentrations are compliant with the OSPAR recommendation 2005/3 of 30mgl -1. The maximum design capacity of the Cygnus facility is 2000bpd of produced water, however it is anticipated that normal production rate will be approximately 200bpd. It has therefore been estimated that a maximum of 9.5kg of condensate could be discharged in produced water per day with normal operations producing approximately 0.95kg per day. Included within the total hydrocarbon content are components with a relatively high solubility, which can behave differently to the insoluble oil components. These include volatile aromatic compounds (benzene, toluene, ethylbenzene and xylene (BTEX)) which are found in higher concentrations in produced water from gas fields than oil fields. However, BTEX do not persist in seawater and are not accumulated to any degree by marine organisms (OGP 2005) and are not included in the current OSPAR lists of Chemicals for Priority Action or of substances of Possible CF00-00-EB-108-00001 Rev C1 Page 75 of 300

Concern (OSPAR 2011). BTEX compounds in produced water are; however, reported through EEMS. 6.2.3.2 Produced sand (proppant) As described in Section 5.2.2.5, up to three wells will be fractured to optimise production. It is expected that each well will produce approximately 170 tonnes of proppant (graded sand) in the first three months. Temporary frac clean-up facilities will be provided on the platform until the solids rate drops below 1kg per day. At this level, the platform clean-up desanding system will take over i.e., sand will be separated from the free water in a hydrocyclone and monitored for contamination. It is proposed that the sand will be discharged to sea and an Oil Pollution, Prevention and Control (OPPC) permit will be applied for to regulate this process. All sand will be cleaned and the oil concentration tested to ensure it is within the levels permitted on the OPPC approval. As the reservoir contains a dry gas with a condensate to gas ratio of 1.9bbls/mmscf it is not expected that sand will be contaminated with reservoir hydrocarbons. However, if the required oil concentration cannot be achieved, the sand will be bagged and transported for onshore treatment and disposal. Assuming each well will produce similar quantities of sand a maximum of 510 tonnes of sand could be discharged from the three wells. It is likely that this discharge will have a similar dispersion pattern to that of the cuttings, discussed in Section 6.1.3.5. However, the particulate material will be discharged at a considerably lower rate minimising deposit thicknesses. 6.2.3.3 Waste water Supply and maintenance vessels visiting Cygnus A and B platforms during production are not likely to discharge waste water. Transit times to and from these sites are sufficiently low that all waste can be held onboard until return to port, where it can be disposed of and processed. As a worst case scenario Table 6-17 presents the possible discharges during production. Table 6-17: Total waste water discharge (m 3 ) per year during production Vessels Number of people Duration (days) Grey water (m 3 ) 1 Sewage (m 3 ) 1 Dive support vessel 70 10 105 49 Supply boat 20 64 192 89.6 Total - - 297 138.6 1 Estimates based on 150 litres of grey water per person per day and 70 litres of sewage/black water per person per day. 6.2.3.4 Chemical discharges All production chemicals will be in closed systems with no discharge to sea. 6.2.3.5 Underwater noise As stated above (Section 6.1.2.4), the majority of sound sources during production will be above sea level and therefore it is expected that little sound above the ambient threshold levels will be transmitted into the water column. Underwater noise from the platform is dominated by the noise produced by the onboard power generators at Cygnus A. The associated noise increase produced by the power generation required for the Cygnus development is expected to be minimal. Underwater noise from platforms is relatively minor because of the small surface area in contact with the water and the placement of machinery on decks well above the water. Measurements undertaken by Gales (1982 in Richardson et al. 1995) around 11 production platforms showed frequencies are low, between 4.5 and 38Hz, when measured at ranges of 9-61 m. Platforms powered by gas turbines produced higher frequencies than those with some shore power (Richardson et al. 1995). CF00-00-EB-108-00001 Rev C1 Page 76 of 300

6.2.3.6 Exclusion zones A permanent 500m radius exclusion zone will be established around the Cygnus A and B platforms and the ETS pipeline tie-in manifold. When production commences, this will mean that vessels will be excluded from approximately 2.36km 2 of sea area. 6.2.4 Seabed Conditions No additional seabed disturbance is anticipated during production activities CF00-00-EB-108-00001 Rev C1 Page 77 of 300

7.0 ACCIDENTAL EVENTS Accidental events are incidents or non-routine events that have the potential to trigger impacts that would otherwise not be anticipated during the normal course of construction, operation or decommissioning. The severity of impact from the accidental events of concern can be greater than the severity of potential impacts associated with routine operations, however the probability of an accidental event occurring is typically much lower. Given the high potential severity of accidental events, they require plans specifically designed to respond to the event as quickly and effectively as possible. In addition to mobilising the operator s resources, additional resources from external parties such as government agencies are often an inherent part of the incident response. GDF SUEZ E&P UK will submit an oil pollution emergency plan (OPEP) to the DECC Offshore Inspectorate for approval to cover drilling and production at Cygnus. The OPEP will comply with the requirements of The Offshore Installations (Emergency Pollution Control) Regulations 2002 and The Merchant Shipping (Oil Pollution Preparedness, Response Co-operation Convention) Regulations 1998 and take into consideration recent revised guidance from the DECC following the Gulf of Mexico Macondo incident. For the purpose of this assessment, the following accidental events have been considered: Hydrocarbon spills and leaks Chemical spills and leaks Dropped objects The accidental release of hydrocarbons from the identified potential worst case scenarios has been assessed and modelling carried out to characterise the extent of the impact. These results are presented in Appendix D. 7.1 TYPES OF ACCIDENTAL EVENT 7.1.1 Hydrocarbon spills and leaks The liquid hydrocarbons produced and utilised during the project phases at Cygnus include produced gas and condensate, diesel, lubricating and hydraulic oils and aviation fuel. The characteristics of these potential hydrocarbon spills/releases are summarised below. Produced gas There is a possibility that a gas release could occur during construction drilling or production. Gas is non toxic and disperses rapidly therefore would have a minimal impact on the marine environment. Condensate Although condensates may have some toxic components they are biodegradable and generally behave in a similar manner to diesel (see below). As such they vaporise and disperse rapidly having a minimal impact on the marine environment. Diesel Marine diesel used in mobile drilling rigs and support vessels is a low viscosity distillate fuel. Diesel contains a high proportion of lighter hydrocarbons, such that evaporation is an important process contributing to the removal of spilt diesel from the sea surface. Evaporation will be enhanced by higher wind speeds and warmer sea and air temperatures. The general behaviour of diesel at sea can be summarised as follows: A slick of diesel will elongate rapidly in the direction of the prevailing wind and waves. Very rapid spreading of the low viscosity diesel will take place. Some diesel fuel oils may form an unstable emulsion at the thicker, leading edges of the slick. Speed of physical dispersion of the surface slick increases with wind speed. Up to 95 % of a slick may disperse within about 4 hours of the spill in 15 knot winds and sea conditions. CF00-00-EB-108-00001 Rev C1 Page 78 of 300

Lubricating and Hydraulic Oil Lubricating oils behave in a manner similar to marine diesel but are more viscous, slowing down the spread of the slick marginally. As lubricating oils are considerably refined, they do not contain the same quantity or ratio of light-end hydrocarbons. Hydraulic oils are medium oils of light to moderate viscosity. They have a rapid spreading rate and generally dissipate quickly, particularly in higher sea states. Lubricating and hydraulic oils are used in a variety of equipment on both drilling rigs and support vessels and are stored in containers ranging from 20 to 1,000 litres. Aviation Fuel Aviation fuel is volatile and evaporates and spreads quickly. Since the fuel will mostly evaporate, leaving little or no visible mass left on the surface within 24 hours, it is unlikely there would be sufficient time for clean-up operations in the event of a spill. Aviation fuel is used for refuelling helicopters that transport equipment and personnel to shore from the drilling rig, the Cygnus platforms and other offshore vessels. 7.1.2 Chemical spills and leaks During the life of the project there is the potential for chemical spills and leaks to occur. Spills may result in localised impacts on water quality and toxicity effects on marine fauna and flora. Chemical spills include accidental leakage of hydraulic fluid or chemical inhibitors used in the wells or accidental release of chemicals during transfer between vessels. A comprehensive list of chemicals will be developed during the detailed engineering phase of the project and submitted in an application to the DECC under the Offshore Chemicals (Amendment) Regulations 2011 as appropriate. Bulk chemicals stored during the commissioning and operational phase of the project are likely to include: Hydrate inhibitors Corrosion inhibitor Halite scale inhibitors Wax inhibitors Foaming and anti-foaming agents Oil based drilling mud Water based drilling mud The impact of a spill of any of these chemicals will depend on the chemical type, volume released and individual receptors. The volume of chemicals present during construction and production will be managed to minimise the potential for spillage to the sea. In addition measures such as the use of a hazardous drainage system, bunding and containment, preventative maintenance and inspection, will reduce the likelihood of spills. 7.1.3 Dropped objects Dropped objects have the potential to increase the project footprint on the seabed if the objects are not recovered. They also pose a risk to other sea users as snagging hazards, collision risks or they can become caught in propellers. Occurrences of dropped objects are most likely during construction activities and during vessel transfer operations. Dropped objects will be removed where possible and a debris clearance survey will be undertaken at the end of the construction phase. If it is not possible to remove them, dropped objects will be reported to the DECC in a PON2 to notify other sea users of their presence. 7.2 PROBABILITY OF ACCIDENTAL EVENTS OCCURRING Typically, the likelihood of accidental events occurring is minimised through legislation governing the industry, emergency shut-down procedures and multiple control and mitigation measures consistent with industry best practice across the project cycle. Events are possible during both the construction and production phase. The most frequently expected type of accident would be a small (<1 tonne) spill of oil or chemical from the rig or platform during bulk transfer to/from the facilities, leakage or during operational use or storage. CF00-00-EB-108-00001 Rev C1 Page 79 of 300

Occurrences of major spills (>100 tonnes) are rare. The probability of such events occurring on this project, during construction and production, has been assessed below. UK legislation requires Operators to identify the worst case hydrocarbon spill scenarios that could occur during construction and production operations. Two construction scenarios and one production scenario have been identified for the Cygnus field development: a) Loss of well containment e.g. well blow out 670m 3 (at a rate of 2.8m 3 /hr for ten days) b) Total loss of containment of the diesel inventory on the drilling rig as a result of a collision 750m 3 (578 tonnes) of diesel c) Loss of containment in the export pipeline 0.152m 3 of condensate The probability of such an event occurring on this project, during construction and production, has been assessed below. 7.2.1 Construction Historical spill data in the UK is collated by both the DECC and the Maritime and Coastguard Agency (MCA). The DECC collates incident reports from offshore oil and gas installations, including drilling rigs, whereas the MCA collates incident reports from UK vessels, including those associated with support & construction activities for the oil and gas industry. The MCA data also incorporates data reported to the DECC to provide an overview of all marine incidents. Both sets of data have been used in the analysis below during the 39 month Cygnus construction period, during which the following vessel activity is envisaged: Drilling rig 39 months Standby vessel 39 months Anchor handling vessel 24 days Supply vessel 393 days Trencher 60 days DSV / MSV (multi service vessel) 80 days Survey vessel 75 days Guard vessel 145 days S-lay vessel 40 days Reel-lay vessel or J-lay vessel 20 days Heavy lift vessel 20 days Temporary accommodation vessel 20 days Anchor lay vessel 90 days Four tugs 40 days Helicopter (crew transfers) 8 trips The spill risk associated with these activities can be divided into two main categories: a) Offshore support vessels (e.g., standby, construction and supply vessels) b) Drilling rig Available data from the MCA (ACOPS 2011) has been reviewed for years 2000 to 2009 to establish the probability of a spill occurring from an offshore support vessel (category a above). However, there are only two reported incidents which suggests, there is either little reported data for construction related incidents or the percentage of incidents is very low. Given the lack of data, an estimation of the likelihood of a spill from a support vessel occurring per annum would not be statistically valid. Historic data held by the DECC are more descriptive and can be used to establish the probability of a diesel spill during drilling operations (category b above). Records for spills from mobile drilling CF00-00-EB-108-00001 Rev C1 Page 80 of 300

units have been analysed for the period 2003 to 2007. Excluding very small spills (<0.1 tonnes), data for this period shows there were 32 spills from drilling rigs. Of these, 26 were less than 1 tonne and one was over 10 tonnes (13.4 tonnes oil based mud in 2006). Over the same period it is estimated that there were approximately 1,100 wells drilled from mobile drilling units such that the probability of a release of greater than 0.1 tonnes is approximately 3% per well. At Cygnus there will be up to ten wells drilled which gives a 30% likelihood of a spill greater than 0.1 tonnes. There is not enough data for the larger spills (>10 tonnes) to estimate the likelihood of such a spill statistically although it can be inferred from the data that such spills are very rare. 7.2.2 Production As discussed above the worst case spill event during production would be a total loss of containment of the export pipeline resulting in a gas release with possibly small amounts of associated condensate and MEG. The report Riser & Pipeline Release Frequencies by the OGP (OGP 2010) states that failures in the pipeline may occur as a result of: Loads exceeding pipeline critical loads, usually resulting in an isolated incident Gradual weakening of the pipeline over a period of time. The primary causes of pipeline failures are critical loads that may lead to an isolated incident e.g., loads from trawl boards, ship anchors or subsea landslide. The second cause of pipeline failures are mechanisms which act over time, which include corrosion, open spans causing fatigue and buckling (OGP 2010). The OGP provides the suggested pipeline failure frequencies for the UK offshore oil and gas industry based on the above potential causes (see Table 5-5). For a subsea pipeline in open sea, there are two categories of pipeline: 1) a pipeline containing unprocessed fluid; 2) a processed oil or gas, pipeline diameter 24 inch. The intra-field pipeline, which falls into the first category, is 5.9km long and it can be inferred that the failure frequency for this pipeline is 0.0032 failures per year. The export pipeline which falls into the second category is 51km long and it can be inferred that the failure frequency for this pipeline is 0.00252 failures per year. The combined pipeline failure frequency for the full development is therefore 0.0057 failures per year and over the field life of 35 years is 18% (OGP 2010). Table 7-1 : Industry riser and pipelines failure frequencies Pipeline Category Failure frequency Unit Subsea pipeline: in open sea Subsea pipeline: external loads causing damage in safety zone Flexible pipelines: subsea Risers Source: OGP (2010) Well stream pipeline and other small pipelines containing unprocessed fluid Processed oil or gas, pipeline diameter 24 inch 5.0 x 10-4 Per km/year 5.1 x 10-5 Per km/year Diameter 16 inch 7.9 x 10-4 Per year All 2.3 x 10-3 Per km/year Steel diameter 16 inch 9.1 x 10-4 Per year Flexible 6.0 x 10-3 Per year CF00-00-EB-108-00001 Rev C1 Page 81 of 300

7.3 OIL SPILL MODELLING 7.3.1 Construction During the construction phase, two spill scenarios have been considered which, represent the worst case spill scenarios for a condensate and diesel spill: Loss of well containment e.g. well blow out 670m 3 (at a rate of 2.79m 3 /hr for ten days) Loss of rig inventory 750m 3 (577.5 tonnes) of marine diesel Modelling was commissioned for both scenarios and the results are presented below and in greater detail in Appendix D. It should be noted that all modelling information provided is generic and illustrative only and not intended to be relied upon in any specific instance. This is because in practice any number of variables may impact on an oil spill or other environmental incident and as such should be addressed on an individual basis, taking account of the specific conditions encountered. Loss of well containment The loss of well containment scenario was modelled using two types of models: Stochastic - This type of modelling is carried out for the most persistent type of hydrocarbon within the project scope. A stochastic model, also known as a probability model shows the probability distribution for potential impacts of a hydrocarbon spill, over a defined time. The model uses historical wind data to run a series of trajectories for all wind directions i.e., the 12 points of the compass, and then calculates the probability of a spill following any particular trajectory. The contours indicate the probability of the spill spreading to the extent shown for a particular wind direction. The results for each of the 12 wind directions are overlain in to one final diagram which indicates the probability of oil being found at a distance from the spill rather than the total extent of a single spill. This type of modelling is an important tool for determining the areas of coastline that could potentially be affected by a spill and therefore the best locations to place oil spill response equipment. However, this type of diagram is typically the most misunderstood part of an Environmental Statement or Oil Pollution Emergency Plan. The most important thing to note is that it does not illustrate the extent of the area which will be affected if a spill occurs. Trajectory - A trajectory or deterministic model is used to predict the route of a hydrocarbon slick over time and under defined weather and current conditions. UK legislation requires that two trajectory models are undertaken for each spill scenario investigated by the oil and gas industry; one trajectory using a 30 knot wind blowing towards the nearest stretch of UK coastline; and one trajectory using a 30 knot wind blowing towards the closest international boundary. Although the estimated time to mobilise and drill a relief well is 90 days, modelling using the OSIS software is not possible for this duration. Instead, the models were run for a period of ten days, which for planning purposes is believed to be sufficient. It is likely that if beaching is going to occur, it will do so within this period for most scenarios based in the UKCS (depending upon the oil type, meteorological conditions and location of the spill release point). Well blow out Condensate is a light hydrocarbon and modelling over 10 days shows that any condensate released in this period will fully disperse and evaporate within this time period. Therefore, any condensate released after 10 days will not increase the extent of the area impacted by a spill. Modelling undertaken for this period of time also acts as a good indicator of beached volumes as after 10 days additional response procedures (i.e., shoreline recovery and use of dispersants) should be in place to reduce the amount of oil that will beach. Figure 7-1 shows the output of the stochastic model for the continuous release of condensate at a rate of 2.8m 3 /hr for ten days. The model output illustrates the extent of the condensate spill after ten days, based on the probability of winds blowing from each of 12 directions and provides the probability of the spill reaching a particular area. In this scenario there is a 0% chance of the condensate beaching or reaching the UK/Netherlands boundary under any of the 12 wind directions. CF00-00-EB-108-00001 Rev C1 Page 82 of 300

Figure 7-1 : Stochastic model of worst case condensate well blowout 2.79m 3 /hr hours (670m 3 ) released over 10 days a) Overview b) Detailed view Note: Plot represents the combination of spill scenarios from 12 different wind directions. Probability legend Wind data Source: OCR (2011) Trajectory modelling was undertaken for 670m 3 of condensate released at a rate of 2.79m 3 /hr over ten days. The results of the trajectory modelling applying extreme (constant 30 knot) wind conditions towards the UK coastline (Figure 7-2) indicates the distance to the leading edge of the spill will be 1.2km from the discharge point, which is 160km from the closest point on the UK coastline in the Saltwick Bay area. The trajectory model applying a 30 knot wind towards the nearest international boundary (Figure 7-3) indicates that the distance to the leading edge of the spill will be 1.4km from the discharge point, which is 37.2km from the UK/Netherlands boundary. CF00-00-EB-108-00001 Rev C1 Page 83 of 300

Figure 7-2 : Trajectory model - 670m 3 continuous condensate spill over 10 days with 30 knot wind towards UK coastline a) Overview b) Detailed view c) Fate of spill volume Source OSR (2011) CF00-00-EB-108-00001 Rev C1 Page 84 of 300

Figure 7-3 : Trajectory model - 670m 3 continuous condensate spill over 10 days with 30 knot wind towards closest international boundary a) Overview b) Detailed view c) Fate of spill volume Source OSR (2011) CF00-00-EB-108-00001 Rev C1 Page 85 of 300

Loss of rig inventory The worst case scenario for a diesel spill would be a complete loss of containment of the drilling rig (e.g., following a collision). Marine diesel is a heavier fuel than standard automotive diesel and will therefore persist for a longer time in the environment when spilt. However, as a Group 2 oil, marine diesel has a high proportion of volatile light ends, which evaporate quickly on release. As such, it is non-persistent and will evaporate and dissipate quickly, rarely needing cleaning up. Typically 90% of a diesel spill evaporates or disperses naturally within the water column within 1 to 2 days (ITOPF 2007). In addition, the low asphaltene content of diesel will prevent the formation of any stable emulsions, which could otherwise lead to a significant increase in slick volume. Figure 7-4 presents the stochastic model output of a complete and instantaneous loss of containment of the drilling rig (750m 3 ). The model output illustrates the extent of the diesel spill, based on the probability of winds blowing from each of 12 directions and provides the probability of the spill reaching a particular area. In this scenario there is a 0% chance of the diesel beaching or reaching the UK/Netherlands boundary under any of the 12 wind directions. Figure 7-4: Stochastic model of worst case diesel spill of 750m 3 instantaneous release from drilling rig Note: Plot represents the combination of spill scenarios from 12 different wind directions Probability legend Wind data Source: OCR (2011) Trajectory modelling was undertaken for a 750m 3 diesel spill from the rig of under extreme (constant 30 knot) wind conditions towards the UK coastline (Figure 7-5) and towards the nearest international boundary (Figure 7-6). It is estimated that the distance from the leading edge of the spill from the source will be 16.6km which is 145.5km from the UK coastline in a 30 knot wind blowing towards the coastline. In a 30 knot wind towards the UK/Netherlands boundary the leading edge of the spill will reach 20.5km from the source and will be 18km from the boundary. In both cases the modelling (Figure 7-5 and 7-7) indicates that the diesel spill disperses and evaporates within eight hours. It is estimated that 304m 3 will evaporate and approximately 446m 3 will disperse. CF00-00-EB-108-00001 Rev C1 Page 86 of 300

Figure 7-5 : Trajectory model - 750m 3 instantaneous diesel spill with 30 knot wind towards UK coastline a) Overview b) Detailed view c) Fate of spill volume CF00-00-EB-108-00001 Rev C1 Page 87 of 300

Figure 7-6 : Trajectory model - 750m 3 diesel spill with 30 knot wind towards closest international boundary a) Overview b) Detailed view c) Fate of spill volume Source OSR (2011) CF00-00-EB-108-00001 Rev C1 Page 88 of 300

7.3.2 Production During production the worst case hydrocarbon spill scenario would be a pipeline breach resulting in full loss of containment of the export pipeline. If this were to happen, a maximum of 14,146m 3 of gas and approximately 0.151m 3 of condensate (one pipeline volume) could be released before containment measures activate. As discussed in Section 7.1.1, gas is non toxic and disperses rapidly and therefore would have a minimal impact on the environment. The volume of condensate released is extremely small relative to the potential volumes that could be spilt during construction activities. Modelling of the potential condensate release has not been undertaken as it is expected to evaporate and disperses within an hour. CF00-00-EB-108-00001 Rev C1 Page 89 of 300

8.0 IMPACTS ON PHYSICAL ENVIRONMENT 8.1 AIR In order to understand potential impacts from a development on the environment, it is fundamental to have a clear understanding of the present state of the environmental baseline. For the purposes of this report the environment has been split into three categories: physical, biological and human. This section covers the physical environment and has been organised as follows: Describe data sources used Present baseline conditions for the physical environment Potential impacts from the Cygnus development on the physical environment Proposed mitigation measures to curtail, limit or eliminate potential impacts Significance of the residual impacts if mitigation measures are implemented The physical environment has been divided into the following main areas: Air (Section 8.1) Climate change (Section 8.2) Water resources (Section 8.3) Seabed conditions (Section 8.4) 8.1.1 Baseline Data Sources The main sources of data for this section are: UK National Air Quality archive: Defra (2011) Cygnus Phase 1 Development Metocean Design Basis: Metoc plc (2009) Metocean criteria for UKCS Blocks 44/11 and 44/12: Fugro Geos (2008) Cygnus Exploration Well Environmental Statement: GDF Britain (2005) 8.1.2 Existing Baseline 8.1.2.1 Air quality An understanding of the existing air quality in the area of the development is useful when assessing the potential future impact upon air quality from the proposed operations. In general, UK air quality has been improving since 1990. Emissions of NOx (oxides of nitrogen) and SO2 (sulphur dioxide) have decreased by 46% and 82% respectively due to reduced emissions from road transport and power stations (Dore et al. 2008). Data on offshore air quality is limited due to absence of an offshore air quality monitoring station network. However, the gases are generally of limited concern in the offshore sector given the distances to sensitive receptors i.e., communities on land or fixed installations. Levels of primary pollutants, which are emitted directly i nto the atmosphere, tend to be highest around their sources i.e., in urban and industrial areas. The nearest air quality monitoring station to the Cygnus development is at Middlesbrough, 220km west of the development, positioned in an urban location. It can therefore be assumed that in areas as distant as 220km offshore where there are considerably less point sources of primary pollutants, air quality is likely to be significantly better than within the urban environment of Middlesbrough. CF00-00-EB-108-00001 Rev C1 Page 90 of 300

Table 8-1 : Summary of 2010 annual emissions to air at Middlesbrough monitoring station Pollutant Units Annual Maximum Annual Mean UK Air Quality Objective CO mgm -3 3.2 0.2 10 (running 8 hour mean) NOx µgm -3 497 30 Objective only applicable for protection of vegetation & ecosystems NO2 µgm -3 117 22 40 (annual mean). 200 (1-hour mean) SO2 µgm -3 80 4 350 (1-hour mean). 125 (24 hour mean) 8.1.2.2 Wind regime The wind regime over the open waters of the SNS is highly variable, both in direction and strength, due to the numerous mobile depressions which cross the area. Prevailing winds in the project area are generally south-westerly / westerly but deviate to no rtherly during late spring. An annual wind rose for the development is presented in Figure 8-1. Representative seasonal wind roses are presented in Appendix 5. The most frequent wind speeds are between 2.6 and 12.5ms -1 (Beaufort Force 2-6, light to strong breeze) (Metoc plc 2009). As is to be expected, the strongest winds occur during the winter months (December to February), whereas summer months (May to August) are calmer. 8.1.3 Potential Impact Identification This EIA has identified that during the project life cycle the activities listed in Table 8-2 have the potential to emit pollutants to air. Table 8-2 : Air quality - potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movement of transportation Exhaust gas emissions Localised deterioration in air quality Drilling of wells Flaring of gas Localised deterioration in air quality Production Physical presence and movement of transportation Power generation Gas venting Flaring Exhaust gas emissions Release of gas Release of combustion gases Localised deterioration in air quality All these aspects have a potential to deteriorate site specific (i.e., within the project area) air quality for a short-term period of time, although the change to the baseline will be of low magnitude. The likelihood, spatial extent, magnitude and duration of the individual activities potential impacts have been assessed in Section A of Appendices 2.2 2.3. CF00-00-EB-108-00001 Rev C1 Page 91 of 300

Figure 8-1 : Annual wind rose for the Cygnus development CF00-00-EB-108-00001 Rev C1 Page 92 of 300

8.1.4 Mitigation Measures GDF SUEZ E&P UK and any contractors will undertake practical steps to minimise atmospheric emissions. These include, but are not limited to: Use of low sulphur content fuels where possible. Ensuring efficient operations by keeping all power generation equipment well maintained. Selecting combustion equipment in line with the requirements of indicative BAT, to minimise emissions and energy consumption. Engineering studies are ongoing to determine the most appropriate operationally and economically feasible option. Flaring and venting will be within permitted levels as outlined in the relevant permits and will be kept to the minimum required for safe operations. Checking whether contractors have ISO 14001. 8.1.5 Residual Impact Significance Assessment Emissions of carbon dioxide (CO2), carbon monoxide (CO), oxides of nitrogen (NOx), and oxides of sulphur (SOx) will result from power generation from the drilling rig and platforms, transportation associated with the development, flaring and venting. During construction, approximately 1,305 tonnes of NOx and 44.33 tonnes of SOx will be emitted to the atmosphere from vessels and flaring (Section 6.1.1.1 and 6.1.1.2). During production, approximately 98 tonnes of NOx and 6.3 tonnes of SO2 will be emitted per annum (Section 6.2.1). Emissions of CO, SOx and NOx are known contributors to degradation of regional and local air quality. The European Commission has set threshold/limit values for NOx, SOx and CO concentrations in ambient air to improve the protection of human health and the environment. The air quality objective for SO2 is 125µgm -3 as a 24 hour average. For NO2 the hourly mean air quality objective is 200µgm -3 and the annual mean is 40µgm -3 and for CO it is a maximum running 8 hour daily mean of 10mgm -3 (Defra 2007). However, the gases are generally of limited concern in the offshore sector given the distances to sensitive receptors, i.e., communities on land or fixed installation. The Cygnus development is 160km from land and 15km from the nearest manned installation (Murdoch platform complex). Dispersion modelling undertaken for activities associated with the Cygnus exploration well ES (well testing and exhaust emissions, GDF Britain 2005) demonstrated concentrations of NOx and SOx were diluted to <1µgm -3 within 500m of the discharge point, well below health and environmental guidelines. The model assumed that activities burned 15 tonnes of fuel per day. Construction vessels and the drilling rig for the Cygnus development are estimated to consume around 10-15 tonnes per day, except the anchor handling vessel which will consume 25 tonnes per day but will only be present for 24 days (see Table 6-1). All daily use figures are below or comparable to the figures modelled and it can be assumed that concentrations of NOx and SOx will be diluted to similar concentrations in the generally windy offshore environment. Although CO was not modelled it is considered that it will similarly be diluted. In 2009, 1.5 million tonnes of oil and gas were flared from installations with 55,763 tonnes of that from 30 mobile drilling rigs undertaking well testing (OGUK 2009). This is equivalent to the emission of 169,425 tonnes of CO2, 150 tonnes of NOx and 0.72 tonnes of SO2 released during well testing. In comparison, assuming four wells are drilled in one year including one that would involve an extended well test, the well tests at Cygnus would represent 15.3% of CO2 emissions. Emissions from power generation during production are generally comparable with other manned installations in the SNS. For example, the Murdoch platform complex emitted 688 tonnes of NO x (compared to an estimated 98 tonnes per annum for Cygnus (Table 6-14)) in 2009 (OGUK 2009). Given the generally dynamic environment offshore, concentrations of NOx and SOx are not expected to reach European Commission alert thresholds and no residual impacts on regional air quality are expected. 8.2 CLIMATE CHANGE 8.2.1 Baseline Data Sources Information for this section was drawn from UK Policy Planning Statement 25: Development and Flood Risk (CLG 2010). To help organisations to assess their vulnerability to climate change and CF00-00-EB-108-00001 Rev C1 Page 93 of 300

plan appropriate adaptation strategies the UK Government established the UK Climate Impacts Programme (UKCIP). The programme established scenarios for future climate change in the UK, taking in to consideration current and future mitigation measures to be implemented by UK Government. These scenarios have been used to predict what the future environmental baseline at the Cygnus development will be as the environment responds to climate change. 8.2.2 Existing Baseline There is an increasing body of evidence showing that global climate is changing as a consequence of human actions. Past, present and future emissions of greenhouse gases are expected to cause significant global climate change during the next century. Sea level will continue to rise, having implications for wave heights, wave propagation, storm events, flooding and coastal erosion. Sea temperatures, salinity and nutrient levels may also rise with implications for biological processes. The magnitude of sea level rise is dependent on greenhouse gas emissions, the sensitivity of the climate system and the relative local vertical movement of the surrounding land masses. The UK land mass is generally falling in the south-east and rising in the north and west. The UK Government has recommended that a net sea level rise of 2.5 mm/yr up to 2025 and 7 mm/yr from 2025 to 2055 should be allowed for in areas north of Flamborough Head (CLG 2010). This would equate to an increase in water depth across the Cygnus project area of 3.5 cm by 2025 and 10.5 cm by end of field life in 2040. It is predicted that a rise in sea level will change wave heights due to increased water depths, and may change the frequency, duration and severity of storm events. The Government suggests that a 5% sensitivity allowance should be added to offshore wind speeds and wave heights by 2055 and 10% by 2155 (CLG 2010). Sea temperatures in the SNS may rise by between 1.5 and 4.0 C by 2098 (UKCIP 2009). The UKCIP predict that seasonal precipitation will change on the North East coast decreasing by between 0 and 10% by 2020 and increasing by 30 and 70% by 2080 during winter months (UKCIP 2009). The increase in runoff from the east coast catchment areas is predicted to cause changes in offshore salinity and nutrient status (JNCC 2008). 8.2.3 Potential Impact Identification The EIA identified that during the project life cycle the activities presented in Table 8-3 have the potential to interact with climate change. Table 8-3: Climate change - potential impact identification Construction Project Activity Aspect Potential Impact Physical presence and movement of transportation Drilling of wells Production Physical presence and movement of transportation Power generation Gas venting Flaring Exhaust gas emissions Flaring of gas Exhaust gas emissions Exhaust gas emissions Release of gas Release of combustion gases Loading of greenhouse gases e.g., CO2, methane (CH4) Loading of greenhouse gases e.g., CO2, CH4 These aspects all have the same potential impact in that they could lead to loading of greenhouse gases, increasing the rate or magnitude of climate change. The EIA concluded that the potential impact would affect the wider environment, but would be of low magnitude with a short duration. The assessment is provided in Section B of Appendices 2.2-2.4. 8.2.4 Mitigation Measures The key atmospheric emissions that contribute to climate change are CH4 (methane) and CO2. Measures to reduce atmospheric emissions were discussed under the air quality section. The CF00-00-EB-108-00001 Rev C1 Page 94 of 300

same measures will be instrumental in addressing emissions of CH4 and CO2. In addition, the following with be undertaken: Flaring and venting will be within permitted levels as outlined in the relevant permits and will be kept to the minimum required for safe operations. Emissions from power generation will be managed under the relevant permits for the development. Inspection and maintenance programmes will be used in line with the requirements of indicative BAT to ensure that combustion equipment is kept and operated in a manner to optimise efficiency and minimise fuel consumption where appropriate. Checking whether contractors have ISO 14001. 8.2.5 Residual Impact Significance Assessment Approximately 69,218 tonnes of CO2 will be emitted during construction in the form of exhaust emissions and around 7,475 tonnes per annum during production. Well testing will produce up to 73,551 tonnes of CO2. It is generally acknowledged that CO2 emissions contribute to global warming and climate change and are therefore considered a global issue. To assess the potential impact of the project emissions on climate change they have been considered in the context of the UK s global contribution. Records of offshore CO2 emissions were obtained for UK oil and gas installations (fixed and mobile) and national shipping for 2009 (OGUK 2009, NAEI 2011). Data from subsequent years are not yet in the public domain. For comparison purposes, data has been split between emissions from the drilling rig, emissions from construction vessels and emissions during production. Figures calculated for the proposed Cygnus development have been adjusted pro-rata to allow comparison against annual figures. Table 8-4 indicates that construction emissions would represent 1.08% of the annual offshore emissions from similar activities. Emissions during production would account for 0.005% of the UK emissions from offshore installations. Both figures are relatively small contributions to annual UK emissions and as explained below are typical for a standard gas development of this size. Table 8-4 : Comparison of UK and Cygnus CO2 emissions - Annual Development Stage Activity Cygnus CO2 Emissions (tonnes) 1 UK Offshore O&G Emissions 2009 (tonnes) Comparison: Percentage of UK Construction Construction vessels Drilling rig Diesel consumption Diesel consumption 22,818 4 4,675,000 2 0.5% 8,176 5 423,232 3 1.9% Well testing - 25,843 6 169,425 15.3% Total - 56,837 5,267,657 1.08% Production Installation - fixed Support vessels Diesel and fuel gas consumption Diesel consumption 7,475 7 149,930,171 0.005% 4,933 4,675,000 2 0.1% Notes: 1 See Table 6-1 and Table 6-2; 2 Thomas & Thistlewaite (2008); 3 OGUK (2009); 4Based on pipeline construction for four months and drilling activities for 365 days 5Based on the drilling rig present for 365 days; 6 Assuming four wells drilled in one year, including one extended well test. 7 See Table 6-14 Based on the above discussion, the EIA has concluded that the project will not be a significant contributor to global warming and there will be no residual impact. CF00-00-EB-108-00001 Rev C1 Page 95 of 300

8.3 WATER RESOURCES 8.3.1 Baseline Data Sources This section principally references the following secondary data sources: Strategic Environmental Assessment technical reports including information on water quality (DTI 2001a,b; DECC 2009b,d; DECC 2011b) Quality Status Report (OSPAR Commission 2010) The Southern North Sea Marine Natural Area (Jones et al. 2004) Cygnus Phase 1 Development Metocean Design Basis (Metoc plc 2009) Metocean criteria for UKCS Blocks 44/11 and 44/12 (Fugro Geos 2008) 8.3.2 Existing Baseline 8.3.2.1 Water quality Although the water column over the Dogger Bank remains relatively well mixed, even during the summer months, there are many sources of contamination entering the North Sea which can affect water quality. For example, riverine inputs, coastal run-off and offshore activities. Pollutants of the water column can be split into the following distinct areas: Organics (including hydrocarbons) Trace metals Radionuclides An offshore Strategic Environmental Assessment (SEA) undertaken by the DTI in 2001 included a review of chemical contamination conducted by CEFAS and the Fisheries Research Service (FRS) to identify background levels and trends in the North Sea. This was updated as required in the 2 nd Offshore Energy SEA (OESEA2) issued in 2011 (DECC 2011b). The review indicates that inshore estuaries and coastal sites subject to high industrial usage, show the highest levels of chemical contamination (Table 8-5; DECC 2011b). Open seas continue to be little affected by pollution as riverine inputs and atmospheric deposition reduce (DECC 2009b). Offshore waters generally contain lower concentrations of polyaromatic hydrocarbons (PAH) and total hydrocarbons (THC) than riverine environments. For example, PAH concentrations exceeding 1µgl -1 were found in four UK eastern coast estuaries compared to concentrations between 0.018-0.09µgl -1 offshore in the German Bight (DTI 2001b). Similarly, Law et al. (1994, in DTI 2001b) found that THC concentrations offshore are generally very low (2.5µgl -1 ) compared to levels found in some estuaries (64µgl -1 ) (DTI 2001b). High concentrations of THCs, in the range of 30-43µgl -1, are found in the immediate vicinity of some offshore oil and gas installations, although concentrations generally fall to background levels within a short distance from the discharge point (DTI 2001b). The OESEA2 identifies that of the nearly 250,000 tonnes of chemicals discharged from oil and gas installations in 2007, 87% were considered to pose little or no risk to the marine environment (PLONOR). CF00-00-EB-108-00001 Rev C1 Page 96 of 300

Table 8-5 : Summary of contaminant levels typically found in surface waters of the North Sea Location THC PAH PCB Ni Cu Zn Cd Hg (µgl -1 ) (µgl -1 ) (ngl -1 ) (µgl -1 ) (µgl -1 ) (µgl -1 ) (ngl -1 ) (ngl -1 ) Oil & Gas Installations Estuaries 12-152 1-30 - - - - - - - Coast 2 0.02-0.1 Offshore 0.5-0.7 >1 302 - - - - - Below detection 1-104 0.2-0.92-0.2-0.6 0.3-0.7 0.3-0.6 0.5-2.2 0.5-1.4 Source: Law & Hudson (1986), OSPAR Commission (2000), Law et al. (1994), SOAEFD (1996) 10-32 0.25-41 10-51 1.6-69 Historically there have been two main sources of contaminants from oil and gas activity in the North Sea: produced water and drill cuttings. With the introduction of OSPAR decision 2000/3, hydrocarbon input from drill cuttings has been essentially eliminated, as OBM is no longer discharged to sea. However, there is a legacy of contamination which remains, in the form of historic cuttings piles around some installations, which can release hydrocarbons if disturbed by work or trawling (OSPAR Commission 2010). Produced water is now the main contamination source, containing both hydrocarbons and chemicals. Discharges from SNS installations are relatively small and monitored contaminant concentrations are continuing to fall (DECC 2011c). The major group of chemicals used in the SNS are those involved in gas treatment (for hydrate suppression or dehydration). Discharges of the other chemical function groups in the Southern Gas fields are minimal and the range of products required for gas production is considerably smaller than that required for oil production. In terms of trace metal contamination, data suggests that concentrations of nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd) and lead (Pb) are higher in the SNS than in the NNS with the exception of Pb. This is largely attributed to the close proximity to industrialised areas on land leading to higher levels of atmospheric deposition (DECC 2009d). The lower levels of Pb in the SNS are the result of the quick removal of dissolved Pb onto the surfaces of suspended particulate matter, which is relatively high in this sea area (DTI 2001b). Data presented in OESEA (DECC 2009d) indicate that concentrations of metals in the North Sea are highly variable but appear to be decreasing. Inputs of natural radionuclides to the SNS are mainly from phosphate fertiliser production but the offshore oil and gas industry also contributes (OSPAR Commission 2010). Artificial radionuclides typically originate from the nuclear facilities at Sellafield and Hartlepool (UK) and Cap de la Hague (France) (Jones et al. 2004). Concentrations of naturally occurring radionuclides within produced water are very low, but the volume of water produced is large and increasing, as fields become older. As the radionuclides discharged are naturally occurring, it is difficult to identify elevated concentrations originating from specific activities and OSPAR identify that further work is required to assess the significance of the oil and gas industry s influence (OSPAR Commission 2010). There is limited water quality data specific to the Dogger Bank and the Cygnus project area. However, Rowlatt and Davies (1995, in DTI 2001b), pointed out that there are pronounced levels of PAHs in the open sea, especially in the area around 55.5 N and 0 E, near the Dogger Bank. Additionally, relatively high, dissolved Pb concentrations in the vicinity of the Dogger Bank have been found. This may be attributed to the comparatively clear waters of this area, where there are little suspended particulates to remove dissolved Pb from the water column (DTI 2001b). 8.3.2.2 Tides and currents The North Sea has a predominantly tidal current regime, supplemented periodically by storm surge currents. There is also a weak background circulation which contributes a small eastward drift at the project area. The tides are semi-diurnal with tidal streams running east-south-east and westnorth-west. Generally in the SNS, storm surge currents tend to move in a southerly direction parallel to the English Coast and can exceed the speeds associated with tides. Currents are highly affected by the presence of the Dogger Bank, which alters the properties of the tidal currents moving over and around it. Tidal current velocities tend to be stronger to the west CF00-00-EB-108-00001 Rev C1 Page 97 of 300

and southwest of the Bank and reduced over the shallower top, owing to the partial reflection of the tidal wave and frictional dissipation. Eddies are also likely to be formed, adding to the reduction of current velocity and increasing sedimentation over the bank (Kroncke and Knust 1995). Wave motion is the most erosive force acting on seabed sediments (see section on waves below) as past research has shown that tidal currents on the Dogger Bank are insufficient to transport sediments (von Haugwitz et al. 1988). However, storm surge events may cause short - lived changes in the current velocity leading to sediment erosion, suspension and resettlement. These events are caused by intense depressions moving eastwards over the Norwegian Sea or NNS, which may occur at any time of the year but are more likely during the winter months. Figure 8-2: Annual current rose for Cygnus development Currents around the platform locations are predominantly orientated east-south-east to west-north-west. Towards the ETS pipeline tie-in location orientation is more south east to north west to south east as illustrated in the tidal rose which presents average annual currents (Figure 8-2) and Table 8-6 (maximum currents). Maximum surface current speeds reach 1.26ms -1 for a one year return event and 1.91ms -1 during a 100 year return event (Table 8-6). Average on spring tides is 0.3ms -1 (Fugro Geos 2008). At the measurement closest to the seabed a one year return event maximum current is 0.81ms-1 and during a 100 year event is 1.23ms -1. No average current speed at the seabed is available however, as a rule of thumb seabed currents are two thirds the strength of the surface current, therefore it can be assumed that the average seabed current is approximately 0.2ms -1. Source: Fugro Geos (2008) CF00-00-EB-108-00001 Rev C1 Page 98 of 300

Table 8-6 : Directional current speed profiles at depth Return Period Depth (metres) Direction (towards) (ms -1 ) N NE E SE S SW W NW 1 year 0 0.7 0.68 1.23 1.26 0.89 0.66 0.79 0.86 10 years 100 years 10000 years 4.4 0.67 0.66 1.19 1.22 0.86 0.64 0.77 0.84 11 0.63 0.62 1.11 1.14 0.81 0.6 0.72 0.78 21 0.45 0.44 0.79 0.81 0.57 0.43 0.51 0.55 0 0.85 0.85 1.53 1.58 1.12 0.81 0.9 0.96 4.4 0.82 0.82 1.48 1.53 1.08 0.79 0.87 0.93 11 0.77 0.77 1.39 1.43 1.01 0.74 0.81 0.87 21 0.55 0.54 0.98 1.01 0.72 0.52 0.58 0.62 0 1.01 1.02 1.85 1.91 1.35 0.97 1.01 1.06 4.4 0.98 0.99 1.79 1.85 1.31 0.94 0.97 1.03 11 0.92 0.92 1.68 1.73 1.22 0.88 0.91 0.96 21 0.65 0.65 1.19 1.23 0.87 0.62 0.65 0.68 0 1.35 1.38 2.53 2.61 1.84 1.31 1.24 1.28 4.4 1.31 1.34 2.45 2.53 1.78 1.27 1.2 1.24 11 1.22 1.25 2.29 2.37 1.67 1.18 1.12 1.16 21 0.87 0.89 1.62 1.68 1.18 0.84 0.8 0.82 Source: GDF SUEZ E&P UK 2011 8.3.2.3 Waves The Dogger Bank is exposed to substantial wave energy throughout the year with waves often breaking on parts of the bank during storm conditions. The shallow plateau of the Dogger Bank plays a part in absorbing wave energy from northerly storms. Given the water depth (assume 25m chart datum plus 3m tide and surge), there will be relatively frequent disturbance of seabed sediment due to wave orbital motions. Simple linear wave theory predicts that waves with a significant wave height of 4m will generate near-bed motions of 0.5 to 1.0ms -1. Such wave conditions can occur in all months of the year and are probably exceeded about 2 to 5% of the time (Ministerie van Verkeer en Waterstaat 2008, Department of Energy 1991). Considerably more severe motions, of 2 4ms -1, are generated in extreme storms with return periods of 1 year to 100 years. For these return periods significant wave heights are likely to be in the range of 6 10m (HSE 2001, HSE 2005). 8.3.3 Potential Impact Identification Tides, currents and waves are not directly impacted by oil and gas activities; however, the construction and production activities at Cygnus have the potential to affect water quality. Additionally tides, currents and waves will have an indirect effect on some project aspects and their impacts on environmental receptors, for example, by influencing the dispersion of drill cuttings, chemical discharges and accidental spills. The EIA identified that during the project life cycle the activities listed in Table 8-7 have the potential to interact with water resources. CF00-00-EB-108-00001 Rev C1 Page 99 of 300

Table 8-7 : Water resources impact identification Project Activity Aspect Potential Impact Construction Physical presence and movements of vessels Drilling of wells Installation of infrastructure Production Presence of platform Physical presence and movement of transportation Produced water Maintenance of platforms, pipelines and wells Accidental Events Spill of chemicals or hydrocarbons (<1 tonne) Spill of chemicals or hydrocarbons (>1 tonne) Discharge of sewage, grey water, food waste & drainage water Positioning structures on seabed e.g., jack-up legs Use of thrusters in shallow water Discharge of chemicals (including WBM) Discharge of reservoir hydrocarbons Discharge of chemicals Trenching Concrete mattressing and rock material Positioning structures on seabed e.g., platform, other subsea structures, and anchors Discharge of sewage, grey water, food waste and drainage water Discharge of reservoir hydrocarbons Discharge of chemicals Chemical, diesel or condensate spill Deterioration in water quality Increased suspended sediment loads & turbidity Deterioration in water quality Deterioration in water quality Increased suspended sediment loads & turbidity Deterioration in water quality Deterioration in water quality. In general, these aspects have only two potential impacts on water resources; the potential to degrade water quality and the potential to increase suspended sediment loads and turbidity. The EIA concluded that activities have the potential to create both the impacts, generally on a site specific basis (i.e., effects restricted to the project area). Some of the accidental events assessed potentially have a much wider area of impact e.g., the local or wider region. The magnitude of the impacts vary from low to high depending on the activity but all impacts are restricted to short -term effects. The assessment is provided in Section C of Appendices 2.2-2.4. 8.3.4 Mitigation Measures All project associated vessels will have and implement a written waste management plan compliant with the International Convention for the Prevention of Pollution from Ships (1973/1978) (Marpol 73/78) and its Annexes. As per Regulation 9 (Annex V, 1995) all vessels over 400 tonnes will have and maintain a Garbage Record Book. The plan will establish designated waste storage areas and implementation of the plan will ensure all waste is contained and stored away from open drains. All liquid waste will be stored with secondary containment. Paper and food wastes will be disposed of in a manner that is compliant with the relevant CF00-00-EB-108-00001 Rev C1 Page 100 of 300

regulations. Solid wastes will be compacted where possible and stored for appropriate disposal ashore. All project associated vessels will work to International Maritime Organisation (IMO) standards. GDF SUEZ E&P UK are currently considering sewage treatment options for the Cygnus A hub. Where possible they will endeavour to follow industry best practice for the region. Selections of chemicals will be made in accordance with the CEFAS ranked list, where chemicals ranked as lower potential hazards are preferentially chosen. Chemical use will be monitored daily during construction to allow more refined and efficient use. Where possible, products will be recycled to minimise discharge quantities. Only chemicals approved under the relevant Offshore Chemicals (Amendment) Regulations 2011 chemical permits (i.e., PON15B, PON15C or PON15D) will be discharged. Accidental spills will be kept to a minimum through the use of good practice codes, collision avoidance and fuel handling and transfer procedures. Management controls will be in place to reduce accidental events and eliminate bunkering spills e.g., bunkering will only be conducted during day light and in good weather; continuous monitoring during offloading; and hoses will be equipped with one-way valves. In addition all staff and contractors will be required to undertake training and maintain good housekeeping standards. GDF SUEZ E&P UK will have an OPEP in place to mitigate against accidental hydrocarbon spills associated with the proposed drilling and production activities. This will be prepared in accordance with the Oil Pollution Preparedness, Response and Co-operation Convention Regulations 1998, the Offshore Installations (Emergency Pollution Control) Regulations 2002 and updated guidance provided by the DECC in response to the Macondo Prospect incident in the Gulf of Mexico. The impacts of hydrocarbon spills are greatest for seabirds and as such the mitigation measures for fuel, condensate and chemical spills are discussed in detail in Section 9.4.3. 8.3.5 Residual Impact Significance Assessment Deterioration in water quality No residual impacts were identified for water quality. The following assessment is provided to explain why this impact was not brought forward for assessment. Offshore oil and gas drilling operations have the potential for impacts on water quality through possible addition of hydrocarbons, trace metals or organic substances. During the Cygnus construction and production phases pollutants will enter the marine environment from various different discharge streams e.g., chemical discharges, drainage water, sewage and produced water. However, any effects are likely to be highly localised and the environment will generally be able to rapidly assimilate the discharges and deal with them through natural bacterial action. Any increased concentrations of metals and hydrocarbons from offshore drilling operations are unlikely to be detectable above background levels. In addition, improvements in chemical formulations due to the Offshore Chemical Regulations mean that many chemicals discharged into the environment no longer contain heavy metals or bioaccumulating products. Taking proposed mitigation measures into consideration, the EIA concluded that there will be no residual impact on water quality as a consequence of the discharge of chemicals or hydrocarbons. Increased suspended sediment loads Three activities of the construction phase of the project have the potential to disturb seabed sediments, increasing suspended sediment loads in the water column. These are: The use of thrusters in shallow water Pipeline trenching Installation of platforms and positioning structures on the seabed e.g., manifolds, concrete mattressing and rock protection As discussed in Section 5.2.3.2, the effects of DP vessel thrusters are likely to be discernible above background levels of turbulence up to 14m below the sea surface. At the shallowest section of the pipeline route the water depth is 15.99m (Gardline Environmental 2011a), which would leave a 2m difference between the potential zone of impact and the seabed. In reality, the effects of the thrusters are unlikely to dissipate exactly at the 14m mark and as there is a relatively short distance between this point and the seabed it is thought not impossible that the turbulence created by the thrusters could disturb the seabed along this section of the pipeline route (up to approximately 12km), causing increased suspended sediment loads. CF00-00-EB-108-00001 Rev C1 Page 101 of 300

Although the placement of concrete mattresses, rock protection and structures on the seabed will cause disturbance, it is expected that suspended sediments will return to normal as soon as the activity ceases. Trenching will disturb a maximum of 9,000m 3 of sediments per kilometre along the export route and 6,000m 3 per kilometre along the intra-field route. Approximately 3.5km of pipeline will be trenched each day. The majority of the sediment will be piled on either side of the trench but some of the finer fractions will be suspended in the water column, increasing suspended sediment loads. Sediment particle size analysis indicates that sediments along the pipeline route are predominantly sand (60µm to 2mm). The proportion of silt (2µm - 60µm) varies depending on location and generally corresponds with water depth. For example, along the intra-field route the silt ratio is approximately 2.8%, along the first half of the export route from Cygnus A the silt ratio is approximately 2% and in the deeper section of the export route silt ratios range from 3.8% to 9.7% (see Section 8.4.2.3 and Gardline Environmental 2011a). Using these ratios and assuming a trenching speed of 3.5km per day, approximately 588m 3 of silt will be suspended in the water column per day along the intra-field route and between 630m 3 and 2,205m 3 per day along the export route. As demonstrated in Table 8-8, the terminal velocity of sand (particle size of 2mm) is such that it will settle out of suspension quickly (within a minute) along the route. Finer particles (2µm-60µm) will remain in suspension for significantly longer and will be deposited far down - current of the site of disturbance, over a wider area, ensuring a thinner (possibly undetectable) layer of deposition. Table 8-8 : Suspended sediment settling periods Particle Diameter Terminal Velocity (mm/s) Time to Fall 1m 5m 20m 2µm 0.002 5.8 days 29 days 116 days 60µm 1.75 9.5 minutes 47.6 minutes 3 hours 2mm 216 4.63 seconds 23 seconds 1.5 minutes It has not yet been determined whether a DP vessel, anchor lay barge, or a combination of both will be used to lay the pipeline. If a DP vessel is used, both sources of increased suspended sediment loads will occur within the same time frame. Limited research has been conducted into the effects of pipeline installation on sediment loading, but a comparable impact on water quality can be found in the marine aggregate industry. Often, as marine aggregate is extracted, the water/aggregate mix is passed over coarse mesh screens to increase the gravel content. The removed sand and silt is rejected overboard where it forms a sediment plume in the water column. The plumes are created over a six to eight hour period, depending on the size of the cargo. Monitoring has shown that the increased suspended sediment loads are transient, with concentrations of sediments returning to background levels within 6-7 tidal cycles (Marine Aggregate Licence Area 430: East of Southwold, Compass Hydrographic Surveys Ltd 2004). The suspended sediment concentrations created by activities at Cygnus are unlikely to be as high as those created by the aggregate industry. It is considered that disturbances from DP vessels are likely to be similar to, or less than, disturbance from storm conditions on the Dogger Bank. Trenching activity will be of short duration; one to two months, so any disturbance will be transitory, with concentrations returning to background levels within a few days to a week. Consequently the residual impact on the water column has been categorised as of low significance. CF00-00-EB-108-00001 Rev C1 Page 102 of 300

8.4 SEABED CONDITIONS 8.4.1 Baseline Data Sources The following data sources have been used to inform the baseline: Published report on geology of the SNS: Cameron et al. (1992) 2011 survey data for the platform sites and pipeline routes (Gardline Environmental 2011a,b,c) Site survey data collected for existing gas installations in the region e.g., Cavendish (Fugro Survey Ltd 2003), Gordon (Fugro Survey Ltd 2003), Humphrey (Gardline Environmental 2006), Monroe (Gardline Environmental 2003) and Wingate (Wintershall 2010). 8.4.2 Existing Baseline 8.4.2.1 Bathymetry The majority of the SNS lies within the shallow water of the southern embayment of the North Sea where water depths are generally less than 50m. The maximum water depth is 98m at Silver Pit, which is just south of the Dogger Bank area. The Dogger Bank, a t its highest point, is 15m below sea level (Cameron et al. 1992). The proposed Cygnus A platform location lies on the northern slope of the Dogger Bank in water depths of 22.6m LAT. The site is gently undulating with a general gradient of less than 1º The proposed export pipeline route starts at Cygnus A and heads in a south westerly direction across the Dogger Bank and beyond to the ETS pipeline. The top of the bank has limited change in relief, with depths ranging from 21.8m near Cygnus A to 15.7m on top of the bank. Around KP23 the edge of the Dogger Bank is marked by a steep slope from less than 18m deep to over 26m deep, reaching a depth of 48.8m at the ETS pipeline (Gardline Environmental 2011a). The seabed of the proposed intra-field pipeline route between Cygnus A and B ranges in depth from 21m to 23m. Water depth at Cygnus B is 21m deep. Bathymetry at the proposed platform sites and along the pipeline routes is illustrated in Figures 8-3 to 8-5. 8.4.2.2 Seabed geology The upper sediment layers in the SNS are the result of a series of glaciation events occurring during the Pleistocene epoch of the Quaternary period, occurring from 1.8 million years to 10,000 years before present (BP). Overlying these Pleistocene deposits are terrestrially derived, m ore or less mobile, recent (Holocene) muds, sands and gravels of the Holocene epoch, 10,000 years BP to present (Cameron et al. 1992). Generally Holocene sands dominate the shallow seabed geology around the proposed platform locations and along the first 33km of the export route, with the Bolders Bank Formation becoming more prominent as the route progresses towards the ETS pipeline. The base of the sands ranges from 17m at the proposed platform locations to 0.45m below seabed at KP33. Pleistocene Tills underlay the sands around the platform locations and along the first 10km of the export route. An intermittent layer of peat at the base of the Pleistocene Till was also identified along the pipeline route. From KP10 to KP30 the Holocene sands are generally 10m to 16m thick. At KP30 the base of the Holocene sands shallows to 1.5m and finally thins out around KP33. As the sand layer disappears, the firm to very stiff clay of the Bolders Bank Formation beneath becomes more prominent reaching a maximum depth of 4.8m below seabed. From KP33 to the ETS pipleine at KP51 the Holocene sands form a thin overlaying layer of surface sediments, which never achieve a thickness greater than 0.7m. The more prominent Bolders Bank Formation sediments, evident from KP33 onwards comprise firm to stiff silty clay that becomes stiff to very stiff gravelly clay with depth (Senergy S&G 2011). CF00-00-EB-108-00001 Rev C1 Page 103 of 300

Figure 8-3 : Bathymetry - proposed Cygnus A location Source: Gardline Environmental (2011b) CF00-00-EB-108-00001 Rev C1 Page 104 of 300

Figure 8-4 : Bathymetry - Proposed Cygnus B Location Source: Gardline Environmental (2011c) CF00-00-EB-108-00001 Rev C1 Page 105 of 300

Figure 8-5 : Bathymetry - Proposed pipeline routes Source: Gardline Environmental (2011a) CF00-00-EB-108-00001 Rev C1 Page 106 of 300

8.4.2.3 Surface sediments There are subtle differences in the sand fraction between the shallower water on top of the Dogger Bank and sands in the deeper waters to the south of the Bank. Sands on top of the bank are marginally coarser, moderately well sorted sand, and are expected to have a greater mobility than those at the base of the bank. In the lower energy deeper water, sands are consistently finer (Gardline Environmental 2011a, b, c). Cygnus A Sediment samples were acquired at nine stations within the vicinity of the proposed Cygnus A platform location as illustrated on Figure 8-3. Particle size analysis was undertaken using a Malvern Mastersizer particle sizer in addition to wet and dry sieving. Surface sediment consists mainly of fine to medium sand with differing levels of shell debris (see Figure 8-6). There are some areas to the west and south west of the proposed platform location where sediments incorporate more of a gravel component. It was found that particle size was relatively constant across the area with the majority of the stations sampled containing between 95.7% and 99.8% sand sized material (e.g., >60µm and < 2mm). Two stations to the south west of the proposed Cygnus A location showed lower fractions of sand due to high proportions of gravel (both over 60%). For all other stations the proportion of gravel was less than 4.3%. Table 8-9 presents the particle size distribution. The surface sediment samples were assessed using the sediment classification system of Folk, with size class descriptions based on the Wentworth scale, as per the British Geological Survey (BGS) 1:250000 seabed sediment series. Most stations were moderately or moderately well sorted find sand with exceptions at the two stations with high gravel components which were classified as poorly sorted very coarse sand (Gardline Environmental 2011b). Table 8-9 : Summary of surface sediment particle size distribution for Cygnus A location Station Mean size (mm) Sorting % Fines % Sands % Gravel 8649ENV1 2.346 Poor 0.2 40.3 59.4 8649ENV2 0.213 Moderately well 0 97.8 2.2 8649ENV13 0.188 Moderately well 0 87.1 2.9 ENV2 0.193 Moderately 0 95.7 4.3 ENV3 0.195 Moderately well 0 98.1 1.9 ENV4 0.192 Moderately well 0 98 2 ENV5 0.193 Moderately well 0 99.8 0.2 ENV6 0.172 Moderately well 0 98.2 1.8 ENV7 1.724 Poor 0 37.3 62.7 Minimum 0.172 Poor to 0 37.3 0.2 Maximum 2.346 moderately well 0.2 99.8 62.7 Mean 0.602 0 84.6 15.4 Standard Deviation 0.827 0.1 26.3 26.3 Source: Gardline Environmental (2011b) Cygnus B Sediment samples were acquired at ten stations surrounding the Cygnus B platform location (see Figure 8-4). Sediments at the Cygnus B location were predominantly fine to medium sands with shell fragments, gravel and some cobbles in seabed depressions (Figure 8-6). There was variability in the particle size distribution across the samples; sand ranged from 62-99.3% of the composition of the samples taken with fine material absent at all but one location. Gravels ranged from 0.7-7% of CF00-00-EB-108-00001 Rev C1 Page 107 of 300

the samples taken at seven locations, with two sample sites (ENV5 and ENV 8) having much higher volumes of gravel (38% and 29.1% respectively). ENV5, ENV8 and ENV3 were identified as being within seabed depressions. The particle size distribution is presented in Table 8-10 below. Stations with less than 7% gravel are considered fine sands under the Wentworth classification with the majority of these sites being moderately well sorted. Further classification under the Modified Folk system differentiates on the basis of increased gravel and shell fractions. This resulted in the majority of sites being classified as slightly gravelly sand or gravelly sand. Only ENV5, with the highest gravel content, was classified as sandy gravel. The three sites with high gravel concentrations were considered to be poorly or very poorly sorted (Gardline Environmental 2011c). Table 8-10 : Summary of surface sediment particle size distribution for Cygnus B location Station Mean size (mm) Sorting % Fines % Sands % Gravel 8649ENV1 0.213 Moderately well 0 97.8 2.2 8649ENV15 0.197 Moderately well 0 99.1 0.9 ENV1 0.199 Moderately 0 96.0 4.0 ENV2 0.188 Moderately well 0 98.5 1.5 ENV3 0.228 Poor 0 93.0 7.0 ENV4 0.215 Moderately well 0 99.3 0.7 ENV5 1.250 Very poor 0 62.0 38.0 ENV6 0.188 Moderately well 0 98.0 2.0 ENV7 0.201 Moderately 0 95.4 4.6 ENV8 0.811 Very poor 2 68.9 29.1 Minimum 0.188 Very poor to 0 62.0 0.7 Maximum 1.250 moderately well 2 99.3 38.0 Mean 0.369 0.2 90.8 9.0 Standard Deviation 0.364 0.6 13.6 13.2 Source: Gardline Environmental (2011c) Export pipeline route Sediment samples were acquired at twelve stations along the export pipeline route to inform the EIA. Surface sediments along the route are relatively variable. To the north east of the survey line, close to the location of the Cygnus A platform, the sediment is medium to coarse gravel. Further south (KP6 to 25) is fine compact sand with shell fragments. Further along the pipeline KP31 was very gravelly, medium to coarse sand with the remaining length of the pipeline route from KP 33-50 described as fine sand with varying degrees of gravel and shell material. The particle size analysis summarized in Table 8-11 identified that the majority of samples contained between 79.6% and 99.7% sand-sized material. Only the station closest to the proposed location of the Cygnus A had a lower proportion of sand, due to the higher volume of gravel; 60.8% compared with < 12% for all other stations. Silt constitutes less than 2% of the sediments for the first half of the route from Cygnus A and between 3.8 to 9.7% for the last half of the route where the water depths are deeper (generally greater than 30m) (Gardline Environmental 2011a). CF00-00-EB-108-00001 Rev C1 Page 108 of 300

Intra-field pipeline route The sediments sampled closest to the two platform locations during the intra -field pipeline survey, were found to be fine sand with occasional shell fragments. Sediments from the centre of the pipeline were identified as sandy gravel comprised mainly of shell fragments. This finding was supported by the particle size analysis which identified that the sample towards the centre of the pipeline differed for the others with a high proportion of gravel (47.1%). The relatively shallow nature of these stations resulted in low proportions of fines (Gardline Environmental 2011a). The particle analysis is summarised in Table 8-11. Table 8-11 : Summary of surface sediment particle size distribution for pipeline routes Station Export Pipeline Mean size (mm) Sorting % Fines % Sands % Gravel ENV1 2.346 Poor 0.2 39.1 60.8 ENV2 0.213 Moderately well 0 98.7 2.2 ENV3 0.214 Moderately well 0 99.6 0.4 ENV4 0.235 Moderately well 0 99.7 0.3 ENV5 0.155 Moderately well 4.7 84.6 0.7 ENV6 0.465 Poor 3.8 89.1 7 ENV7 0.212 Moderate 4 93.6 2.4 ENV8 0.324 Moderate 1.9 96.8 1.3 ENV9 0.285 Poor 5.2 94.8 0.1 ENV10 0.304 Very poor 6.6 81.5 11.9 ENV11 0.251 Very poor 9.7 79.6 10.7 ENV12 0.228 Moderate 5.6 94.4 0 Intra-field Pipeline ENV13 0.188 Moderately well 0 97.1 2.9 ENV14 2.091 Poor 0.4 52.5 47.1 ENV15 0.197 Moderately well 0 99.1 0.9 Minimum 0.155 Very poor to 0 39.1 0 Maximum 2.345 moderately well 9.7 99.7 60.8 Mean 0.514 2.8 87.3 9.9 Standard Deviation 0.698 3.1 18.1 18.4 Source: Gardline Environmental Limited (2011a) CF00-00-EB-108-00001 Rev C1 Page 109 of 300

Comparison with existing surveys The particle size distribution data for the proposed Cygnus A platform site and pipeline routes have been compared with existing data acquired from the Dogger Bank region. Table 8-12 summarises the existing survey data and shows that the sediments in the Cygnus project area are typical for the Dogger Bank and reflect the energy impacting on the seabed. The predominant sediment types are sands, with varying silt and gravel contents. Representative photographs of the different sediment types within the project area are provided in Figure 8-5. Table 8-12 : Comparison of sediment characteristics across the Dogger Bank Site Classification Mean size (mm) Sorting % Fines % Sands % Gravel Reference Cygnus Development Cygnus A Cygnus B Pipeline Top of the Dogger Bank Previous Cygnus A Location Fine sand to granule Fine sand to granule Fine sand to granule 0.602 0.369 0.514 Poor to moderately well Very poor to moderately well Very poor to moderately well 0 84.6 15.4 0.2 90.8 9.0 2.8 87.3 9.91 Fine Sand 0.189 Poor 0 92.49 4.84 44/12a-C Fine Sand 0.199 Moderately Well 0 96.7 3.3 44/12a-D Fine Sand 0.371 Poor 0.1 82.7 17.2 44/12a-E Fine Sand 0.204 Moderately Well 0 96.9 3.1 44/12a-F Cygnus Exploration Well Mainly Fine Sand 0.69 Moderately Well 0.2 84.5 15.4 Fine Sand 0.2 Moderately 0 95.8 4.2 Cavendish Sand - Well 0.02 98.78 1.2 Gordon Sand - Well 0.03 98.11 1.85 Humphrey Fine Sand 0.216 Moderately Well 0 97.8 2 Monroe Fine to Coarse Sand - Moderately Well 0.36 94.34 5.29 Gardline Environmental (2011b) Gardline Environmental (2011c) Gardline Environmental (2011a) UTEC Survey Ltd (2009a) Gardline Environmental (2008a) Gardline Environmental (2008b) Gardline Environmental (2008c) Gardline Environmental (2008d) Gardline Environmental (2005) Fugro Survey Ltd (2003) Fugro Survey Ltd (2003) Gardline Environmental (2006) Gardline Environmental (2003) CF00-00-EB-108-00001 Rev C1 Page 110 of 300

Figure 8-6 : Photographs of Seabed taken during Environmental Baseline Survey Source: Gardline Environmental (2011a, b, c). Top left: Cygnus A location. ENV 7 Gravel with sand and shell debris and hermit crab with hydroid. Top right: ENV 3 Sandy sediment with shell debris and nut crab (Ebalia sp.) Middle left: Cygnus B ENV2 Rippled sand with occasional shell fragments, crustacean and chordata. Middle right: Cygnus B ENV9 Gravel and shell fragments overlying sand. Bottom left: Intra-field Pipeline ENV14 Rippled sandy sediment and fine gravel with shell debris. Bottom right: Export pipeline. ENV 5 Sandy sediment and shell debris with common starfish and some bioturbation CF00-00-EB-108-00001 Rev C1 Page 111 of 300

8.4.2.4 Sediment Contamination Background concentrations of hydrocarbons and heavy and trace metals in sediments generally increase from the SNS to the NNS. This trend is linked to the spatial distribution of sediment type, with higher background concentrations generally found in fine sediments, such as mud and silt, rather than coarser sediments, such as sands and gravels. This is due to fine sediments having a greater surface area and adsorptive capacity. In addition, the strong currents in the SNS lead to greater dispersion and dilution of chemicals after discharge. In general contamination of offshore sediments is decreasing and tends to be very localised and focused around point discharge sources such as oil and gas installations (DECC 2011c). Sediments within 500m of an installation are typically contaminated by hydrocarbons and a range of heavy and trace metals. This is due to the rapid fall-out of heavy elements from discharges such as drill cuttings and produced water (DECC 2011c). The sediment samples acquired from the twenty nine stations across the Cygnus project were analysed for hydrocarbon and trace and heavy metal contamination (Gardline Environmental 2011a, b, c). A discussion of the results is presented below. Cygnus A Total hydrocarbon concentrations (THC) ranged from 1.5µg.g -1 to 5.2µg.g -1, with higher concentrations identified in samples with greater proportions of fines. This is consistent with expected levels for the Dogger Bank and SNS; background concentrations reported by UKOAA (2001) are 11.39µg.g -1 for stations at least 5km from an oil or gas installation. As THCs are below background concentrations it is considered that the source is likely to be a result of well weathered biogenic and petrogenic hydrocarbons potentially from natural seeps, shipping and oil and gas exploration (Gardline Environmental 2011b). A similar pattern was observed in concentrations of n -alkanes. Concentrations were generally low across the site, ranging from 0.028µg.g-1 to 0.126µg.g -1 (Stations ENV5 and 8649ENV13 respectively). The carbon preference index and pristane/phytane ratio suggests that the n -alkanes present are from biogenic sources but with a low level of petrogenic sources. 8649ENV13 showed the highest n-alkane and joint highest pristane concentrations. It also had the highest total polyaromatic hydrocarbon (PAH) concentration of 0.013µg.g -1. PAHs are generally produced from pyrolytic sources (e.g., the combustion of organic materials such as forest fires or offshore from flare stacks) or the discharge of petroleum hydrocarbons associated with localised drilling activities, and are normally transported into sediments via atmospheric fallout or river runoff. Mean PAH concentrations for locations greater than 5km from an oil or gas installation in the SNS is 0.306µg.g- 1 t (UKOAA 2001) and the concentration at which a toxicological effect is likely to be seen is 4.022µg.g -1 (Long et al. 1995) therefore the concentration of PAHs is not considered likely to have an impact on the surrounding environment. To establish the baseline for heavy and trace metal contamination, samples were analysed for typical metals associated with oil and gas activity. Several heavy and trace metals are found in elevated concentrations within drilling fluids or produced water discharges from oil and gas installations. The most common metal contaminants of sediments are barium, chromium, lead and zinc. Barium is the most abundant metal found in drilling related discharges due to its use as a weighting agent in WBM in the form of barite. Natural barium levels across the project area were relatively low ranging from 151µg.g -1 to 254µg.g -1. UKOAA (2001) indicated that background concentrations of barium are 302.95µg.g -1 therefore concentrations are considered to be background at all nine stations. Most of the remaining metals analysed 1 were below their apparent effects threshold (AET) and at or near background concentrations (Gardline Environmental 2011b). Arsenic, nickel, chromium, vanadium and zinc were statistically correlated with mean particle size showing higher concentrations where gravel proportions were greater (Gardline Environmental 2011b). Cygnus B Sediment samples from the Cygnus B location had THC concentrations below or close to the background concentrations reported by UKOAA (2001). These ranged from 1.7µg.g -1 to 5.1µg.g -1. The sample from ENV8 (926m south of the Cygnus B location) was 11.39µg.g -1, which is more in 1 Arsenic, chromium, cadmium, copper, lead, mercury, nickel, tin, vanadium, zinc, aluminium and iron CF00-00-EB-108-00001 Rev C1 Page 112 of 300

line with the 95th percentile of the UKOAA data (Gardline Environmental 2011c). This sample was the only location to have any fine material however it is not considered that this is likely to be the only reason for the two fold difference in THC. The nearest historic well locations are 2.3km east and 2.3km southeast; the prevailing current direction is east south-east to west north-west, therefore it is possible that residue from these wells has travelled. It is not considered however, that this will have an impact on the surrounding benthos as hydrocarbons are unlikely to show a significant environmental impact (SEI) until concentrations exceed 50µg.g -1 (OSPAR 2005). Further analysis of the THC indicates that it is highly weathered, and largely from petrogenic sources. At ENV8 where concentrations of THC are higher, similar results were identified with the hydrocarbons being too weathered to be able to clearly identify if the source was anthropogenic. N-alkane concentrations ranged throughout the sample area with the mean as 0.055µg.g -1 (SD +0.039). This is below the UKOAA background concentration of 0.33µg.g -1. CPI concentrations were consistent with those found at the Cygnus A location. The low concentrations of n-alkanes, pristine and phytane make interpretation of these results complex, however it is considered that they represent a low level diffuse mixture of petrogenically and biogenically derived alkanes (Gardline Environmental 2011c). PAH concentrations were below the limit of detection at seven of the sample locations with the highest being 0.01µg.g -1 at ENV7 (1426m east south-east of the Cygnus B location). Concentrations indicate traces of anthropogenic contamination consistent with oil and gas development. THC and n-alkane concentrations do not correlate with particle size at the Cygnus B site, however concentrations are consistent with diffuse distributions in the area and are unlikely to have any detrimental effect on benthic fauna. Barium concentrations ranged at the Cygnus B location from 160-236µg.g -1 ; ENV3 and ENV6 (1,172m east and 478m south east of the Cygnus B location respectively) were identified as above the UKOAA (2001) background concentration of 218µg.g -1. Water based drilling muds can contain up to 720µg.g -1 therefore it is considered that these results suggest an absence of contamination from drilling muds or cuttings. The majority of metals were found in concentrations below the AET and at or near background concentrations were listed. Vanadium was observed at 71.7µg.g -1 at ENV3, which is above the UKOAA 95th percentile of 41.2µg.g -1 as well as in elevated concentrations at ENV2. ENV3 also had higher concentrations of chromium and the highest concentrations of barium, mercury and lead. Hydrocarbon concentrations at ENV3 are not elevated and there was no difference in fine materials to explain this variation in metals concentrations. The nearest well is over 2.8km away. The elevated vanadium concentrations are unlikely to have an impact on the faunal community as it is not highly bioavailable (Gardline Environmental 2011c). Export and intra-field pipeline routes THC along the export pipeline ranged from 0.5µg.g -1 to 14.3µg.g -1 with the highest concentration, found at KP36.8 (ENV 10), being significantly different from the other samples. This site is the only location where THCs exceed the UKOAA (2001) defined background concentrations, therefore it is possible that ENV10 may have been subject to previous contamination. However, as it is below 50µg.g -1 it is unlikely to have an impact on the surrounding benthos (OSPAR 2005). Further analysis of THC indicates that at all stations other than ENV10, sources of THC are likely to be well weathered and biodegraded petrogenic hydrocarbons. N-alkane concentrations, CPI, pristane and phytane concentrations support this finding although indicate that THC is also from low level petrogenic sources. At KP36.8 (ENV10) it is considered that the source of the higher THC may be a low-level presence of well-weathered diesel. Average PAH concentration for the route was 0.055µg.g -1 (+0.054SD) with concentrations being consistently lower at stations in shallower water depths. All concentrations greater than 0.01µg.g -1 were encountered at sample locations deeper than 30m with the highest recorded at KP33 (ENV7). All concentrations were below the background concentration for the SNS of 0.306µg.g -1 (UKOAA 2001). Barium concentrations ranged between 151µg.g -1 and 269µg.g -1, which is below the background concentration of 302.95 µg.g -1 (UKOAA 2001) indicating no evidence of anthropogenic contamination. The majority of metals were found to be below the background concentrations; however concentrations of vanadium at KP31 (ENV6) and KP34.5 (ENV8) to KP 43.5 (ENV11) were higher CF00-00-EB-108-00001 Rev C1 Page 113 of 300

than the background concentration. At KP31 (ENV6) the concentration exceeded the AET (Gardline Environmental 2011a). In addition, arsenic concentrations were close to the upper limit of what is considered the background concentration. A correlation was identified between the concentration of metals and the mean grain size, indicating that stations with higher proportions of fines were naturally accumulating more metals. This is in contrast to the findings of the Cygnus A site survey where metal concentrations were positively correlated with grain size. The results for the intra-field pipeline were similar to those of the export pipeline, with all values being within the ranges described above. Comparison with other areas Hydrocarbon, n-alkane and metal concentrations for shallower sites are generally consistent with those of other surveys undertaken in the area, however, CPI values for the pipeline indicate higher petrogenic sources than other surveys. It is considered that these higher concentrations are consistent with higher proportions of fine material rather than a point source of anthropogenic hydrocarbons (Gardline 2011b). Similarly the deeper sites indicated higher concentrations of metal when compared to other surveys of the area, but this is consistent with the higher concentration of fine material and organic matter allowing greater adsorption and retention than larger grain sizes. In 2009 seabed surveys were conducted in the area to assess the potential impact of the initial proposed Cygnus A location. 176 tonnes of barite were discharged at that site in the first quarter of 2006 as part of the exploration drilling programme and it appeared that three years later, the metal had not remained resident in the sediments but had dispersed over a wider area (UTEC Survey Ltd 2009b). The barium had become undetectable above background levels and reflected the natural variations in levels expected for the sediment type. In addition, the majority of the barite (79-90%) remained insoluble, unavailable to marine fauna, and in its insoluble form is considered non-toxic (Gerrand et al.1999 in UTEC Survey Ltd 2009b). 8.4.2.5 Seabed Features Large depressions were noted within the project area of up to 3.5m deep, containing mega-rippled gravel (see Figure 8-8). These were likely to be produced as a result of marine flooding in the late Holocene transgression followed by erosion of the surrounding sediment which has left an exposed area of clay, silt and shell debris. When these have become exposed they cover the bottom of large scour depressions. These depressions were also noted along the intra-field pipeline route where they were described as discrete areas of gravel ripples. Depressions were also noted close to the intra- pipeline; two camera transects were undertaken the furthest points located 32m south south- of KP4.08 and 59m south south-west of KP3.96. The photos identified cobbles and boulder like formations in the centre of the depressions. These may be relic biogenic reefs with cemented sand worn smooth by the current. field with west and Figure 8-7 : Possible relic biogenic reef at Cygnus A location (CAM1 transect) Source: Gardline Environmental (2011b) No other seabed features or obstructions were noted at the proposed location of the Cygnus A and B platforms. The survey of the export pipeline route identified a number of seabed features. The route includes the transition from the edge of the Dogger Bank to the deeper water to the south west. The slope and deeper water has resulted in a different seabed type; more fine material was identified with occasional patches of gravel with a veneer of rippled sand (KP30.5 to KP31.45). A wreck and associated debris was identified between KP16.5 and KP17, approximately 335m northwest of the centre line. The wreck itself rises to 4.5m above the seabed with the largest debris being up to 1.1m above the seabed. CF00-00-EB-108-00001 Rev C1 Page 114 of 300

Other features noted during the survey include: The Cavendish to Murdoch pipeline consisting of a 10" export line with methanol piggy-back and fibre optic cable crossing the proposed route east to west at KP31.55. Numerous sand mounds from KP32.27 to KP 35.38, however camera investigations determined there was no apparent change in seabed type. Sand waves with approximate wavelengths of 100-200m cross the proposed route between KP35 and KP37.5. Trawler scars were also noted in the area, between KP43 and KP51.01. These were of various orientations and prominence. 8.4.2.6 Sediment Mobility Sediment transport studies undertaken by HR Wallingford (2002) suggest that the net sediment transport in the SNS is from south to north, parallel with the coastline. On the Dogger Bank, both wave and tidal activity are important factors in the movement of sediment, due to the shallow water. As discussed in Section 8.3.1, tidal velocities are low, with the average seabed current estimated to be approximately 0.2ms -1 and 0.3ms -1 at the surface, and under normal conditions are unlikely to erode or re-suspend sediments. Only when storm generated currents reinforce tidal currents are erosion and sediment movement likely to occur, which in the case of the Dogger Bank is mainly during winter months. The HR Wallingford (2002) study does indicate that during spring tides the maximum sediment grain size mobilised is 0.5 2mm. Particle size analysis for sediments in the project area (Tables 8-9 to 8-11) demonstrates that surface sediments are predominantly below this size range, and therefore it is likely they would mobilise during spring tides. CF00-00-EB-108-00001 Rev C1 Page 115 of 300

Figure 8-8 : Cygnus A - seabed features Source: Gardline Environmental (2011b) CF00-00-EB-108-00001 Rev C1 Page 116 of 300

8.4.3 Potential Impact Identification Table 8-13 identifies the project activities that have the potential to interact with seabed conditions. Table 8-13 : Seabed conditions potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movement of transportation Installation of infrastructure Positioning structure on seabed e.g., jack-up legs, platforms, other subsea structures and anchors Change/disturbance of surface sediments. Change in seabed topography Installation of infrastructure Discharge of chemicals Sediment contamination Physical presence and movement of transportation Trenching Concrete mattressing and rock material Use of thrusters in shallow water Rock material (rig stabilisation) Change/disturbance of surface sediments Change in seabed topography Change in seabed topography Possible scour around objects Change/disturbance of surface sediments Drilling of wells Discharge of cuttings Change in seabed topography Discharge of reservoir hydrocarbons Sediment contamination Discharge of chemicals (including WBM) Production Produced water Maintenance of platforms, pipelines and wells Accidental Events Overboard loss of equipment or waste Spill of chemicals and hydrocarbons (< 1 tonne) Spill of chemicals and hydrocarbons (> 1 tonne) Discharge of reservoir hydrocarbons Discharge of chemicals Dropped objects Chemical, diesel or condensate spill Chemical, diesel or condensate spill Sediment contamination Potential for small scour around object. Sediment contamination Sediment contamination In general, the EIA concluded that impacts would be restricted to the project site, would be of low to medium magnitude and would be anywhere from short-term to long-term in duration. The likelihood, spatial extent, magnitude, duration and significance of the impacts have been assessed in Section D of Appendices 2.2-2.4. 8.4.4 Mitigation Measures Footprints on the seabed will be minimised through careful design and where possible, by positioning drilling rig legs in existing footprints on return to the sites. Opportunities to reduce the CF00-00-EB-108-00001 Rev C1 Page 117 of 300

number of rig moves are currently being explored. Vessel operating procedures should ensure anchor drag is minimised. To reduce the impact of chemical discharges on the seabed, chemical selection will be made in accordance with the CEFAS ranked list, with chemicals ranked as lower potential hazards preferentially chosen. Only chemicals permitted through the relevant Offshore Chemical (Amendment) Regulations 2011 chemical permits and that have been subject to a risk assessment will be discharged. During drilling, daily recording of chemical use will be undertaken to allow more refined and efficient use of WBM which is typically discharged to the marine environment. Mud will be recycled throughout the drilling programme to minimise usage. Dead volumes in mixing pits will be minimised by using a cement liquid additive system to calculate the volume of fluid required for the job. Other measures to be undertaken by GDF SUEZ E&P UK during construction include, but are not limited to: Precise positioning of rock material by manoeuvring the fall-pipe with an ROV, allowing accurate berm profiles to be built up. Only using sufficient material e.g., concrete mattresses or rock for protection or stabilisation. Mitigation against accidental events includes conducting a debris clearance survey at the end of each construction period, ensuring that any significant objects are removed. Regular inspections will be undertaken to establish that all equipment is in good working order and accidental spills will be kept to a minimum through training, good housekeeping and through storage/handling procedures. Sumps and drains should catch accidental spill releases, and management controls will be in place to eliminate bunkering spills (for example, only bunkering during good light and in good weather). GDF SUEZ E&P UK will also ensure that a location specific OPEP is in place for the development. 8.4.5 Residual Impact Significance Assessment 8.4.5.1 Contamination of sediments The main sources of sediment contaminants is the WBM discharged directly to the seabed during drilling. Barite and bentonite, two of the main components of WBM, have been widely shown to accumulate in sediments. However, based on a comparison of the barium levels on sediments at the Cygnus exploration well pre- and post-drilling, showed no significant elevation in concentrations after three years, (Section 8.4.2.4), therefore the expected residual impact on sediments has been assessed as of low significance, i.e., only just detectable above background levels. If accumulation in sediments is noticeable, the heavy and trace metals are generally of low toxicity to marine organisms and have low bioavailability, i.e., they are unlikely to bioaccumulate. Therefore, the contamination is unlikely to result in significant toxicity to benthic communities (DTI 2001a). The EIA concluded that a loss of containment from the export pipeline or loss of well control has the potential to contaminate seabed sediments. In either case the overall residual impact was assessed to be of low significance. This is based on the fact that the impact would be localised, the ratio of condensate to gas is very low (1.9bbls/mmscf) and condensate, whilst more persistent in the environment than other hydrocarbons such as diesel, has a high proportion of light fractions which are readily biodegradable. Additionally, given the high energy environment in the project area, contaminated sediments are likely to be dispersed over a wider area, reducing the concentration levels at the site of impact. 8.4.5.2 Physical disturbance causing a change to surface sediments A number of project activities will impact the seabed either through compaction of surface layers or by physical disturbance, e.g., deposition, displacement and redistribution. A maximum of 1.46km 2 of seabed will be disturbed by construction activities, assuming that an anchor lay -barge is used for installation purposes. Where structures (such as the drilling rig and subsea equipment), bear down on the sediment there will be localised disturbance, compaction and disaggregation of sediments. Activities which physically penetrate surface sediments, e.g., trenching and positioning anchors, will bring underlying sediments to the surface. The Holocene sands dominate the surface sediments in the intra -field pipeline area therefore activities that penetrate the seabed to 2-3m are unlikely to cause a significant change in the sediment type at CF00-00-EB-108-00001 Rev C1 Page 118 of 300

the surface, although there may be some fining. The export pipeline route also crosses Holocene sands, however at KP33, these decrease in depth to 0.8m in places. Activities which penetrate to 2-3m may therefore bring the firm to stiff silty clay of the Bolders Bank formation to the surface. This will result in a slight change in local sediment type which may be noticeable for a short period. If it is determined that the anchor lay barge will be used to undertake the pipeline laying activities, anchor mounds will be generated from deposition of the anchors onto the seabed. Research undertaken for ConocoPhillips (BMT Cordah Ltd 2006) into the impacts of anchor mounds in the sandy sediments of the SNS found that: There was no evidence of anchor mounds at any of the ten sites investigated (water depths ranging from 28-34m) within one month of anchor retrieval At several sites the normal pattern of closely spaced sand ripples appeared to have been broken up, and at some sites there were increased amount s of shelly material on the surface It is anticipated that disturbance created by the anchors will be similar to that evident in the ConocoPhillips study. At present it has not been determined whether the trench will be mechanically or naturally backfilled. It is assumed that, if backfilling is undertaken mechanically, a similar pattern of disturbance may be visible after the trench has been filled e.g., broken sand ripples and higher quantities of shelly material. Any residual berms left by the trenching and backfilling process are likely to be similar in height and diameter to an anchor mound and it is assumed that they will disperse in a similar manner and timescale i.e., within a month. If naturally backfilling is considered a feasible option, an assessment of BAT and BEP will be completed and modellin g undertaken where appropriate. This assessment will be used to determine the potential impact on the environment and inform the decision as to the most suitable method. Section 6.1.3.5 determined that cuttings of thicknesses greater than 1mm cover a maximum area of 90,000m 2. The resulting increase of sediments will not be noticeable above general sediment movement and will therefore have a negligible impact on seabed conditions. The drill cuttings discharged directly at the seabed create a raised mound, which would change seabed topography and therefore potentially influence local sediment transport pathways and currents. It has been estimated that in the worst case scenario, drill cuttings discharged directly at the seabed will cover approximately 631m 2 at each drill centre (see Section 6.1.3.5); however, based on the evidence below, it is anticipated that they will be dispersed rapidly and possibly within one month. Significant erosion of cuttings piles occurs when the seabed current velocity exceeds 0.35ms -1 (UKOOA 1999) i.e., during storm events within the project area. This is supported by other operators experience in the SNS, where cuttings piles have been rapidly dispersed due to the strong currents in the region. For example: The environmental baseline survey of the 44/24b-7z exploration well of the Wingate site showed no evidence of a drill cuttings pile one year after drilling (Wintershall 2010). Survey work undertaken at the Gordon a nd Esmond Fields determined that although historical drilling has taken place, there are no mounds of cuttings or mud present (BHP Billiton 1998). ROV surveys of the seabed around the appraisal wells Munro and Topaz (Block 44/17b and 49/2a; GDF Britain Ltd 2004b, 2004c) and K3 (Block 44/23; ConocoPhillips (UK) Ltd 2005b) detected no signs of drill cuttings 16 days after drilling operations had ceased. Cygnus exploration well post-drilling seabed clearance survey undertaken two days after the drilling programme had completed found no evidence of debris on the seabed (Rudall Blanchard Associates 2008). Consequently it is to be expected that there will be no long-term retention of cuttings piles at the drill sites. Dispersed cuttings will be incorporated into surface sediments through general sediment mobility. The 2009 site investigation conducted for the previous Cygnus A site identified that although no distinct cuttings pile was noted around the Cygnus exploration well, sediment particle analysis showed the site had a distinct amalgam of unsorted fines from coarse silts through to clays indicative of fine drill cuttings of varying sizes (UTEC Survey Ltd 2009b). This suggests that a slight fining of sediments may be detectable within 300m of the wellheads as a consequence of drill cuttings discharges, but that this change is extremely localised. It is likely that CF00-00-EB-108-00001 Rev C1 Page 119 of 300

the development will affect at most 0.045km 2 of seabed from drill cuttings assuming individual drilling footprints will not overlap. The EIA also identified that the presence of concrete mattresses and rock material may cause scour depressions to form on the seabed. Concrete mattresses and rock berms are not tall structures, therefore the disruption to sediment transport pathways is likely to be minimal. Scour will not change surface sediments but it could reveal deeper lithologies. The areas most likely to suffer scour are those with highest currents, on the top of the Dogger Bank. Here the Holocene sands are relatively deep so it is considered unlikely that there will be a significant change in surface sediments as a result of scour. Based on the above, the EIA concluded that physical disturbance will have a low impact on the seabed. CF00-00-EB-108-00001 Rev C1 Page 120 of 300

9.0 IMPACTS ON BIOLOGICAL ENVIRONMENT This section describes the existing baseline biological environment, the impacts the Cygnus development will potentially have on this environment, how any impacts will be mitigated and qualifies the significance of any residual impacts. It follows the same structure as Section 8 and applies the methodology established in Section 4. The biological environment has been divided up into the following main areas: 9.1 PLANKTON Plankton (Section 9.1) Benthic ecology (Section 9.2) Fish and shellfish (Section 9.3) Seabirds (Section 9.4) Marine mammals (Section 9.5) Protected sites and species (Section 9.6) 9.1.1 Baseline Data Sources The following data sources have been used to inform the baseline: Information on plankton abundance and species distribution in UK waters is derived from the Continuous Plankton Recorder (CPR) surveys in the North Atlantic and North Sea: DTI (2001b). Offshore Energy Strategic Environmental Assessment (SEA): DECC (2009b, d). Other published literature references include: Riegman et al. (1990), Nielsen et al. (1993), Edwards and John (1995), Kröncke and Knust (1995) and Wieking and Kröncke (2001). 9.1.2 Existing Baseline Plankton communities form the base of the marine food web and are therefore of primary importance to the structure and functioning of the ecosystem. Plankton are defined as organisms that are unable to resist ocean currents and consist of any drifting plants (phytoplankton), animals (zooplankton) and bacteria (bacterioplankton) that live freely in the water column. Plankton abundance and species distribution is strongly influenced by factors such as depth, tidal mixing and temperature stratification of the water column, salinity, nutrient concentrations, the location of boundaries between different water masses i.e., fronts, and the presence of local benthic (bottom dwelling) communities (Edwards and John 1995). CPR surveys show that the most abundant groups of phytoplankton and zooplankton in the SNS are as follows: Phytoplankton: the dinoflagellate genus Ceratium dominates the phytoplankton community followed by the diatom genus Chaetoceros. Zooplankton: Copepods (crustaceans) dominate the zooplankton community, with small species being most abundant such as Para-Pseudocalanus spp., Acartia and the younger stages of Calanus. Echinoderm larvae are the second most abundant group (DTI 2001b). In the North Sea phytoplankton blooms (high concentrations of phytoplankton in an area caused by increased reproduction) occur in spring and to a lesser extent may occur again in the autumn. During the winter months, in periods of low light, phytoplankton growth is inhibited. This allows nutrient concentrations to build up as little or no primary production is taking place. When the water becomes stratified in the spring, nutrients in the photic zone result in a bloom of diatoms as growth and correspondingly reproduction are stimulated. On and around the Dogger Bank the community is distinctly different from the surrounding SNS, being in the main composed of smaller species. This is the result of a number of physical and hydrographic features including: CF00-00-EB-108-00001 Rev C1 Page 121 of 300

Shallower water on the Bank. Vertical mixing of the water column over at least part of the Bank throughout the year due to the presence of fronts, tidal currents and wave action (Riegman et al. 1990, Nielsen et al. 1993). The phytoplankton is dominated by the flagellates Chrysophyceae, Cryptophyceae, Dinophyceae, and Prymnesiophyceae (Nielsen et al. 1993). Phytoplankton production in the region of the Dogger Bank is high throughout the year, a large proportion of which remains unconsumed and thus settles to the seabed surface where it is available to benthic fauna (Kröncke and Knust 1995, Nielsen et al. 1993, Wieking and Kröncke 2001). Primary production is reported to remain high in the shallow waters throughout the winter, with a spring bloom commencing much earlier than in the surrounding nearby coastal waters. Zooplankton over the Dogger Bank are characterised by small, heterotrophic ciliates and flagellates, in contrast to the rest of the SNS which is characterised by the larger copepod zooplankton. Copepods are still an important component of the Dogger Bank zooplankton, but it also represents a mixing of two distinct communities: a coastal community where the copepod genus Acartia is important and an offshore community typified by the copepod genus Calanus (Nielsen and Monk 1998). The commonest species are Calanus finmarchicus, Paracalanus parvus, Oithona spp, Temora longicornic and Pseudocalanus elongate (GDF Britain 2005). 9.1.3 Potential Impact Identification This EIA has identified that during the project life cycle the activities listed in Table 9-1 have the potential to interact with plankton. Table 9-1 : Plankton potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and mo Installation of infrastructure Drilling of wells Drilling of wells Production Presence of platform Physical presence and movement of transportation Produced water Maintenance of platform, pipelines and wells Accidental Events Spill of chemicals or hydrocarbons (<1 tonne) Spill of chemicals or hydrocarbons (>1 tonne) Discharge of sewage, grey water, food waste & drainage water Discharge of chemicals (including WBM) Discharge of reservoir hydrocarbons Discharge of sewage, grey water, food waste & drainage water Discharge of reservoir hydrocarbons Discharge of chemicals Chemical, diesel or condensate spill Release of gas Organic enrichment leading to raised biological oxygen demand. May increase plankton populations changing balance of food chain. Potential toxic effects Organic enrichment leading to raised biological oxygen demand. May increase plankton populations changing balance of food chain. Potential toxic effects Potential toxic effects CF00-00-EB-108-00001 Rev C1 Page 122 of 300

The EIA concluded that there will be an interaction between the project activities and plankton during the project, but that any resulting impacts will be restricted to the project area. Changes to the baseline may be noticeable (i.e., magnitude of medium) but the duration of any impact will be short-term (up to two years). The likelihood, spatial extent, magnitude, duration and significance of the impacts have been assessed in Section E of Appendices 2.1 2.4. 9.1.4 Mitigation Measures Measures outlined in Sections 8.3.4 and 8.4.3 adopted to reduce and/or eliminate the toxic impacts of the development on water quality will also mitigate the potential impacts on plankton. These have not been repeated here but are listed in the previous sections and Appendix 2. In addition, all chemical discharges will be risk assessed and within the DECC permitted levels as per the relevant Offshore Chemical (Amendment) Regulations 2011 chemical permit i.e., PON15B, PON15C or PON15D. 9.1.5 Residual Impact Significance Assessment During construction, permitted chemicals will be discharged to sea either at the seabed from the well or pipeline, or at sea level from the drilling rig or construction vessels. Some chemicals used in drilling and pipeline commissioning often have the potential to cause toxic harm when discharged e.g., biocides or oxygen scavengers. In addition, if an accidental spill of greater than 1 tonne of hydrocarbons or chemicals were to occur during the project life cycle it is expected that the plankton community will suffer from toxic effects. Studies indicate that zooplankton appear to be the most vulnerable group to toxic effects of chemical discharges, whereas the phytoplankton and fish larvae tend to be more robust to any direct effects (GESAMP 1993). Plankton organisms are generally short lived however and recovery following a pollution induced population reduction is usually rapid. The metocean conditions in the region will ensure chemical discharges are rapidly diluted and dispersed, minimising the extent of any effects. As such, the impact of chemical discharges on marine ecology has been assessed as having a low impact. 9.2 BENTHIC ECOLOGY 9.2.1 Baseline Data Sources Primary site specific data for the proposed Cygnus A and B platform locations, the intra-field pipeline route and the export pipeline route were acquired by GDF SUEZ E&P UK 2011 (Gardline Environmental 2011a,b,c). In addition, survey data was also acquired in the wider field area during 2008 and 2005 to support appraisal and exploration drilling (UTEC Survey Ltd 2009b; Gardline Environmental 2008a,b,c,d; Gardline Environmental 2005). All survey extents are provided in Section 4.1.3. Secondary data sources include: Published literature on benthic community structures: Wieking and Kröncke (2001), Connor et al. (2004), Reiss and Kröncke (2005). Strategic Environmental Assessment of the Mature Areas of the Offshore North Sea SEA 2: DTI (2001a). Dogger Bank SAC selection assessment document and draft conservation objectives and advice on operations: JNCC (2010a; 2011ab). Site survey data acquired for existing oil and gas installations in the region e.g., Cavendish (Fugro Survey Ltd 2003), Gordon (Fugro Survey Ltd 2003), Humphrey (Gardline Environmental 2006) and Monroe (Gardline Environmental 2003). 9.2.2 Existing Baseline 9.2.2.1 Regional Overview For the purposes of this assessment benthic communities comprise those species (excluding commercially exploitable shellfish and demersal fish) that live on (epifauna) or in (infauna) seabed sediment. In general terms, the type and distribution of the community is greatly influenced by sediment type and hydrodynamic conditions. CF00-00-EB-108-00001 Rev C1 Page 123 of 300

The structure of benthic communities varies temporally and spatially depending on a wide range of factors 1. There have been numerous studies of benthic communities in the North Sea 2 and from these it is generally acknowledged that physical boundaries separate distinct communities. In the North Sea, Glénmarec (1973) proposed three biogeographical provinces based on thermal stability of the water column over time. These provinces broadly relate to the NNS, CNS and SNS (DTI 2001a). Within each province a series of faunal communities can be distinguished inhabiting specific sediment types. Within the SNS four main benthic communities have been identified (DECC 2009d): Fine sands in 50-70m with a fauna typified by the polychaetes Ophelia borealis and Nephtys longosetosa. Muddy fine sands in 30-50m with the bivalve Nucula nitidosa, the shrimp Callianassa subterranea and the cumacean crustacean Eudorella truncatula. Coarse sediments mainly in less than 30m (1) with the polychaete Nephtys cirrosa, the sea urchin Echinocardium cordatum and the amphipod crustacean Urothoe poseidonis. Coarse sediments mainly in less than 30m (2) with the polychaetes Aonides paucibranchiata and Pisione remota and the amphipod crustacean Phoxocephalus holbolli. Benthic communities in the SNS are considered to be typified by a lower diversity than in the CNS and NNS, but with a higher biomass (DECC 2009d). The benthic ecology of the Dogger Bank differs from other regions of the North Sea due to a number of physical and biological factors and is considered a unique ecological region. The northern edge of the Bank forms the boundary between the CNS and the SNS community subdivisions. Overall benthic communities on the Dogger Bank have more and larger animals than those sandbanks further south (DECC 2009d). Variation in spatial distribution of species across the bank has been identified in some studies as caused by availability, quantity and quality of food in the benthic layer, which in turn is largely controlled by the Flamborough/Frisian frontal system to the north of the Bank (Wieking and Kröncke 2003). However, survey work conducted on behalf of the JNCC in 2008 has identified that shallow, intermediate and deep waters show different species assemblages. The shallower areas have low diversity consistent with disturbed habitat due to increased exposure to waves and wider ranges in sea temperatures. More diverse communities exist across the main extent of the Bank (JNCC 201; DECC 2011c). The survey found that the majority of stations within the csac site boundary had similar communities characterised by two amphipod species Bathyporeia elegans and Bathyporeia guilliamsoniana, the polychaete Magelona mirabilis and the burrowing bivalve Tellina fabula (formerly Fabulina fabula) (JNCC 2011a). In general, the benthic communities on the Dogger Bank are typical of fine sand and muddy sand sublittoral sediments with five distinct biotopes identified (Table 9-2). None of the biotopes are considered rare and are not listed as a designating feature of the csac, however the Dogger Bank has been designated for its sandbanks habitat and associated communities and all of these biotopes are characteristic of dynamic environments with moderate to high levels of disturbance from wave action and/or strong tidal streams (Connor et al. 2004). Communities in dynamic environments tend to have lower diversity and are dominated by species whose life histories favour recovery following disturbance. 1 Depth, sediment type, climate variability, hydrographic range, water temperature, supply of organic matter, 2 Künitzer et al. (1992), Calloway et al. (2002), Heriot-Watt University (2001), Jennings et al. (1999) and Dyer et al. (1983) as overviewed in a literature review undertaken by UKOOA (1999). Further, macro studies include those undertaken by: Jones (1950); and Glémarec (1973). Diesing et al. (2009) completed a survey of the Dogger Bank on behalf of JNCC, as referenced in JNCC (2010b) CF00-00-EB-108-00001 Rev C1 Page 124 of 300

Table 9-2 : Benthic biotopes typical of the Dogger Bank Biotope Typical species Remarks 1. Nephtys cirrosa and Bathyporeia spp. in intralittoral sand (SS.SSa.IFiSa.NcirBat) 2. Sparse fauna on highly mobile sublittoral shingle (cobbles and pebbles) (SS.SCS.ICS.SSh) 3. Echinocyamus pusillus, Ophelia borealis and Abra prismatica in circalittoral fine sand (SS.SSa.CFiSa.EpusOborApri) 4. Tellina fabula and Magelona mirabilis with venerid bivalves and amphipods in infralittoral compacted fine muddy sand (SS.SSa.IMuSa.FfabMag) 5. Amphiura filiformis, Mysella bidentata and Abra nitida in circalittoral sandy mud (SS.SMu.CSaMu.AfilMysAnit) As biotope. Also Pontocrates spp. (Amphipoda), Magelona mirabilis and Chaetozone setosa (Polychaeta). Various polychaete and bivalve spp. Occasional epibiota such as crabs Liocarcinus spp. and Pagurus spp. Anemones, hydroids and bryozoans during settled periods. As biotope. Also numerous other polychaete and bivalve spp. As biotope. Venerid bivalves including Chamelea gallina. Also Bathyporeia spp. (amphipod) and polychaetes Chaetozone setosa, Spiophanes bombyx and Nephtys spp. As biotope. Also various polychaete spp., Echinocardium cordatum (sea urchin), Nucula nitidosa (bivalve), Callianassa subterranea (decapod prawn) and Eudorella truncatula (cumacean) Well-sorted medium and fine sands. Sediments subject to physical disturbance from wave action and tidal streams. Relatively low faunal diversity. Identified by JNCC as located within the shallower regions in the southwest. Clean shingle and/or pebbles. Strongly affected by tidal streams and/or wave action. Faunally impoverished, composition may display great seasonal variation. Identified by JNCC with the presence of Glycera lapidum as a characteristic species. Circalittoral and offshore medium to fine sand. Medium to very fine sand with some silt. May be affected by moderate wave exposure and tidal streams. May experience transitions in community composition. Identified by JNCC in the central and eastern area of the Bank. Cohesive sandy mud. May be affected by moderate wave exposure. Brittlestar Amphiura filiformis superabundant. Source: Adapted from Connor et al. (2004) with additional information from JNCC (2011b). A large number of surveys have been undertaken by oil and gas operations on the Dogger Bank which can provide information to support the assessment of potential impacts of the Cygnus development. GDF SUEZ E&P UK undertook seven site and pipeline route surveys in addition to the latest data acquisition to inform exploration and appraisal drilling. Other Operators in the area have also made their survey data available to the industry. Table 9-3 presents a summary of the findings of these surveys. CF00-00-EB-108-00001 Rev C1 Page 125 of 300

Table 9-3 : Benthic communities recorded across the Dogger Bank Site Sediment type Benthic Community Reference Dogger Bank psac Sand and sandy gravel The survey covered the whole of the Dogger Bank csac, however the proposed Cygnus A and B locations are identified with characterising amphipod species Bathyporeia elegans and Bathyporeia guilliamsoniana, polychaete Magelona mirabilis and burrowing bivalve Tellina fabula Diesing et al. (2009) in JNCC (2011a) Cygnus A (20.3 m) Poorly sorted fine sand Typical of a moderately dynamic sandy substrate. Key species are Owenia fusiformis, Tellina fabula, Bathyporeia elegans and Nephtys cirrosa. UTEC Survey Ltd (2009b) Cygnus Exploration Well (19.7 m) Moderately sorted fine sand Pre-Drilling: Community consistent with clean fine sands comprising psammophilious (sand-loving) species. Diversity and abundance higher than average for fine sandy SNS sediments which may indicate that the area has not been subject to major disturbances i.e., trawling. Dominant species are Owenia fusiformis, Spiophanes bombyx, Tellina fabula. Gardline Environmental (2005) Post-Drilling: Dominated by Owenia fusiformis, but notable absence of Bathyporeia elegans present in surrounding sediments. Overall marginal reduction in abundance, richness and diversity since pre-drilling survey. UTEC Survey Ltd (2009b) 44/12a-C (24 m) Moderately well sorted fine sand Community typical of clean fine sandy sediments, dominated by Owenia fusiformis, Bathyporeia spp. and Tellina fabula. Nephtys spp. also present. Gardline Environmental (2008a) 44/12a-D (24 m) Poorly sorted fine sand Community heterogeneous and not unusual for region. Compared to previous data for the area substantially lower numbers of individuals and the community appears patchy in nature. It would appear that sediment particle size influences community structure at this site. Dominant species are Owenia fusiformis, Tellina fabula, Bathyporeia spp. and Polinices pulchellus. Gardline Environmental (2008b) 44/12a-E (20 m) Moderately well sorted fine sand Community typical of fine sandy sediments. Relatively uniform in terms of composition, but sparse containing few taxa and individuals. Population heavily dominated by Owenia fusiformis. Other species include: Bathyporeia elegans and Tellina fabula. Gardline Environmental (2008c) 44/12a- F (20 m) Moderately well sorted mainly fine sand Characteristic of clean, sandy sediments. Community non-uniform and relatively impoverished, but not atypical for the area. Non-uniform nature due to heterogeneous sediment composition. Bathyporeia elegans and Tellina fabula dominate fine sediments and Pisione remota, Polygordius, Protodorvillea kefersteini and Branchiostoma lanceolatum dominate coarse sediments. Gardline Environmental (2008d) Cygnus to McAdam export route Very well sorted fine sand Typical community for this area of the SNS, although rich and diverse for a moderately dynamic sandy substrate. Community was numerically dominated by polychaetes but also showed high crustacean species richness. Most abundant species were the suspension feeding polychaete Owenia fusiformis, the mollusc Tellina fabula, an amphipod Bathyporeia elegans, and the polychaete Nephtys cirrosa. UTEC Survey Ltd (2009b) Cavendish (18 m) Well sorted fine sand Characteristic of shallow, clean sand substrates of the wider SNS. Biotope: Nephtys cirrosa and Bathyporeia spp. in infralittoral sand (IGS.NcirBat) Fugro Survey Ltd (2003) Gordon (21 m) Well sorted fine sand Characteristic of shallow, clean sand substrates of the wider SNS. Biotope: Nephtys cirrosa and Bathyporeia spp. in infralittoral sand (IGS.NcirBat) Fugro Survey Ltd (2003) Humphrey (15.3 m) Moderately well sorted fine sand Species richness varies widely over the survey area but is relatively typical of fine sand, nutrient poor sediments. Community generally uniform comprising known psammophilious species. Typical for the area and sediment type. Gardline Environmental (2006) Monroe (15-34 m) Poorly to moderately sorted fine to coarse sand Fauna is of a density and species richness typical for clean sandy habitat. Biotope: Nephtys cirrosa and Bathyporeia spp. in infralittoral sand (IGS.NcirBat) Gardline Environmental (2003) Cygnus to Tyne Poorly to moderately well sorted fine sand Fauna is uniform and relatively sparse, indicative of fine sands. Taxonomically rich with a relatively low abundance of individuals. Dominant species are Owenia fusiformis, Bathyporeia elegan, Spiophanes bombyx and Tellina fabula. Gardline Environmental (2009a) Cygnus to Slightly Shifting communities along the pipeline route that are indicative of particle Gardline CF00-00-EB-108-00001 Rev C1 Page 126 of 300

Site Sediment type Benthic Community Reference D15 gravelly sand and gravelly sand size, water depth and sampling succession but communities were largely characteristic of North Sea sediments. Mostly dominated by polychaete annelids with Nephtys sp. Scoloplos armiger, Spiophanes bombyx, Megelona filiformis, Magelona johnstoni and Owenia fusiformis dominating. Environmental (2009b). 9.2.2.2 Cygnus A platform location A 9km 2 area was surveyed around the proposed Cygnus A platform location in 2011, within which seven benthic stations were selected. In addition, three stations sampled as part of the export pipeline route survey were also within this area. Three 0.1m 2 faunal samples were taken from each sample location with the exception of ENV1 where no acceptable samples were obtained. Still photographs were also captured. Analysis of survey data suggests a species rich, diverse and relatively even faunal community, similar to that recorded during other Dogger Bank surveys. There is a slight variability in the macrofaunal communities across the sample locations, with differences likely to be the result of differences in sediment type (Gardline Environmental 2011b). Sediments consisting of coarse sand and gravel were notably dominated by the polychaete Polygordius sp., known to occur in higher abundance in such sediment types. In total 99 taxa were recorded with 108 juveniles from 11 taxa present. As found in other surveys in the area, polychaete individuals dominated the samples being 93% of the total number of individuals. This was due to large populations of Polygordius sp. found at three stations. The species made up 84% of the total population from the survey. Relatively low numbers were found at the other stations and it is considered that this is due to the mean particle size of the sediments at these stations i.e., Polygordius sp were only identified in significant numbers in samples with more coarse sediments. At one station, located south west of the proposed Cygnus A site, Polygordius sp. accounted for only 68% of the population due to the presence of Owenia fusiformis. This species was largely absent from other samples and comparison surveys show similarly uneven distribution. The other stations, all with smaller average particle sizes (i.e., finer sediments), showed a lower presence of polychaetes although they still remained dominant in some areas. The proportion of molluscs (20-33%), arthropods (10-27%), echinoderms (2-21%) and other (Cnidaria, Platyhelminthes Nemertea, Phoronida and Chordata) (<5%) was relatively consistent across these stations. Table 9-4 presents the distribution of taxonomic groups. Table 9-4 : Individuals and taxa identified during Cygnus A survey Group Individuals Taxa Abundance Proportional Contribution (%) Abundance Proportional Contribution (%) Annelida (Polychaeta) 14,022 93 41 41 Arthropoda (Crustacea) 257 2 25 25 Mollusca 329 2 17 17 Echinodermata 115 1 8 8 Others 411 3 8 8 Total 15,134 100 99 100 Source: Gardline Environmental (2011b). One species was found at all stations; the polychaete Glycinda nordmanni, but no species was in all replicate samples. This is likely to be due to the variation in sediment type. Four of the ten most abundant species, including Glycinda nordmanni may be more abundant following smothering (Hiscock et al. 2005). This indicates there may have been a smothering event in the area, but is more likely to be as a result of the highly mobile nature of the Dogger Bank. CF00-00-EB-108-00001 Rev C1 Page 127 of 300

36 of the 99 taxa were recorded in single samples with 30 represented by a single individual. Single species made up between 20% and 61% of the total taxa observed at a station indicating patchiness in community distribution. This may also be a sign that there has been little pollution or disturbance stress in the area (Gardline Environmental 2011b). One station showed high concentrations of arsenic in sediments, but there appeared to be no discernible effect on the faunal community (Gardline Environmental 2011b). The Dogger Bank csac has been designated under the EC Habitats Directive Annex I as sandbanks which are slightly covered by seawater all the time. Sandbanks are considered in this classification to be in water up to 20m deep. As this is the case for the majority of Cygnus, it is considered that this development is within the designated feature. Sabellaria spinulosa was not recorded during the site survey and there was no evidence of any additional discrete EC Habitats Directive Annex I habitats or other protected species within the survey area. 9.2.2.3 Cygnus B platform location A 9km 2 area was surveyed around the proposed Cygnus B platform location in 2011, within which ten benthic stations were selected. As for Cygnus A, three macrofaunal samples were taken at each station as well as still photographs. The macrofauna was typical of the species rich and diverse Dogger Bank communities observed during other surveys, with most variability attributed to patchy distributions of polychaetes. Gravelly patches were dominated by the polychaetes Pisioni remota, Owenia fusiformis and Polygardia sp., whilst sandier sediments were dominated by the amphipod Bathyporeia elegans and the bivalve molluscs Tellina fabula and Donax vittatus (Gardline Environmental 2011c). 2,753 individuals from 102 taxa were identified at the ten stations. Of these, 172 of the individuals were juveniles from 15 taxa. As identified at the Cygnus A location, polychaetes were the most variable taxa ranging from 15% to 83% of individuals at stations. The high polychaete contribution to the total abundance was principally due to high numbers of three species: Pisioni remota; Polygardia sp.; and O. fusiformis. O. fusiformis was the most common polychaete, with 309 individuals found in twelve samples. As found at Cygnus A, the large proportions of polychaetes were found at sample locations with the coarser sediments (i.e., largest particle size). The variation in polychaete distribution was therefore attributed to the variable sediment type. The proportion of crustaceans and molluscs was also variable between stations and contributed 16% and 14% of the individuals identified respectively. Echinoderms and other (which included Nemertea and Branchiostoma lanceolatum) showed relatively small numbers of individuals. Table 9-5 presents the abundance of individuals and taxa. Table 9-5 : Individuals and taxa identified during Cygnus B survey Group Individuals Taxa Abundance Proportional Contribution (%) Abundance Proportional Contribution (%) Annelida (Polychaeta) 1701 62 41 40 Arthropoda (Crustacea) 427 16 27 26 Mollusca 397 14 22 22 Echinodermata 82 3 6 6 Others 146 5 6 6 Total 2753 100 102 100 Source: Gardline Environmental (2011c). At those stations where typical find sandy seabed was found, the dominant species were the amphipod crustacean Bathyporeia elegans and bivavle molluscs Tellina fabula and Donax vittatus. The gastropod Euspira pulchellus was less abundant but more widespread. CF00-00-EB-108-00001 Rev C1 Page 128 of 300

34 taxa were only present in one sample, of which 30 were represented by one individual. This is indicative of the absence of any notable contamination or disturbance as in these instances these species would be replaced by high abundances of more tolerant species. There was no evidence in the survey results to suggest that the faunal community had been adversely affected by any anthropogenic contamination. S. spinulosa was not identified and there was no evidence of any additional discrete EC Habitats Directive Annex I habitats other than the csac designating feature or other protected species within the survey area. 9.2.2.4 Export and Intra-field Pipeline Routes Twelve macrofaunal stations were selected along the export pipeline route with a further three along the intra-field pipeline route. As at Cygnus A and B still photographs and three samples were taken at each station. A reference station 200m from the route centreline was also acquired and two transects with only the camera system were undertaken. The majority of stations recorded a species rich, diverse and moderately even faunal community, with dominant species changing along the route with changes in water depth and sediment type. The deeper communities were characterised by the presence of brittlestars. Shallower, sandier communities on the Dogger Bank were dominated by a mixture of bivalves (e.g., Tellina fabula and Donax vittatus) and polychaetes (e.g., Magelona johnstoni and Owenia fusiformis). As observed at the Cygnus A site, areas of coarse sand and gravel were dominated by the polychaete Polygordius sp. In general, 32,061 individuals from 181 taxa were identified, of which 1% were juveniles. As observed at the Cygnus A site, areas of coarse sand and gravel were dominated by the polychaete Polygordius sp. Three stations in particular (one on the export pipeline route and the other on the intra-field pipeline) had very high numbers of individuals. The species accounted for 88% of the total individuals recorded at these stations. A third station had high numbers of three polychaete species: Polygordius sp; Mediomastis fragilis; and Scalibregma inflatum, which were also present at the Cygnus A site. At all sites coarse sand was thought to be the reason behind the difference in the community. O. fusiformis was found at one station on the export pipeline route, relatively close to the Cygnus A location, supporting the findings at the Cygnus A site that this species is unevenly distributed in the area. At the remaining stations polychaetes accounted for 36% of individuals with molluscs or echinoderms being more abundant. The brittle star A.filiformis was abundant at the deepest station which had gravelly muddy sand and suffered from the greatest disturbance. Table 9-6 presents the species abundance and proportional contribution. Table 9-6 : Individuals and taxa identified along the export and intra-field pipeline routes Group Individuals Taxa Abundance Proportional Contribution (%) Abundance Proportional Contribution (%) Annelida (Polychaeta) 30435 95 70 39 Arthropoda (Crustacea) 350 1 54 30 Mollusca 639 2 35 19 Echinodermata 327 1 12 7 Others 310 1 10 6 Total 32061 100 181 100 Source: Gardline Environmental (2011a). No taxa were found at all stations, however the mollusc Polinices pulcellus was present at all but two stations. This reflects the variation in sediment types along the routes as this species is able to live in a range of habitats. 56 taxa were recorded in single samples, of which 49 were represented by a single individual. The contribution of single individuals to the total number of taxa at stations ranged from 20-67% indicating variability and patchiness in the community. CF00-00-EB-108-00001 Rev C1 Page 129 of 300

Two camera transects were undertaken to investigate depressions close to the proposed intra-field pipeline route. One of the depressions revealed an anomalous seabed type which had the appearance of a possible relic biogenic reef feature. Sedimentary concretions or cohesive sediments which can be created by S. spinulosa were observed. However, surrounding sediments had been removed by scour. It would appear that this area may be conducive for S. Spinulosa, which is supported by the presence of other species that normally cohabit with S. Spinulosa including M.fragilis. However, there was no indication from sidescan sonar data, seabed imagery or seabed sampling of any Annex I habitats, such as biogenic reefs. S. spinulosa was not identified in any of the samples and there was no evidence of any additional discrete EC Habitats Directive Annex I habitats other than the csac designated feature or other protected species along the pipeline routes. 9.2.2.5 Tolerance to disturbance All species recorded within the field development area are either typical of Dogger Bank sandy communities or common to the SNS in general (Gardline Environmental 2011a,b,c). In terms of tolerances to anthropogenic disturbances as compiled by Hiscock et al. (2005), Owenia fusiformis is known to be intolerant to contamination from hydrocarbons while P. kefersteini is known to favour it. The tolerance to the most frequently observed taxa to heavy metals is unknown. Other key species, such as Bathyporeia elegans, Tellina fabula and Nephyts cirrosa, are intolerant of physical disturbances such as spud can placement. However, smothering by drill cuttings or rock material and increases in suspended sediments may favour species such as Tellina fibula and Owenia fusiformis (Gardline Environmental 2011c). 9.2.3 Potential Impact Identification This EIA has identified that during the project life cycle the activities listed in Table 9-7 have the potential to interact with benthic ecology. Table 9-7 : Benthic ecology - potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movement of transportation Installation of infrastructure Physical presence and movement of transportation Installation of infrastructure Drilling of wells Installation of infrastructure Drilling of wells Positioning structure on seabed e.g., jack-up legs, platforms, other subsea structures and anchors Use of thrusters in shallow water Trenching Concrete mattressing and rock material Discharge of cuttings Discharge of chemicals (including WBM) Discharge of reservoir hydrocarbons Physical damage to individuals. Habitat removal. Smothering. Potential toxic effects. Production Produced water Discharge of reservoir hydrocarbons Potential toxic effects. Maintenance of platform, pipelines and wells Discharge of chemicals CF00-00-EB-108-00001 Rev C1 Page 130 of 300

Project Activity Aspect Potential Impact Presence of platform Physical presence and movement of transportation Accidental Events Overboard loss of equipment or waste Spill of chemicals or hydrocarbons (<1 tonne) Spill of chemicals or hydrocarbons (>1 tonne) Discharge of sewage, grey water, food waste & drainage water Dropped objects Chemical, diesel or condensate spill Release of gas In general, the potential impacts identified above fall into two categories: Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Physical damage to individuals. Potential toxic effects. Impacts from chemical discharges, e.g., lethal (direct) toxicity and sublethal (indirect) effects Impacts resulting from physical disturbance e.g., smothering, damage to individuals or habitat loss The EIA concluded that there will be an interaction between the project activities and benthic ecology during the project, but that any resulting impacts will be restricted to the project area. Changes to the baseline may be noticeable (i.e., magnitude of medium) but the duration of any impact will be short-term (up to two years). The likelihood, spatial extent, magnitude, duration and significance of the impacts have been assessed in Section F of Appendices 2.1 2.4. 9.2.4 Mitigation Measures Measures outlined in Section 8.3.4 and 8.4.3 adopted to reduce and/or eliminate the toxic impacts of the development on water quality and the footprint of the development on the seabed will also mitigate the potential impacts on the benthic community. These are not repeated here but are listed in the previous sections and in Appendix 2. 9.2.5 Residual Impact Significance Assessment 9.2.5.1 Toxic effects from chemical discharges As previously described in Section 9.1.5, during construction chemicals will be discharged to sea either at the seabed from the well or pipeline, or at sea level from the drilling rig or construction vessels. All chemical discharges will be risk assessed and within DECC permitted levels as per the relevant Offshore Chemicals Regulations (OCR) chemical permit i.e., PON15B or PON15C. The majority of discharges at the seabed will be of products that are considered to be benign with the exception of small quantities of inhibition chemicals. Any toxic impacts on benthic communities will be extremely localised, restricted to the immediate area surrounding the discharge point and as such will not have a noticeable effect above individual level. Chemical discharges will be rapidly diluted and dispersed minimising the extent of any effects. As such, the impact of chemical discharges on benthic ecology has been assessed as having a low impact. 9.2.5.2 Physical disturbance The main impact of construction activities on benthic communities is from physical disturbance to the habitat either as a result of direct removal of the habitat or smothering of individuals and/or the habitat. The Cygnus development will disturb 1.46km 2 of seabed. Disturbance will be through a number of mechanisms: Use of DP thrusters in shallow water or use of anchors. Creation of drill cuttings piles immediately surrounding the well heads and the dispersion of cuttings material from the drilling rig. Positioning of structures on the seabed, such as the drilling rig, accommodation barge, platforms, and manifolds. CF00-00-EB-108-00001 Rev C1 Page 131 of 300

Pipeline installation e.g., trenching. Deposition of concrete mattresses and rock material for rig stabilisation and pipeline protection. In all instances the direct result will be mortality of flora and fauna within the impact footprint. As demonstrated in Section 9.2, the species identified in the area are typical of the SNS and Dogger Bank region, and no rare or protected species were identified in the environmental baseline surveys. Although the survey report identified that a number of species that commonly coexist with S. spinulosa, this species was not found to be present and therefore this is not an Annex I S. spinulosa habitat. The species present are generally tolerant of moderate disturbance and increased levels of suspended sediments as a consequence of the high level of wave action and the strong storm events they are subject to. This suggests that individuals not within the direct footprint of activities will be tolerant to increased levels of suspended sediments or low levels of smothering as a result of sediment deposition i.e., from drill cutting plumes or trenching. However, in general the most abundant species have a low to high intolerance to smothering and displacement, suggesting that species directly within the impact footprints of the activities will be killed. The impact from the majority of the activities will cease within a few days or at most months. For example: drill cuttings piles will have dispersed within weeks to a few months (Section 8.3.5); and material placed on the top of the Bank such as rock material or concrete mattresses is likely to be covered in sand within a few months. Once the activity has ceased species will be able to recolonise the area. The concept of recovery of biological resources is not easy to define as community composition can vary over time, even in areas that remain undisturbed. A key factor to be taken into consideration when determining whether a community is identical in species composition and population structure following cessation of impact, is whether the biodiversity would have remained stable over that period in the absence of disturbance. Furthermore, the rate of recovery depends on several factors, including: Levels of natural disturbance Coarseness of sediment Depth Type of benthic community that is disturbed The types of benthic communities that typically colonise sediments that are subject to natural disturbances by currents or wind have much faster recovery rates than those species inhabiting consolidated sediments in low energy environments. As previously mentioned, the benthos in the development area is typical of a moderately disturbed habitat subjected to strong current and storm wave action and consequently species that inhabit the area will tend to recover more quickly after disturbance. At present there is very little available information on the rate of recovery of biological resources following the installation of pipelines compared with the impacts from activities such as dredging and trawling. A desk-study commissioned by GDF SUEZ E&P UK in 2008 (Metoc plc 2008b) reviewed existing literature to determine what recovery times might be expected for sandy areas, such as those found in the vicinity of the project area. The report concluded that recovery times are likely to be in the region of three months to two years. This conclusion is supported by the survey data collected at the Cygnus exploration well site (UTEC Survey Ltd 2009b). Two years after operations had ceased it is only just evident that the site within 300m of the wellhead was still in a disturbed state i.e., the site had nearly fully recovered, with the community showing marginally lower abundance, richness and diversity indices compared to pre-impact levels and the adjacent area. The top five characterising species were typical of the surrounding area, with the only absence being that of Bathyporeia elegans which has a preference for sediments with little or no fines. The survey also showed that the wider community was previously disturbed prior to May/June 2008, possibly by a severe storm event and recolonisation of the area had occurred (UTEC Survey Ltd 2009b). In conclusion, although there will be a residual impact on benthic ecology from physical disturbance to the seabed, which will be noticeable when compared to the baseline, disturbance will be localised, short-term and with no lasting effect. Therefore the majority of activities that CF00-00-EB-108-00001 Rev C1 Page 132 of 300

cause physical disturbance have been classed as having a low impact, with the exception of concrete mattressing and rock material, as discussed below. The placement of concrete mattresses and rock material on the seabed will smother individuals in the immediate footprint. Sedentary species will be particularly vulnerable to burial as they are unable to avoid such disturbances. The post-drilling seabed clearance survey at the Cygnus exploration well suggested that material placed in the high energy environment on top of the Bank is likely to be covered with sand within three months (Section 8.4.4.2; Rudall Blanchard Associates 2008), following which the area can be recolonised. In the lower energy deeper waters towards the ETS pipeline, it is likely that the hard substrate will become covered in sand, but at a lower rate than on top of the Bank. The new area of hard substrate with limited sand cover may be beneficial in encouraging colonisation of species, but it may take longer to establish a community due to the limited larval supplies in the predominantly sandy surrounding areas. As it will take longer for a community to establish and when established it is likely to be different to the pre-impact community the residual impact has been assessed as medium i.e., medium to large change compared to the baseline. It should be noted that this impact will be restricted to a small area of seabed, when considering the extent of the sandy sediments in the deeper waters as a whole. 9.2.5.3 Accidental events: spill of hydrocarbon (>1 tonne) As described in Section 7, a spill of hydrocarbons is unlikely and a significant spill would only occur if there were an incident involving construction and production support vessels. Marine diesel will disperse naturally, evaporating quickly on release, and any components that settle to the seabed will be naturally biodegraded by microbes within one to two months. Oil will not pool on the seabed. Elevated concentrations of hydrocarbons may be noticeable in sediments close to the discharge point after a large spill, which in turn could be toxic to benthic species. However, given the low background concentrations of THC & PAHs in sediments in the project area (see Section 8.4.2) any change is unlikely to be sufficient to change the classification of sediments from unpolluted, and toxic effects on marine ecology are expected to be limited. If either of the gas pipelines were to rupture gas would be released into the water column. Minor components of the Cygnus gas are toxic to marine animals but they will be rapidly diluted and dispersed by currents minimising their toxic potential. Benthic species immediately over the breach will be vulnerable to physical disturbance and smothering as the gas escapes through the sediment. As discussed above the benthic community is typical of a moderately disturbed community and recovery after an impact of this kind is expected within three months to two years. As such the EIA concluded that should a >1 tonne hydrocarbon spill occur it would have a low residual impact on benthic ecology. 9.3 FISH AND SHELLFISH 9.3.1 Baseline Data Sources The main sources of data include: Marine Management Organisation (MMO) fisheries statistics: Data from 2007 2010 for International Council for the Exploration of the Sea (ICES) rectangles 37F2 and 38F2: MMO (2011). Fisheries sensitivity maps for British waters: Coull et al. (1998). Published reports on sandeel habitats and distributions: Holland et al. (2005); Engelhard et al. (2008). Published report on abundance and diversity of elasmobranchs: Daan et al. (2005). Overviews of North Sea fisheries: DTI (2001d). Offshore Energy Strategic Impact Assessment: DECC (2009d). Dogger Bank SAC Selection Assessment: JNCC (2011a). OSPAR Commission (2000). CF00-00-EB-108-00001 Rev C1 Page 133 of 300

9.3.2 Existing Baseline Approximately 230 species of fish inhabit the North Sea. In the shallow SNS and Eastern Channel, fish species diversity is low but increases westwards (OSPAR Commission 2000). Fisheries sensitivity maps (Coull et al. 1998) indicate that the SNS is an important spawning and nursery ground for a number of commercially exploitable species. Analysis of fisheries statistics (2007 2010) from the MMO provides a good indication of the type of species currently present in the project area. It should be noted that this does not provide a definitive guide to the fish and shellfish in the area, as this data is not collected to provide an account of the community structure of fish and shellfish. However, as many of the species found in the North Sea are commercially exploitable it does serve as a useful indicator. The North Sea has been divided into a number of rectangles by the International Council for the Exploration of the Sea (ICES), which are used to report fisheries statistics. The Cygnus development lies across two ICES rectangles, 37F2 and 38F2. The most commonly caught species in ICES rectangle 37F2 and 38F2 are given in Table 9-8. More than 60 commercially important species are caught within these ICES rectangles, with catch between 2007 and 2010 being dominated by plaice (Pleuronectes platessa). Turbot (Psetta maxima), lemon sole (Microstomus kitt), cod (Gadus morhua) and sole (Solea solea) are also important. Further analysis of the landings statistics for commercial species is given in Section 10. Table 9-8 : Commonly caught fish and shellfish Plaice Turbot Lemon sole Demersal Pelagic Crustaceans Molluscs Source: MMO (2011) Cod Sole Dabs Mackerel Horse Mackerel Garfish Crabs Nephrops (Norway lobster) Lobster Squid Whelks Cuttlefish CEFAS provide information on spawning grounds (the location where eggs are laid) and nursery areas (the location where juveniles are common) for fish-stocks in the region in the format of their fisheries sensitivity maps (Coull et al. 1998). The development is within or adjacent to the spawning grounds of six species and juveniles of at least three species are likely to be present at certain times of the year. The key sensitivity periods for commercial species (based on the level of spawning and nursery activity) is summarised in Table 9-9 and the location of spawning and nursery grounds are identified in Figure 9-3. Periods of spawning and nursery activity within the vicinity of the Cygnus development area are shaded in blue. May to August is identified as a period of very high sensitivity with the three prior months (February to April) acknowledged as periods of high sensitivity. Of the six species that spawn in the area all but mackerel and sprat are demersal spawners i.e., they lay their eggs on the seabed. These species are more at risk from activities that disturb the seabed. Mackerel, horse mackerel, plaice, sole, cod, sandeels and whiting are all listed as priority species (marine species classification) on the UK BAP list (UK BAP 2011). CF00-00-EB-108-00001 Rev C1 Page 134 of 300

Table 9-9 : Summary of spawning and nursery activity Species Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Spawning and nursery activity Nephrops Sprat Spawning Sandeel Plaice Sole Mackerel Nursery activity Whiting Source: Coull et al. (1998) Figure 9-1 : Sandeels Source: www.marlab.ac.uk Sandeels Research shows that sandeels are abundant in the Dogger Bank region. In the context of the North Sea it is probably one of the most important areas for sandeels. Historically they have supported a thriving fishery however, overfishing has led to a reduction in the population resulting in low breeding success in seabird colonies and reduction in predatory fish stocks (see Section 10.1.2). Typically, they are concentrated along the edge of the bank in water depths of approximately 20-30m (JNCC 2011a). Sandeels are known to display strong seasonal and diurnal activity patterns. They hibernate in generally coarse sand or fine gravel in autumn and winter, whilst in spring and summer they exhibit diurnal movements, burying themselves in the seafloor at night and feeding on plankton in the water column during the day (Engelhard et al. 2008). A study by Holland et al. (2005) showed that areas which contained a high proportion of medium and coarse sand (particle size 0.25 to 2.0mm) were preferred seabed habitats for sandeels. However, it was found that the fraction of silt was just as critical as the level of coarse and medium sand. A high percentage of the habitat was occupied by sandeels where the silt content was below 2%. Above 4% silt the occupancy and density of sandeels was extremely low. Therefore, an ideal habitat would be a combination of low silt concentrations (<4%) and high fractions of medium and coarse sand (Holland et al. 2005). Survey results from the project area indicate that seabed sediments around the Cygnus A platform location were slightly gravelly sand whereas along the pipeline routes composition varied from sand to sandy gravel (Gardline Environmental 2011a,b). The sediment is shown to comprise on average >80% sands with a low fine (silt) concentration (<3%). The survey indicates that some areas match the type of sediment that sandeels prefer as their burying (resting) sites. CF00-00-EB-108-00001 Rev C1 Page 135 of 300

Figure 9-2 : Herring Source: www.marlab.ac.uk Herring Historically the Dogger Bank was noted for herring spawning from August October (Coull et al. 1998). Whilst herring are a pelagic species, they spawn demersally and are therefore sensitive to activities that disturb the seabed. CEFAS have confirmed that based on egg surveys, herring appear to no longer spawn in the large area shown in Coull centred on 54 o 30' north and 3 o east. (pers comm. M. Boon 2003). This spawning ground would have coincided with the project area. Further consultation following the environmental baseline survey of the appraisal well confirmed that CEFAS considered the potential for herring spawning in this area to be low (GDF SUEZ E&P Ltd 2008a). The site survey identified two areas of gravel ripples that may potentially be suitable for herring spawning. These are scour depressions located within the intra-field pipeline route corridor and close to the proposed Cygnus A location. They were probably produced by marine flooding in the late Holocene transgression with subsequent erosion of the surrounding sands and silts exposing the underlying sediment. Herring are reported to prefer raised banks of well sorted gravel (Drapeau 1973) as spawning substrate. As the features are depressed in relation to the surrounding seabed and are surrounded by fine sands it is likely that the aeration of the sediment is not sufficient for optimal herring spawning. It is therefore not considered that herring spawning is likely to take place at these sites. Elasmobranchs The term elasmobranch encompasses sharks, rays and skates. Fourteen species have been recorded as common in the SNS and distribution maps indicate that seven of these species are likely to be found in the project area (Table 9-10). Table 9-10 : Elasmobranchs present in the SNS and project area Type of elasmobranch Present in SNS Present in project area Sharks Rays Skates Spurdog (or spiny dogfish)* Nursehound Tope* Starry ray Cuckoo ray Undulated ray* Blonde ray Common skate* Long-nosed skate Lesser spotted dogfish Smoothhound Thornback ray Spotted ray Common stingray Lesser spotted dogfish Starry ray Cuckoo ray Thornback ray Spotted ray * denotes species marked as priority species on the UK BAP list (UK BAP 2011). Source: After Daan et al. (2005) Spurdog* Tope* Spurdog (also known as the spiny dogfish) (Squalus acanthias) and tope (Galeorhinus galeus) are some of the most abundant sharks found in UK waters feeding on crustaceans, cephalopods and fish. Peak breading is in June and July (DECC 2009d). Thornback ray (Raja clavata) and cuckoo ray (Raja naevus) are the two most abundant species of ray present in UK waters (DECC 2009d). As the table above shows, several of these species are considered priority species on the UK BAP list, with tope and spurdog known to be present in the project area. Whilst they do not have individual species action plans, their inclusion on the list means that the UK Government will take actions to maintain their current range and abundance. CF00-00-EB-108-00001 Rev C1 Page 136 of 300

0 0' 2 0'E 0 0' 2 0'E 0 0' 2 0'E Environmental Statement Figure 9-3: Location of spawning and nursery grounds 55 0'N 55 0'N 55 0'N 55 0'N 55 0'N 55 0'N Legend Proposed project development Nephrops Spawning Cygnus A Hub Nephrops Nursery 54 0'N Flamborough Head 54 0'N 54 0'N Flamborough Head 54 0'N 54 0'N Flamborough Head 54 0'N Cygnus B NPAI Cygnus export pipeline ETS tie-in Median line Land Sprat Spawning Sandeel Spawning Sandeel Nursery Plaice Spawning Plaice Nursery Sole Spawning Sole Nursery Nephrops Sprat Sandeel Mackerel Spawning Mackerel Nursery 0 0' 0 0' 2 0'E 2 0'E 0 0' 0 0' 2 0'E 2 0'E 0 0' 0 0' 2 0'E 2 0'E Herring Spawning Herring Nursery Whiting Spawning Whiting Nursery 55 0'N 55 0'N Flamborough Head 54 0'N 54 0'N 55 0'N 55 0'N Flamborough Head Flamborough Head 54 0'N 54 0'N 54 0'N 54 0'N 55 0'N 55 0'N Plaice Sole Mackerel 0 0' 0 0' 2 0'E 2 0'E 0 0' 0 0' 2 0'E 2 0'E 0 0' 2 0'E NOT TO BE USED FOR NAVIGATION Date Tuesday, June 7, 2011 09:43:11 Projection ED 1950 UTM Zone 31N Spheroid International 1924 55 0'N 55 0'N 55 0'N 55 0'N Datum D European 1950 Data Source GEBCO, UKDEAL, CEFAS (2004), Coull et al. (1998) 54 0'N Flamborough Head 54 0'N 54 0'N Flamborough Head 54 0'N File Reference Checked J:\P951\Mxd\O_Cygnus_ES\.mxd Figure_9-3_location_of_spawning_and_nursery_grounds_v1 Produced By Reviewed By Patricia Adams Anna Farley Herring Whiting km 0 25 50 100 150 200 250 0 0' 2 0'E 0 0' 2 0'E Metoc Ltd, 2011. All rights reserved.

9.3.3 Potential Impact Identification This EIA has identified that during the project life cycle the activities listed in Table 9-11 have the potential to interact with fish and shellfish. Table 9-11 : Fish and shellfish potential impact identification Project Activity Aspect Potential Impact Construction Drilling of wells Installation of infrastructure Physical presence and movement of transportation Physical presence and movement of transportation Drilling of wells Installation of infrastructure Drilling of wells Subsea noise Discharge of sewage, grey water, food waste & drainage water Discharge of chemicals (including WBM) Discharge of reservoir hydrocarbons Species avoid spawning and nursery grounds. Physical damage to individuals. Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Potential toxic effects. Drilling of wells Discharge of cuttings Loss of spawning and nursery Installation of infrastructure Trenching Concrete mattressing and rock material (including rig stabilisation) ground affecting stock viability. Physical damage to individuals Physical presence and movement of transportation Positioning structure on seabed e.g., jack-up legs, platforms, other subsea structures, and anchors Production Produced water Presence of platform Maintenance of platform, pipelines and wells Accidental Events Spill of chemicals or hydrocarbons (<1 tonne) Spill of chemicals or hydrocarbons (>1 tonne) Overboard loss of equipment or waste Discharge of reservoir hydrocarbons Discharge of sewage, grey water, food waste & drainage water Discharge of chemicals Chemical or hydrocarbon spill Release of gas Dropped objects Smothering. Potential toxic effects. Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Potential acute or long-term toxic effects which may affect balance of food chain. Potential toxic effects, which may affect recruitment and stock viability. Smothering / fatality CF00-00-EB-108-00001 Rev C1 Page 138 of 300

The majority of activities have been assessed as possibly having an impact on fish communities. The spatial extent of impacts range from local, for the majority of construction activities, to widespread, for accidental events. The sensitivity will be low to medium with a short-term duration. The likelihood, spatial extent, duration, sensitivity, recoverability and significance of the impacts have been assessed in Section G of Appendices 2.1-2.4. 9.3.4 Mitigation Measures Potential impacts that require mitigation fall into two categories: those that could have toxic effects and those that have a physical impact on individuals, habitat and spawning /nursery grounds. Measures to mitigate deterioration in water quality and toxic effects of chemicals have previously been outlined in Section 8.3.4, whilst measures to minimise physical disturbance are discussed in Section 8.4.3. They have not been repeated in full here but are provided in Appendix 2. To reduce the impact of chemicals and waste on fish and shellfish, products that are environmentally benign will be preferentially selected for all project activities. All chemical discharges will undergo a risk assessment prior to discharge. Discharges of chemicals will not exceed values approved on the appropriate PON15 chemical permits. Chemical use and discharge will be minimised where operationally possible by measures such as recycling drilling muds. Waste storage procedures will be line with the garbage management plans and current legislation governing discharges to sea from vessels. The footprint of the construction activities will be minimised through careful project planning and design. For example, mattressing and rock protection will be the minimum required to ensure protection or stabilisation requirements are met and opportunities to reduce the number of rig moves are currently being explored. Management controls will be in place to reduce accidental events. The development and all activities will be covered by a site specific OPEP. Third party contractors will have their own procedures in place to mitigate accidents. These will be fully considered and harmonised with the GDF SUEZ E&P UK OPEP prior to operations commencing. 9.3.5 Residual Impact Significance Assessment 9.3.5.1 Subsea noise Defra and JNCC have identified that the Blocks in which drilling will be undertaken do not have any periods of concern for drilling or seismic activities. Blocks 44/16, 43/19, 43/20 and 43/24 have periods of concern for seismic surveys due to potential damage to juveniles and eggs between January and May. These blocks, other than 44/16, also have periods of concerns for drilling activities between January and May and between August and December. The pipeline will be installed between April and July 2013 and neither of these restricted activities will take place in these blocks. Although no seismic activities will be undertaken, the guidance and much of the available research considering subsea noise relates to seismic surveys. Smaller larval fish and eggs are unable to move aside from the disturbance and those within close proximity will be unavoidably damaged. As the water column refreshes and brings more juveniles and eggs into the vicinity a fresh sample may be damaged. However, studies on the impacts of seismic activity show that numbers affected are generally small, since serious injury occurs only if the eggs, larvae or fry are very close to the guns (Gausland 2003). The subsea noise created by piling has a lower impact than seismic activity and will be of a limited duration. It is therefore not expected that there will be any significant effects on stock viability or populations. General construction and pipe laying (excluding piling) is generally continuous noise that is below 180dB (see Section 9.6.5.1) and therefore will have less of an impact than piling and will not be considered further. In addition, it is unlikely that the activities will significantly affect adult fish. Research indicates that during seismic surveys in the open sea (which will have a greater impact than piling) fish generally demonstrate avoidance tendencies by swimming away from air guns. A study carried out using underwater TV cameras to monitor the behaviour of fish, in response to the discharging of an airgun, revealed that the fish displayed a brief, voluntary reaction and that the moment the stimulus ceased the fish resumed their activities, with their intended track apparently unaltered. The long-term, day to night movements of shoals were also uninterrupted by low-frequency pulses projected into their path (Gausland 2003). Therefore, although the piling may have a temporary affect on fish behaviour it is unlikely to have a significant impact on adult fish populations in the CF00-00-EB-108-00001 Rev C1 Page 139 of 300

area. Moreover, any mature fish in the vicinity are likely to show avoidance behaviour during the periods of piling activity. 9.3.5.2 Habitat disturbance No residual impacts on fish, shellfish and elasmobranchs were identified as a result of construction or production activities. As construction activities will disturb the seabed (1.46km 2 ) they have the potential to disturb the spawning grounds for demersal species such as plaice, sole and sandeels. Installation of the pipelines during April to July is one of the more sensitive periods of the year with higher numbers of species using the region for spawning than at other times. The pipeline laying will temporarily increase suspended sediments and cause habitat disturbance. However, as previously described, it is anticipated that the pipeline route will return to its previous condition within a minimal timeframe. In addition, the seabed will be disturbed by the deposition of drill cuttings and rock material and concrete mattresses for rig stabilisation, pipeline crossings and pipeline protection. Although disturbed by drill cuttings, the composition of sediments is unlikely to significantly change (some fining as a result of drilling related discharges may be noticeable at the drill sites) and the habitat should still be suitable for spawning once construction has ceased. The presence of rock material and mattresses will change the composition of the habitat, introducing harder surfaces, which may not be suitable for spawning. However, the area affected is extremely small (1.46km 2 ) in comparison to the wide areas used by fish for spawning and nursing. In conclusion, large areas of the North Sea are used as spawning and nursery grounds and it is not considered that a small disruption at the development site from construction activities will have an impact on stock viability or population levels. The EIA concluded that there will be no significant residual impacts 9.3.5.3 Accidental events: spill of hydrocarbons >1 tonne An accidental spill of chemicals, diesel or hydrocarbons greater than 1 tonne was assessed as having the potential to have a residual impact of low significance. The likelihood of such an event occurring has been assessed in Section 7.2 and is minimised through mitigation measures required by the governing legislation and supported by industry best practices. In fish life cycles the egg and juvenile stages are the most vulnerable to toxicity in the water column, as adult fish are highly mobile and generally able to avoid polluted areas. Fish and shellfish will be vulnerable to toxic effects from gas and condensate dissolved in the water column i.e., following a breach in the pipeline or loss of well control. Although, minor components of the Cygnus gas are toxic to marine animals, they will be rapidly diluted and dispersed by currents minimising their toxic potential. In general, lighter refined petroleum products such as diesel and condensate will also mix in the water column, with toxic consequences. However, they tend to evaporate quickly and do not persist long in the environment. Localised fatalities would occur in the immediate vicinity of the spill, but fish are likely to avoid the area if the situation persists, and any effects are unlikely to be felt on a population level. As discussed above, there are particular periods of the year when fish species are more sensitive e.g. during periods of high spawning activity, and a spill during a particular sensitive period could affect recruitment for that year. However, the spawning/nursery grounds span large areas of the North Sea which should mean that long-term changes to populations are negligible. A major spill has therefore been assessed as having the potential for an impact of low residual significance. CF00-00-EB-108-00001 Rev C1 Page 140 of 300

9.4 SEABIRDS 9.4.1 Baseline Data Sources The main sources of data include: Block specific seabird vulnerability tables for the UK: JNCC (1999). Reports on bird distributions: Skov et al. (1995); Stone et al. (1995). Offshore Energy SEA and technical report on Dogger Bank seabird survey: DECC (2009b, c). Special Protection Area Designations: JNCC (2010c,d). 9.4.2 Existing Baseline Birds are very mobile and for this reason accurate assessments of their temporal and spatial distribution are difficult to make, particularly at sea. There are a wide variety of seabirds that are either endemic or regular visitors to the offshore waters of the SNS. The seabird survey undertaken to inform the Offshore SEA for the Dogger Bank identified within the region of the Cygnus field development: fulmar (Fulmarus glacialis); cormorant (Phalacrocorax carbo); shag (Phalacrocorax aristotelis); gannet (Morus bassanus); six species of gull; and five species of tern, which all breed around the mainland North Sea coasts immediately adjacent to the SNS. In addition, auks (particularly guillemot [Uria aalge]), kittiwake (Rissa tridactyla) and razorbills (Alca torda), Manx shearwater (Puffinus puffinus), storm petrel (Hydrobates pelagicus) and skua (great [Stercorarius skua], pomerine [Stercorarius pomerinus] and arctic [Stercorarius parasiticus]) depend on the SNS for feeding purposes for at least part of the year (DECC 2009b; Skov et al. 1995, Stone et al. 1995). JNCC have used the European Seabirds at Sea database to undertake statistical analysis of at-sea distributions of birds in order to identify areas of high seabird concentrations. This will potentially be used to support designation of possible Special Protection Areas (pspa). The results are currently being analysed by JNCC (JNCC 2011c). Without the conclusions of this assessment, the Important Bird Areas (IBA) identified by Skov et al. (1995) have been considered to provide an indication of the significance of the area for seabirds. The IBA programme identified a network of sites, at a biographic scale, which are critical for the long-term viability of bird populations. Although the areas are not afforded any statutory protection, they do serve as a useful indication of which areas of UK waters are of particular importance to seabirds. The Cygnus development is located in IBA 7 (Flamborough Head and the Hills). The area is known to be important for: Figure 9-4 : Kittiwake in flight Source: www.rspb.org.uk Fulmars, guillemot, kittiwake and razorbill (throughout the year). Gannets between September and April. Lesser black-backed gulls (Larus fuscus) between March and June. Herring gull (Larus argentatus) between November and February. Great black-backed gull (Larus marinus) between August and February. CF00-00-EB-108-00001 Rev C1 Page 141 of 300

Puffins (Fratercula arctica) between October and March. The area covers the Dogger Bank which is an important source of prey species such as sandeels (see Section 9.3.2). It should be noted that along the coastline adjacent to the proposed Cygnus development, is the Flamborough Head and Bempton Cliffs SPA. Although the SPA is approximately 165km west of the project area, birds use the Dogger Bank region for feeding. The site has been designated due to: A population of 83,370 kittiwake pairs representing at least 2.6% of the Eastern Atlantic breeding population (JNCC 2011d) Seabird assemblages of international importance, supporting 305,784 individual seabirds during the breeding season, including puffin, razorbill, guillemot, herring gull, gannet and kittiwake. The most abundant species seen in the region during 2008 seabird survey included guillemot, kittiwake, fulmar and gannet. Guillemots were observed to be actively feeding in the area, whilst sightings of some other species (puffin and common gull) were noted to be juveniles (DECC 2009b). The UK Seabird Monitoring Programme (Eaton et al. 2010) has tracked changes in seabird populations since 1986. It has identified that whilst there are more breeding seabirds in the UK than at the commencement of the project, many populations have stabilised or are in decline. Declining species include kittiwakes, arctic skuas and herring gulls. Gannets and great skuas are increasing in number; by 73% and 46% respectively since 1986. The drivers of change have been identified as climate change impacting species further down the food chain, introduction of non-native mammalian predators and fisheries management which has had both positive and negative impacts. 9.4.2.1 UK BAP Species There are 59 species of birds which are listed on the UK BAP list of priority species (UKBAP 2011). Two of these priority species are found within the vicinity of the Cygnus development area: the arctic skua (Stercorarius parasiticus) and the herring gull (Larus argentatus subsp. argenteus). Both arctic skua and herring gull have species specific action plans assigned to them during Stage 2 of the review UK BAP review process (see Table 9-12). CF00-00-EB-108-00001 Rev C1 Page 142 of 300

Table 9-12 : Species specific action plans Action Action text Reporting category Arctic skua (Stercorarius parasiticus) 1 Maintain the North-east Atlantic food chain, through sustainable fishing and mitigating the effects of climate change. 2 Maintain optimal nesting conditions in important breeding colonies (e.g., managing grazing, disturbance and predation). 3 Ensure sufficiently frequent monitoring of core populations. 4 Establish network of seabird feeing Special Protection Areas (joint action). Herring gull (Larus argentatus subsp. argenteus) 1 Determine the causes of the breeding population decline in no-urban areas and relate to concurrent increase in urban areas. 2 Maintain the North-east Atlantic food chain, through sustainable fishing and mitigating the effects of climate change (joint action). 3 Review the status of the herring gull on the general license under the Wildlife and Countryside Act and the Wildlife (Northern Ireland) Order. 4 Identify the important wintering areas for the races argenteus and aregentatus. 5 Designate important sites for wintering birds where appropriate. 6 Review the importance of recent declines in light of long-term (i.e., >25 years) trends for the species. Sources: JNCC (2010c and d) 9.4.2.2 Seabird Vulnerability Wider landscape action Species-specific management action Species-specific monitoring/survey Species-specific legislative action (protection or site designation) Species-specific research Wider landscape action Legislative action (protection or site designation) Species-specific research Species-specific legislative action (protection or site designation) Species-specific research Seabirds are sensitive to changes in the quality of the marine environment, especially to changes in fish stocks (which could affect food sources) and to oil pollution. The JNCC produced indices in 1999 identifying the susceptibility of seabirds to surface pollutants, specifically hydrocarbons, when seabirds are at sea following breeding and undergoing moulting for all UK offshore waters (JNCC 1999). Using these indices seabird vulnerability within the Cygnus development area and surrounding area has been assessed and is presented in Table 9-13 and Figure 9-5. CF00-00-EB-108-00001 Rev C1 Page 143 of 300

Table 9-13: Seabird vulnerability in the vicinity of Blocks 44/11a and 44/12a Block Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec All 43/10 1* 1* 1* 1* 2 4 3 3 1* 1* 1* 3* 1 43/15 1* 1* 1* 1* 2 4 3 3 1* 1* 2 3 1 43/20 1* 1* 1* 1* 2 4 2 2 1* 1* 2* 1* 1 44/6 3 3 2 2 4 3 3 2 1* 1* 3 3 44/7 3 3 2 2 4 3 3 2 1* 1* 3 3 44/8 3 3 4 2 2 4 3 3 2 1* 1* 3 3 44/11 3 3 2 2 4 3 3 2 1 2 3 3 44/12 3 3 2 2 4 3 3 2 1 2 3 3 44/13 3 3 4 2 2 4 3 3 2 1 2 3 3 44/16 2 3 1 2 2 4 2 3 2 1 2 1 2 44/17 2 3 1 2 2 4 2 3 2 1 2 1 2 44/18 2 3 1 2 2 3 2 3 2 1* 1* 1* 2 Key 1 = Very High 2 = High 3 = Moderate 4 = Blank = No Data * = JNCC highlighted as period of concern for drilling Source: JNCC (1999, 2011e), DECC (2011e) Seabird vulnerability in the vicinity of Blocks 44/11a and 44/12a (within which Cygnus is situated) is very high in October, high in September and from November, April and May and moderate to low for the remainder of the year. JNCC (2011e) have highlighted some months as periods of concern for drilling activity. These are indicated by an asterix in the above table. 9.4.2.3 Light Emissions Birds that migrate during darkness can be affected by the presence of artificial lights in previously unlit areas. The birds are attracted to the light (phototaxis) or become disorientated by it. The potential cause of this disorientation is thought to be interference of specific wavelengths of light with the internal magnetic compass that birds use for navigation. The result can be that they circle the light source, using up energy, decreasing the likelihood of reaching the shoreline or reducing the potential for survival and reproduction (Poot et.al 2008). A study in the Dutch sector of the SNS calculated that up to 10% of the migrating bird population will be impacted by light emitted from the main deck of offshore installations (OSPAR 2007). It is on the basis of wavelength interference that work has been undertaken by operators within the SNS to determine if alternative coloured lighting could be used without disrupting the birds behaviour. Blue and green lights are within the appropriate spectrum and field tests using green lights were initially successful in the Dutch sector. However, safety concerns have been raised, particularly in relation to helideck operations. It is understood that research in this area is continuing. CF00-00-EB-108-00001 Rev C1 Page 144 of 300

0 0' 2 0'E 54 0'N 54 0'N 55 0'N 55 0'N Hornsea Mere SPA Humber Estuary SPA 0 0' 2 0'E Legend Proposed project development Cygnus A Hub Cygnus B NPAI Intrafield pipeline Cygnus export pipeline ETS tie-in UKCS Block Land Median Line Annual Seabird Vulnerability 1 - Very High 2 - High 3 - Moderate 4 - NOTE: Not to be used for navigation Environmental Statement Figure 9-5: Annual seabird vulnerability Date Wednesday, August 31, 2011 09:26:23 Projection UTM Zone 31N Spheroid Datum Data Source File Reference Checked International 1924 ED 50 GEBCO, JNCC, UK Deal J:\P951\Mxd\O_Cygnus_ES\Final_31Aug2011\ Figure_9-5_seabird_vulnerability.mxd Produced By Reviewed By 0 250 500 1,000 km Emma White Anna Farley Metoc Ltd, 2011. All rights reserved.

9.4.3 Potential Impact Identification The EIA identified that during the project life cycle the following project activities have the potential to interact with seabirds (Table 9-14). Table 9-14: Seabirds potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movement of transportation Drilling of wells Installation of infrastructure Physical presence and movement of transportation Installation of infrastructure Drilling of wells Installation of infrastructure Drilling of wells Physical presence and movement of transportation Production Presence of platforms Physical presence and movement of transportation Physical presence and movement of transportation Maintenance of platforms, pipelines and wells Produced water Accidental Events Spill of chemicals or hydrocarbons (<1 tonne) Spill of chemicals or hydrocarbons (>1 tonne) Noise Use of thrusters in shallow water Trenching Discharge of chemicals (including WBM) Discharge of reservoir hydrocarbons Discharge of sewage, grey water, food waste and drainage water Discharge of sewage, grey water, food waste and drainage water Emission of light Noise Discharge of chemicals Discharge of reservoir hydrocarbons Chemical, diesel or condensate spill Avoidance of territorial areas Increased suspended sediment loads and turbidity effecting feeding Potential toxic effects Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Disturbance of migratory routes and changes to behaviour Avoidance of territorial areas Potential toxic effects through bioaccumulation of chemicals in food chain. Smothering Potential toxic effects Potential toxic effects Smothering CF00-00-EB-108-00001 Rev C1 Page 146 of 300

The likelihood of activities affecting seabirds was either assessed as possible or unlikely for all activities. If impacts were to occur they would be site specific, low in magnitude with a short-term duration. The exception to this was the spill of hydrocarbons (>1 tonnes) which, although still unlikely to happen, may have an impact affecting the wider environment to a degree that a change may be noticeable (i.e., magnitude of medium). The likelihood, spatial extent, magnitude, duration and significance of the impacts are presented in Section H of Appendices 2.1 2.4. 9.4.4 Mitigation Measures General mitigation measures to minimise the toxic potential of chemicals and thus reduce exposure concentrations for seabirds will be in place, as discussed in detail in Section 8.3.4 and Section H of Appendices 2.1 2.4. GDF SUEZ E&P UK will continue to monitor progress of research undertaken by other operators within the SNS in to the potential impact of artificial light from platforms on the migration of birds during darkness. Consideration will also be given to the use of alternative lighting systems should research identify that this has a significant beneficial impact without causing a negative effect on safety or operations. Accidental spills of hydrocarbons present the largest potential impact on seabirds and as such the mitigation measures to prevent spills are discussed in more detail in this section. GDF SUEZ E&P UK considers three levels of mitigation for hydrocarbon spills. Prevention In light of the significant consequences of a major accidental discharge, all operational personnel, whether in the direct employ of GDF SUEZ E&P UK or contractors will be made aware of existing environmental protection procedures and the crucial importance of maintaining the integrity of the containment policy. The risk of a spill is tackled on a day-to-day basis by GDF SUEZ E&P UK employees and contractors following good practice codes, collision avoidance and fuel handling and transfer procedures. Every effort will be made to prevent such spills. It is noted that most spills occur during offshore fuel transfer operations (bunkering) and as such GDF SUEZ E&P UK are committed to the following measures: Fuel will be transferred between the vessels via hoses that will be equipped with a one way valve. Bunkering operations will be conducted during daylight hours and in good weather, where possible. If during winter this is not possible transfers will be assessed to identify potential risks and any risks mitigated to acceptable levels. A continuous watch will be maintained during offloading. All bunkering operations will be conducted in strict compliance to contractor s procedures. These procedures will be referenced in a combined GDF SUEZ E&P UK Management System Bridging Document, which will be circulated to all appropriate personnel. The management of bunkering operations will be discussed with the contractor s team prior to commencement of operations. Control During the construction phase, the contractors owning each of the various construction vessels being used will retain individual responsibility for spills and maintain approved shipboard oil pollution emergency plans (SOPEP). In line with the Merchant Shipping (Oil Pollution Preparedness and Response Convention) Regulations 1998, the response to hydrocarbon release during the drilling and production phases will be outlined in an OPEP and referenced in a combined GDF SUEZ E&P UK HSE Management System Bridging Document, which will be circulated to all appropriate personnel. The OPEPs will provide detailed hydrocarbon release and spill scenarios to enable the determination of appropriate offshore actions, and reporting and training requirements for mitigating accidental spillage throughout all phases of the development. The OPEPs will provide further detail on this assessment and, in addition, will include: Definition of the response actions, including the roles and responsibilities of offshore and onshore personnel. CF00-00-EB-108-00001 Rev C1 Page 147 of 300

Reporting requirements of incidents, both internally amongst the offshore team (including contractors), and externally to statutory bodies such as the DECC, Her Majesty s Coast Guard (HMCG) and the JNCC. Model-based methodologies for determining the volume and potential movement of slick based on the modelling. The scenarios identified for modelling were loss of well control and loss of containment from the drilling rig. Well control measures such as blow-out preventors will be in place both during drilling and production phases. GDF SUEZ E&P UK will enhance its capacity to respond and close out a well blow out through: Identification of an alternative location to drill relief wells. Designed trajectory of relief wells will intersect the well at the top of the reservoir. Availability of required equipment and services to drill a relief well within 48 hours notice. GDF SUEZ E&P UK is also a member of OSPRAG which will provide support in a well blow out event. Remediation Any spills (diesel, condensate or chemical), including sheens, will be reported to the statutory authorities using the PON1 system. For larger spills, a comprehensive range of back-up resources is available to GDF SUEZ E&P UK through oil spill providers e.g., OSR. This includes trained staff, aerial surveillance and dispersant spraying capabilities. The GDF SUEZ E&P UK strategy for spills in this region is to allow natural dispersion and to monitor the progress of this dispersion. In the unlikely event that a large diesel spill occurred in the vicinity of vulnerable populations of seabirds or marine mammals, advice would be sought from the DECC, the Defra and the JNCC as to whether dispersant spraying would be appropriate and would be approved. 9.4.5 Residual Impact Significance Assessment Mitigation measures taken during the construction and production phases have been assessed to be sufficient to reduce the impact on seabirds in the area. As such, none of these activities have been taken forward for residual impact significance assessment (see Appendix 2). There is not sufficient information publically available to inform an assessment of the potential impact of artificial light from the platforms on the migration of birds during darkness. For this reason, although the potential impact is acknowledged it has not been assessed in the EIA. 9.4.5.1 Accidental events: spill of hydrocarbons >1 tonne There is the potential that seabirds could be affected if a large spill of hydrocarbons (condensate, diesel or oil based chemicals) occurred. Cygnus is a gas reservoir and therefore a large spill with the potential to significant effect seabirds is expected to be extremely rare. Diesel and condensate will evaporate rapidly on release and will naturally disperse. Modelling presented in Section 7.3, indicates that if the drilling rig lost its entire inventory the corresponding condensate or diesel spill will naturally disperse within 8 hours. If well control is lost during drilling the condensate spill from a well blow out will evaporate within 2-3km. As the Cygnus field is a gas field these two scenarios have been identified as the worst case volumes of hydrocarbons offshore. Seabirds that spend the majority of the time on the sea surface are most vulnerable as their feathers can become contaminated with hydrocarbons, which in turn may be ingested. Seabird vulnerability to hydrocarbon pollution generally moderate for the year with peaks of high to very high vulnerability between April to May and September to November. Drilling activity is scheduled to occur throughout the year and may therefore overlap at some stage with the sensitive periods for seabirds identified by the JNCC. Should a spill occur during one of these sensitive periods an intervention response may be required to minimise the risk of smothering and species injury. Mitigation measures, in the form of: a site-specific OPEP; management controls to eliminate bunkering spills; and the absence of heavy hydrocarbons, should prevent any sizeable spills. Given the likelihood of an impact occurring is unlikely the EIA concluded that the residual impact on seabirds would be of low significance. CF00-00-EB-108-00001 Rev C1 Page 148 of 300

9.5 MARINE MAMMALS 9.5.1 Baseline Data Sources This section draws upon information given in the following sources of data: Cetacean population estimates and distribution: SCANS-II (2008). Atlas of cetacean distribution (Reid et al. 2003). SEA reports on marine mammals: DTI (2001c); DECC (2009b,d and2011c). 9.5.2 Existing Baseline The North Sea has a rich diversity of marine mammal species. The following summary is based on information from the SEA2 report on marine mammals, which covered the SNS region (DTI 2001c): Eight species of marine mammal regularly occur over large portions of the North Sea: harbour seal (Phoca vitulina), grey seal (Halichoerus grypus), harbour porpoise (Phocoena phocoena), bottlenose dolphin (Tursiops truncates), white-beaked dolphin (Lagenorhynchus albirostris), Atlantic white-sided dolphin (Lagenorhynchus acutus), killer whale (Orcinus orca) and minke whale (Balaenoptera acutorostrata). A further four species of cetacean are recorded fairly regularly: Risso s dolphin (Grampus griseus), common dolphin (Delphinus delphis), long-finned pilot whale (Globicephala melas) and sperm whale (Physeter macrocephalus). There have been occasional at-sea records of a further eleven cetacean species: humpback whale (Megaptera novaeangliae), blue whale (Balaenoptera musculus), fin whale (Balaenoptera physalus), sei whale (Balaenoptera borealis), Sowerby's beaked whale (Mesoplodon bidens), Cuvier's beaked whale (Ziphius cavirostris), pygmy sperm whale (Kogia breviceps), false killer whale (Pseudorca crassidens), northern bottlenose whale (Hyperoodon ampullatus), beluga whale (Delphinapterus leucas) and striped dolphin (Stenella coeruleoalba). At-sea records also indicate a further five pinniped species: bearded seal (Erignathus barbatus), ringed seal (Pusa hispida), harp seal (Pagophilus groenlandicus), hooded seal (Cystophora cristata) and walrus (Odobenus rosmarus). 9.5.2.1 Cetaceans Distribution of species in UK waters is dependent on their lifestyle characteristics. For example some species are more frequently found on the continental shelf or in areas of deep water (e.g., white-beaked dolphin), whilst others are more commonly found in inshore waters (e.g., bottlenose dolphin). Population estimates vary depending on species type as demonstrated in Table 9-15 below. Cetacean abundance in the SNS is relatively low compared to other north-western European waters and even the North Sea in general: relatively few species are observed, and typically in low abundance (Barne et al. 1995). The number of species of cetacean and the frequency of sightings (taken here as a measure of abundance) tends to decrease southwards through the North Sea (DECC 2009b). Our understanding of the distribution of cetaceans in UK waters is not complete and search effort has so far been insufficient to fully assess densities in many areas. However, the available sightings data (Table 9-15) suggest that five species of cetacean are likely to be present within and adjacent to the project area. The majority of cetacean sightings occur during the period May to September; however, this may reflect poor observation conditions outside this period (Reid et al. 2003, SCANS-II 2008). CF00-00-EB-108-00001 Rev C1 Page 149 of 300

Table 9-15 : Cetacean observations in the area of interest Species Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Bottlenose Dolphin Harbour Porpoise Minke Whale White-beaked Dolphin White-sided Dolphin Key Source: Reid et al. (2003) Likely to be present in SNS Likely to be present in Dogger Bank region Likely to be present in project area The most frequently occurring marine mammals in the project area are those primarily associated with relatively shallow continental seas. The EC Habitats Directive Annex II listed harbour porpoise is the most common of the UKCS cetaceans seen in the project area and both it and the whitebeaked dolphin are resident (DECC 2009d). Other cetaceans are seen less frequently in the area, with sightings occurring predominantly in the summer months. The minke whale is the most frequent visitor to the SNS among the larger whales (van dermeij and Camphuysen 2006). The Dogger Bank is considered to be the southernmost extent of its range within the North Sea (DECC 2009b). Figure 9-6 : Harbour Porpoise It is thought that the Dogger Bank region supports 2-5% of the North Sea harbour porpoise population for at least part of the year and it is a non-qualifying feature of the Dogger Bank csac (JNCC 2011). Harbour porpoise typically form pods of less than eight individuals but may, at times, form loose aggregations of 50 to several hundred animals (JNCC 2008). Source: Reid et al (2003) The white-beaked dolphin is also considered to be present in the project area, although the SCANS-II project indicated that sightings in the SNS are rare. They occur at a lower density than the harbour porpoise, but have similar school size, usually less than 10 individuals. However, pods of up to 50 are not uncommon and in northern parts of their range can comprise 100-500 animals (JNCC 2008). Figure 9-7 : Minke Whale The minke whale has a much smaller population but has been observed in the project area and adjacent waters. They are usually observed singly or in pairs, however when feeding can form aggregations of 10-15 individuals (Reid et al. 2003). Source: Reid et al (2003) White-sided dolphins and bottlenose dolphins have not been observed in the project area or adjacent waters but are found in the SNS and so may occur in the project area. White-sided dolphins prefer deeper waters and are observed in pods of tens to hundreds of individuals, sometimes up to 1,000 animals (DECC 2009d). Within these large aggregations, clusters of 2-15 animals can often be identified. Bottlenose dolphins commonly form pods of 2-25 animals, but occasionally number several tens or low hundreds, particularly in offshore deeper waters (JNCC 2008). CF00-00-EB-108-00001 Rev C1 Page 150 of 300

Table 9-16 presents abundance and density estimates for the five species identified as occurring in the project area. The conservation status of the species is also included. Under the EC Habitats Directive it is an offence to disturb a significant group of animals, which the JNCC considers to be 2% of the UK population. Table 9-16 : Cetacean population estimates and conservation status Species Natural Range (km 2 ) UK Population Estimate SNS & southern CNS Population Estimate 1 Density (animals/km 2 ) Species Favourable Conservation Status Significant Group (animals) Harbour porpoise Unknown 328,200 129,000 (39%) 0.46 Favourable 4,600 White-beaked dolphin Unknown 22,400 493 (2%) 0.0031 Favourable 450 Minke whale 759,000 16,400 4,700 (34%) 0.017 Favourable 330 White-sided dolphin Unknown 27,300 405 (1.5%) 0.0026 Unknown 100 Bottlenose dolphin 759,000 8,000 395 (5%) 0.0032 Favourable 160 Note 1: Percentage of UK population presented in brackets. Source: JNCC (2008), SCANS-II (2008), DECC (2009d), JNCC (2010e) 9.5.2.2 Pinnipeds Harbour (or common) seals and grey seals also frequently occur in the North Sea. The distribution of harbour seals at sea is limited by the need to return to land periodically. Until recently, data showed they were unlikely to be found more than 60km from the coast, although recent telemetry studies show a wider distribution across the North Sea (DTI 2001c) and long distance movements are possible; although these are usually to other haul-out sites (DECC 2009d). Maps indicate that in the SNS their distribution is predominantly along the coastline (DECC 2009d). Figure 9-8 : Grey Seal Grey seals have a wide distribution across the northwestern Atlantic, Baltic and north east Atlantic seas. UK populations are estimated to be approximately 130,000 individuals with a growth rate of 2.5% (DECC 2009d). Populations in the North Sea account for approximately 50% of the northeast Atlantic population (DTI 2001c). Grey seals are mainly distributed around and between haul-out sites and foraging areas and are more commonly seen in the CNS and NNS than in the SNS (DECC 2009d). Source: http://species.wikimedia.org/ Whilst traditional observation methods suggest that neither species will be seen in the offshore area, satellite telemetry studies have shown that both grey and harbour seals are occasionally present in the Dogger Bank area. Further research to obtain a more detailed assessment of the importance of the region for pinnipeds is being undertaken in the near future (JNCC 2011a). Both species have been listed as a non-qualifying feature of the Dogger Bank csac. 9.5.3 Potential Impact Identification The EIA identified that during the project life cycle the project activities identified in Table 9-17 have the potential to interact with marine mammals. CF00-00-EB-108-00001 Rev C1 Page 151 of 300

Table 9-17 : Marine mammal - potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movement of transportation Installation of infrastructure Drilling of wells Physical presence and movement of transportation Physical presence and movement of transportation Drilling of wells Installation of infrastructure Drilling of wells Production Presence of platforms Physical presence and movement of transportation Physical presence and movement of transportation Presence of platforms Produced water Maintenance of platforms, pipelines and wells Accidental Events Spill of chemicals or hydrocarbons (<1 tonne) Spill of chemicals or hydrocarbons (>1 tonne) Subsea noise Physical presence Use of thrusters in shallow water Discharge of sewage, grey water, food waste and drainage water Discharge of chemicals Discharge of reservoir hydrocarbons Discharge of sewage, grey water, food waste and drainage water Physical presence Subsea noise Discharge of reservoir hydrocarbons Discharge of chemicals Chemical, diesel or condensate spill Can cause physical injury or disturbance Increased risk of collision. Could cause physical injury Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Potential toxic effects. Potential toxic effects. Smothering. Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Increased risk of collision. Can cause physical injury or disturbance Smothering Potential toxic effects through bioaccumulation of chemicals in food chain. Potential toxic effects Smothering The likelihood of impacts occurring as a result of project activities ranges from possible to unlikely. In most cases the potential effects are limited in spatial extent to the project area, but a spill of hydrocarbons (>1 tonne) does have the potential to cause damage on a wider extent that is of low magnitude but medium-term duration. However, a large spill is extremely unlikely. The likelihood, spatial extent, magnitude, duration and significance of the impacts are presented in Section I of Appendices 2.1 2.4. CF00-00-EB-108-00001 Rev C1 Page 152 of 300

9.5.4 Mitigation Measures General mitigation measures to minimise the toxic potential of chemicals and thus reduce exposure concentrations for marine mammals will be in place, as discussed in detail in Section 8.3.4 and Appendix 2. Releases of hydrocarbons will be mitigated through a three stage process: prevention, control and remediation. This is discussed in detail in Section 9.4.3 and has not been repeated here. To mitigate potential nearfield impacts on marine mammals e.g., from subsea noise during piling, the Statutory nature conservation agency protocol for minimising the risk of injury to marine mammals from piling noise (JNCC 2010f) will be followed. Piling techniques will be confirmed during the final engineering design, however GDF SUEZ E&P UK will endeavour to comply with the requirements of indicative BAT during these operations. GDF SUEZ E&P UK are committed to the following measures: Piling vessel will have at least one experienced marine mammal observer (MMO) onboard and will have two if 24 hour operations are expected. Piling will not commence during periods of darkness or poor visibility (such as fog) unless MMOs are equipped with night vision binoculars. Passive Acoustic Monitoring (PAM) will be used if it is considered to be appropriate following consultation with JNCC. A pre-piling search will be conducted by the MMO. Piling will not commence if marine mammals detected within 500m of the activity or until 20 minutes after the last visual detection. Slow start up i.e., gradual ramping up of piling power, will be used for piling to ensure that any mammals outside the observation zone will have sufficient time to leave the area. The soft start up duration will not be less than 20 minutes. If a marine mammal comes within 500m of the piling during the soft start then, if possible, the piling will cease or at the least the power will not be ramped up further until the marine mammal has left the zone and there has been no further detection for at least 20 minutes. If there is a break in the piling operations for a period of greater than 10 minutes a pre-piling search and soft start procedure will be repeated. If deemed appropriate by the DECC, GDF SUEZ E&P UK will apply for a European Protected Species (EPS) licence. Activities will be undertaken in accordance with any conditions attached to the EPS licence. GDF SUEZ E&P UK will comply with the reporting requirements outlined in the JNCC protocol. Consultation with the JNCC determined that there are concerns about the use of ducted propellers and the possible impacts on pinnipeds. At the time of ES submission there was not sufficient information to determine whether this impact may occur during the Cygnus development. However, GDF SUEZ E&P UK are committed to avoiding the use of vessels with ducted propellers where possible and will consult with JNCC concerning mitigation measures should this not be considered feasible (see Section 9.5.5.2 below). 9.5.5 Residual Impact Significance Assessment 9.5.5.1 Subsea noise Cetaceans use sound to communicate, socially interact, and in some cases navigate using echolocation. Anthropogenic sources of noise therefore have the potential to interfere with their natural functions, and if the cetacean is within close proximity to loud noises, this can have the potential to cause physical injury. All cetacean species are designated as European Protected Species (EPS). It is an offence under the Conservation (Natural Habitats &c.) Regulations 1994 (as amended) (HR) and the Offshore Marine Conservation (Natural Habitats, &c.) Regulations 2007 (as amended in 2010) (OMR) to deliberately capture, injure, kill or disturb any wild animal of an EPS. Disturbance of animals, includes, in particular, any disturbance which is likely to: a) Impair their ability to: i. To survive, to breed or reproduce, or to rear or nurture their young; or CF00-00-EB-108-00001 Rev C1 Page 153 of 300

ii. In the case of animals of a hibernating or migratory species, to hibernate or migrate; or b) Affect significantly the local distribution or abundance of the species to which they belong. Guidance notes (JNCC 2010h) are available so that developers in the marine environment can better assess the likelihood of committing an offence, how offences can be avoided and if an EPS license is required. During construction and production, a range of activities will generate low levels of underwater noise consistent with a development of this size. These include: subsea installation, subsea monitoring and repair, vessel manoeuvring, conductor driving and drilling, and power generation (see Section 6.1.2.4). The majority of the noise sources are typical of construction and production activities and are generally below 180dB. However, it is possible that background subsea noise generated by construction vessels and drilling (excluding pile driving) may be audible to marine mammals up to 3km from the source of sound. Drilling activities produce a low-frequency continuous noise and studies have identified this to be similar to that of a large merchant vessel (DECC 2011b). Pipelay operations will also result in continuous noise; near field cumulative sound levels associated with previous developments have predicted the maximum sound level to be 177dB (DECC 2011b). As these noise sources are unlikely to cause damage or disturbance to marine mammals, they will therefore not be considered further. The major source of underwater noise will be from pile and conductor driving. Piles will be used to fix the Cygnus A and B platforms in place and to secure the manifold structures. The conductors used for the top section of the wells will have a diameter of 30" (0.76m), whilst the platform piles are 1.5m in diameter. Impact piling and conductor driving involves the instantaneous application of pressure to a solid structure and is characterised by short, impulsive noise events as the pile drive or hammer strikes the pile or conductor. Impact durations are typically between 50 and 100ms and intervals between impulses range from one to two seconds. Driving the conductor will take up to six hours. One conductor will be required per well therefore it is likely that up to four conductors will be driven per year. Installation of the 26 piles will take between two and six hours depending on the pile size. The piles for each structure will be driven within 24 or 36 hours. The source level noise from this type of piling is related to the diameter of the pile being driven. The diameter of the piles used for the platforms are larger than those required at the manifolds and greater than the diameter of the conductors. As such the following assessment has been based principally on the maximum size of the platform piles. Any impacts from the manifold and conductor piling are expected to be smaller than those from the platform piles. A noise exposure assessment has been carried out to ascertain whether injury and/or disturbance thresholds are likely to be exceeded. The JNCC (2010h) suggested risk assessment approach that has been followed is provided as Figures 6-1 and 6-2 in Appendix 6. Below is a summary of the risk assessment and the main conclusions. Noise levels There has been considerable recent research on noise impacts of piling for offshore windfarms, much of which is reported in the Offshore Energy SEA (DECC 2009b; DECC 2011b). Offshore windfarm piles are considerably larger than those planned for the Cygnus development (4-5m vs 1.5m diameter) but water depths are similar (20-30m). Thomsen et al. (2006) have investigated the potential impact of noise from piling by taking measurements at the FINO-1 research platform off Eastern Frisia, Germany. The platform was a jacket-pile construction with 1.5m diameter piles and construction was on a sandy seabed in water depths of approximately 30m. Pile driving was 60 beats per minute. ITAP (2005) measured third-octave-sound levels as peak sound pressure levels (SPLs) and sound exposure levels (SEL) at 400m from the source, resulting in the spectrum shown in Figure 9-9. These figures have been used in the noise exposure assessment as the construction of FINO-1 and the physical conditions at the site are comparable to those at Cygnus. CF00-00-EB-108-00001 Rev C1 Page 154 of 300

Figure 9-9 : Frequency spectrum of ramming pulses Notes: Red = dbo-p re 1 µpa, Blue = dbae re 1 µpa; Source: Thomsen et al. (2006) For the full field development 18 platform piles will be driven. Piling will be undertaken in April to May 2013 (Alpha WHP Installation), May 2013 (WYE Manifold Installation), May 2013 (SSIV Manifold Installation), April to May 2014 (Alpha QU Platform Installation), May to June 2014 (Alpha PU Platform Installation) and June 2014 (Bravo WHP Installation). Drilling and therefore conductor driving will be undertaken between May 2013 and September 2016. Could sound experienced exceed injury thresholds? Southall et al. (2007) proposed quantitative thresholds for levels of sound received by specific animals. For a multiple pulsed sound type, such as pile driving, it is estimated that a permanent shift in hearing thresholds, or PTS, will occur at a SEL of 198dB re 1 µpa2 -s weighted by auditory functional group or a received SPL of 230dB re 1 µpa (peak). Figure 9-9 illustrates that piling will generate a maximum SEL at 400m from source of 162 dbae re 1 µpa and a maximum SPL of 180dBo-p re 1 µpa. Both levels are below the thresholds for injury species. Indicating that at 400m from the sound source marine mammals will not be injured. Southall et al. (2007) categorised cetacean species into three functional hearing groups based on their auditory sensitivity: frequency (7Hz to 22kHz). Medium frequency (150Hz to 160kHz). High frequency (200Hz to 180kHz). When estimating the level of received sound to an animal, Southall et al. (2007) developed different weighting functions for each of the three functional auditory groups. These can be applied to the SEL. Placing a weighting on the SEL places lower importance on frequencies that are nearer the lower and upper ends of the species estimated hearing range. The weightings suggested by Southall et al. (2007) are presented in Appendix 6, Figure 6-3. Applying the weightings to the two peak frequencies experienced during piling: 120 and 310 Hz (see Figure 9-9), reduces the received levels to species potentially present within the project. As demonstrated in Table 9-18, the received SEL and SPL at 400m, at either frequency and for all species within the project area, is below the injury threshold values suggested by Southall et al. (2007). CF00-00-EB-108-00001 Rev C1 Page 155 of 300

Table 9-18 : Received levels at 400m by species Auditory Group Species Frequency (Hz) Weighting applied (db) SEL SPL Are Received (dbae re 1 µpa) Injury threshold (db re 1 µpa 2 -s) Received (dbo-p re 1 µpa) Injury threshold (db re 1µPa (peak) flat) received levels below injury threshold? Minke whale 120 0 162 180 Yes 198 230 310 0 159 179 Yes Medium High White-beaked dolphin White-sided dolphin Bottlenose dolphin Harbour porpoise 120-6 156 198 310-1 158 179 Yes 120-10 152 180 Yes 198 230 310-2 157 179 Yes In conclusion, following the injury risk assessment flow chart (Figure 6-1, Appendix 6), as the sound experienced at 400m does not exceed the injury thresholds, provided the mitigation measures are followed there is a negligible risk of an offence under the Habitats Regulations and Offshore Marine Conservation (Natural Habitats &c.) Regulations. Could sound experienced cause non-trivial disturbance? JNCC (2010h) state that for most cetacean populations in UK waters, disturbance, in terms of the HR and OMR, is unlikely to result from single, short-term operations e.g., the driving of a dozen small diameter piles or driving of conductors. Such activities would most likely result in temporary disturbance, which on its own would not impair the ability of an individual to survive, reproduce etc, nor result in significant effects on the local abundance or distribution. Marine mammals are observed to show direct behavioural responses to certain types of severe subsea noise disturbance such as pile driving, including moving away from an area for a period of time, diving behaviour changes (e.g., reduced surfacing times), vocalisation changes and separation of mothers and calves (JNCC 2010h). However, several authors have pointed out that the level of sound received does not seem to be the sole important aspect in determining the response and its significance (JNCC 2010h). Southall et al. (2007) describes several relevant studies published before 2007 that provide possible received levels at which cetaceans may demonstrate avoidance behaviour. These are summarised in Table 9-19. Table 9-19 : Received levels at which cetaceans demonstrate behavioural responses 180 230 Yes Auditory Group Received Level Range (db re 1 µpa) 140 to 160 Medium 90 to 120 High 90 to 120 Source: JNCC (2010h) Sound is attenuated as it propagates through the water and can be expressed as SPL = SL N log (R). In this equation SPL = sound pressure level, R is the distance from a source level (SL) and N is an attenuation constant associated with spreading. For shallow water N is in the range 20 to 25 (Nedwell et al. 2005) and for the purposes of this assessment N has been conservatively assumed to be 20. The above equation can be used to rebase the data for 400m to any distance from the source and therefore can estimate the zone within which cetaceans may be disturbed. This equation has been applied to the weighted SELs. Two frequencies were identified as having peak SEL values from Figure 9-9. When the weighting was applied to the SEL at these frequencies (see Table 9-20) in general the second peak (310Hz) had higher received sound levels. Therefore, the CF00-00-EB-108-00001 Rev C1 Page 156 of 300

weighted SELs for 310Hz have been used in the following assessment. Table 9-20 presents that SEL at distance from the piling activity for the three auditory function groups. Table 9-20 : SEL at distance from source Distance (m) Auditory Group Auditory Group Medium Auditory Group - High 1 214 210 209 100 212 208 207 400 162 158 157 500 122 118 117 1000-102 101 3000-90 89 4000-87 86 The calculations show that received sound levels will be below the threshold for disturbance at: 500m for low auditory group species e.g., minke whale 3km for medium and high auditory group species e.g., white-beaked dolphin, white-sided dolphin, bottlenose dolphin and harbour porpoise As sound will propagate through the water column spherically from the project site it is estimated that within an area of 28km 2, medium and high auditory species may exhibit behavioural disturbance. The SCANS-II project estimated cetacean densities in the southern CNS and SNS (see Table 9-16). Using these figures it has been estimated that 13 harbour porpoise may be disturbed by subsea noise. The calculations estimated that given the densities of other species in the region it was unlikely that other species would be disturbed. Although the calculations indicate that the disturbance thresholds proposed by Southall et al. (2007) are exceeded, it is repeated or sustained disruption of behaviours such as feeding or communication that is likely to have an effect on reproductive capacity and life expectancy. The piling activity will last less than 36 hours during each installation period and will not reoccur on subsequent days. The driving of the conductor will last for up to six hours and will only be completed up to four times per year. A reaction to this noise is not considered by Southall et al. to be particularly severe. In the JNCC (2010h) guidance, disturbance as described in the HR and OMR is interpreted as sustained or chronic disruption of behaviour. The EIA concluded that disturbance of behaviour for less than two days at a time was not considered sustained or chronic. Therefore following the risk assessment flow diagram (Figure 6-2) in Appendix 6 there is a negligible risk of offence and therefore, the residual impact on marine mammals has been assessed as low. 9.5.5.2 Collisions with vessels The presence of an increased number of vessels in the region as a consequence of construction and production activities has been identified as a potential cause for concern for marine mammals in the local area. A number of vessels (e.g., tugs, guard vessels and supply boats) will be used for a variety of activities (see Section 6.1.1.1). Whilst some vessels may be stationary during part of their deployment, an increased amount of vessel movement will be experienced throughout the region as vessels travel to and manoeuvre around the project area. The danger presented by vessel movements is that cetaceans may be killed or injured as a result of a ship strike. As mentioned above, under the EC Habitats Directive it is an offence to disturb marine mammals. In and adjacent to the development area, five species of cetacean and two species of pinniped may be present. Three of these species are non-qualifying features of the Dogger Bank csac (see Section 9.5.2). The use of MMOs will help to mitigate against the likelihood of collision with cetaceans during piling activities. Although MMO s will not be present on all construction vessels, the client representative onboard will liaise with the bridge and ensure that measures are in place should marine mammals be observed during construction activities. These will typically include recording sightings, monitoring the behaviour of the marine mammals to determine if the CF00-00-EB-108-00001 Rev C1 Page 157 of 300

construction activity will interact with their behaviour and potentially stopping the construction activity until the animal has left the area. With this in mind and the fact that the number of vessels is not expected to be considerably more than current levels in the area, it is considered that the residual impact will be of low significance as a change may only just be noticeable compared to the baseline. Recent reports have been made with regard to fatal injuries to pinnipeds. Thompson et al. (2010) report 15 instances of harbour and grey seals found in Eastern Scotland and 24 in North Norfolk between 2008 and 2010 all showing spiral lacerations consistent with being drawn head first through a ducted propeller. In all cases the injuries were fatal. The report concludes that very limited information about the circumstances of the deaths is available and the potential extent of the issue is not yet known. It is likely that the incidents identified have occurred close to shore and have all been in areas with high pinniped populations (e.g., St Andrews Bay and Blakeney Point). The significance of the deaths to UK seal populations currently remains unknown; systematic recording of such injuries did not commence until 2009 however there are records of this injury occurring from 1985 indicating it is unlikely to be a new problem (JNCC 2011f). The JNCC have indicated that if all pinnipeds found with these injuries in England were harbour seals, this represents around 0.85% of the populations at the Wash and North Norfolk Coast SAC. They consider that this is a low level of impact although they will not make any statement of judgement concerning the significance of this level of mortality until the 2010 population survey is complete (JNCC 2011f). Due to lack of available information on the circumstances of these injuries as well as on the current pinniped populations visiting the Dogger Bank (JNCC 2011a), it is not possible to determine the likelihood of this occurring during the project. The JNCC have recommended three possible mitigation measures that may be appropriate depending on the specific project: 1. Implementation of a timing restriction on use of such vessels during the period thought to be of key sensitivity (i.e., the pupping period). 2. The use of MMOs to maintain an exclusion zone and with the authority to request a delay to propeller / thrusters operation if seals were observed within this zone and to request shut-off if required and where possible. 3. Shoreline / stranding searches. During periods of pupping, pinnipeds will be restricted to the vicinity of haul-out sites and are unlikely to be found within the project area. It is therefore considered that measures 1 and 3 will not be applicable for this project due to its distance from the shore. GDF SUEZ E&P UK are committed to minimising the potential of causing injury to pinnipeds in this manner; during award of the contracts for any support vessels, DP vessels or self propelled barges, GDF SUEZ E&P UK will review the use of ducted propellers including Kort nozzles and Azimuth thrusters. Where possible vessels without these propellers will be preferentially selected, however if this is not feasible, GDF SUEZ E&P UK will consult with the JNCC concerning the use of MMOs. It is possible that the JNCC will further refine their advice concerning this issue and GDF SUEZ E&P UK will continue to consult with them in order to respond to any appropriate changes in best practice. 9.5.5.3 Accidental events: hydrocarbon spill >1 tonne There is the potential that marine mammals could be significantly affected if a large hydrocarbon spill was to occur. As discussed in Section 7.2, the likelihood of a large spill occurring is extremely rare. In addition, the Cygnus field is a gas field and no heavy crude oils will be present. Cetaceans have smooth hairless skins over a thick layer of insulating blubber, so hydrocarbons are unlikely to adhere persistently or cause breakdown in isolation. A diesel or condensate spill may cause eye or skin irritation or respiratory problems in marine mammals. However, in the offshore SNS environment and particularly on the high-energy Dogger Bank, any diesel or condensate spill will begin to dissipate immediately and should fully dissipate within hours (see Section 7.3.1). Therefore, the expected contact between marine mammals and any accidental spill is predicted to be minimal. Furthermore, marine mammal abundances are typically low in the SNS, although there are resident populations of harbour porpoise and white-beaked dolphins in the project area. Mitigation measures, in the form of a site specific OPEP and management procedures to reduce and control bunkering, should minimise any impact. If a spill were to occur, an intervention response may be required to minimise the risk of species injury. CF00-00-EB-108-00001 Rev C1 Page 158 of 300

For the reasons outlined above, the impact of accidental hydrocarbon spills on marine mammals has been assessed as of low significance. 9.6 PROTECTED SITES AND SPECIES 9.6.1 Baseline Data Sources The following data sources were drawn upon to inform the baseline description: Site specific survey data collected to inform the EIA: Gardline Environmental (2011a,b). Dogger Bank SAC selection assessment document and draft conservation objectives and advice on operations: JNCC (2010a; 2011a). UK BAP habitat action plan for sublittoral sands and gravels: UK BAP (2002). UK BAP and JNCC websites. 9.6.2 Existing Baseline There are a number of offshore protected areas (designated under both UK and International legislation) within 40km of the project area. All designated sites are illustrated on Figure 9-10. The features of each site are detailed below. EC Habitats Directive The EC Habitats Directive requires Member States to designate Special Areas of Conservation (SAC) for the protection of a number of habitats and species listed under Annex I and II of the Directive. The main aim of the EC Habitats Directive is to promote the maintenance of biodiversity by requiring Member States to take measures to maintain or restore natural habitats and wild species at a favourable conservation status (JNCC 2011b). Each Member State is required to propose a national list of sites for selection as a SAC. Currently in UK offshore waters there are: five offshore Sites of Community Importance (SCI) and five candidate SACs (csac). The Cygnus development lies within the Dogger Bank csac, 35km north of the southern boundary and 37km west of the eastern boundary, at the closest points (Figure 9-10); although the export pipeline route passes through the boundary. Dogger Bank csac The Dogger Bank has been selected under the EU Habitats Directive as a csac based on the following interest features: Sandbanks which are slightly covered by sea water all the time (qualifying). Harbour porpoise (Phocoena phocoena) (non-qualifying). Grey seal (Halichoerus grypus) (non-qualifying). Common seal (Phoca vitulina) (non-qualifying). The csac boundary encompasses 12,331km 2 of seabed, and includes the largest single continuous expanse of shallow sandbank in UK waters. In strict geological terms, the Dogger Bank is not a sandbank at all, but is a large shallow plateau which was formed by glacial processes before being submerged by sea level rise. A large part of the southern area of the bank is covered by water seldom deeper than 20m, the reason for its qualification as an Annex I habitat. It is also of international importance as it extends into German and Dutch waters, where it is designated as the German Dogger Bank SAC and Dutch Dogger Bank proposed SCI (Site of Community Importance) respectively. The Dogger Bank is considered to be a unique ecological region, unlike anywhere else in the North Sea. Its exposed location in open waters means it is subjected to substantial wave energy, which prevents the colonisation of the sand by vegetation on the top of the bank. The sediments range from fine sands with shell fragments on top of the bank to muddy sands at greater depths. The benthic community supported by these sediments is typified by polychaete worms, amphipods, small clams, hermit crabs, flatfish, starfish and brittlestars (see Section 9.2). Sandeels, which are an important prey source for fish, seabirds and cetaceans are present in the area, and the area is known as an important location for harbour porpoise, grey and common seals (JNCC 2011a). CF00-00-EB-108-00001 Rev C1 Page 159 of 300

Information describing the conservation value of the csac is available as part of the SAC selection assessment (JNCC 2011a) and draft conservation objectives and advice on operations (JNCC 2010a). Some of this information is summarised below: The Bank is vulnerable to both human (e.g., fishing, aggregate extraction, oil and gas activity, and wind farm construction) and natural activities (i.e., storm waves). Given current regulations in place to control oil and gas activity in and around the Bank and mechanisms available to modify fishing activity, the prospects of the Bank to maintain its structure in the future are good, provided that reasonable conservation efforts are made. A cessation of anthropogenic activity could allow natural recovery. The proposed boundary of the csac has been designed in order to enclose the minimum area necessary, which would ensure protection of the habitat, whilst allowing for mobile species and possible movement over time of the interest feature. The exact site boundary, as it currently stands, takes into consideration oceanographic processes, neighbouring conservation boundaries in Germany and the Netherlands, and the differing biological communities within the site. Despite the uncertainty about the boundary the feature is still graded as category A under the Global Assessment grade indicating excellent conservation value (Johnston et al. 2004). In 2010, JNCC gained government approval for the Dogger Bank dsac to proceed to consultation and the site was awarded psac status. On 26 th August 2011 Dogger Bank was redesignated as a csac following responses to the 2010 consultation. North Norfolk Sandbanks and Saturn Reef csac The Cygnus development is approximately 61km north of the North Norfolk Sandbank and Saturn Reef csac boundary (Figure 9-10). The North Norfolk Sandbanks and Saturn Reef is designated as a csac for the designating features: sandbanks which are slightly covered by seawater all the time ; and the presence of biogenic reefs (JNCC 2010g). The North Norfolk Sandbanks and Saturn Reef csac has an area of 3,603km 2 and are a series of ten main banks and associated smaller banks formed from tidal processes (Turnbull et al. 2005). Saturn Reef is a biogenic reef formed by ross worm S. spinulosa. Collectively, the sand banks form the most extensive example of offshore linear ridge sandbanks in UK waters, whilst also supporting communities typical of sandy sediments, and species such as polychaete worms, crabs and brittlestars. Saturn Reef consists of thousands of fragile sand-tubes to create a solid structure that rises from the seabed (JNCC 2010g). Further information regarding the designation of the area can be found in the SAC Selection Assessment document (JNCC 2010g). The proposed boundary for the North Norfolk Sandbanks and Saturn Reef csac has been designed in order to enclose the minimum area necessary in order to ensure protection of the habitat, whilst accounting for mobile activities and possible movement over time of the feature of interest. Cleaver Bank SCI The Cleaver Bank (Klaverbank in Dutch), in Dutch waters, has been identified as an area of ecological importance. Designated as a Natura 2000 site, it lies approximately 53km southeast of the Cygnus development. Covering 1,237km 2, the most distinctive feature of the site is that it largely consists of gravel and boulders, rather than sand, which have a representative red algal cover (Dotinga and Trouwborst 2009). The area is also important for seabird and harbour porpoise concentrations, and has the highest known zoobenthos in the Netherlands part of the North Sea. In addition, it supports deadman s finger coral (Alcyonium digitatum), lesser sandeel and is a spawning ground for herring (WWF-Netherlands 2008). Potential Annex I Habitat (PAIH) and Annex II species Of the 189 European habitats and 788 European species listed in Annexes I and II of the EC Habitats Directive, four habitats and eight species are known to occur in UK offshore waters. These are listed in Table 9-21. These four habitats have been identified by the European Commission as requiring additional SACs to be designated. The JNCC are currently working with the country conservation agencies to identify additional sites in waters away from the coast. CF00-00-EB-108-00001 Rev C1 Page 160 of 300

Table 9-21 : Annex I habitats and Annex II species Annex I Habitats Sandbanks which are slightly covered by seawater all the time Reefs (which include bedrock reefs, stony reefs and biogenic reefs Submarine structures made by leaking gas (pockmarks) Submerged or partially submerged sea caves (although sea-caves are not currently known to occur in UK offshore waters) Annex II Species Bottlenose dolphin Grey seal Common seal (Phoca vitulina) Allis shad (Alosa alosa) Sea lamprey (Petromyzon marinus) Allis shad (Alosa alosa) Twaite shad (Alosa fallax) It should be noted that habitats may occur outside these areas which qualify for designation. The Cygnus A and B platform sites and the first 40km of pipeline route either physically border or traverse an area listed under Annex I as sandbanks covered by water within the Dogger Bank csac. As discussed in Sections 8.4 and 9.2, the homogeneous fine sandy sediments in this area are typical of the top of the Bank supporting a benthic community that is sparse in terms of both taxa and individuals but is numerically dominated by polychaetes (a trait typical for North Sea sediments). The benthic species found are typical for a moderately disturbed habitat that has not been subject to recent or high levels of contaminant loading. No species of conservation importance designated under the EC Habitats Directive were observed in the area (Gardline Environmental 2011a,b). Of the Annex II species listed above, one species of cetacea and both species of pinniped may be found within the project area. None of the protected species have been recorded in the area but this does not mean that they may not be present. Their distribution and sensitivity to the project are discussed in detail in Section 9.4 above. CF00-00-EB-108-00001 Rev C1 Page 161 of 300

1 0'W 0 0' 1 0'E 2 0'E 3 0'E 55 0'N 55 30'N Dogger Bank csac Dutch Dogger Bank proposed SCI 54 30'N 54 30'N 55 0'N 54 0'N Flamborough Head Klaver Bank SCI 54 0'N 53 30'N Theddlethorpe North Norfolk Sandbanks and Saturn Reed csac 53 0'N 53 30'N 53 0'N 1 0'W 0 0' 1 0'E 2 0'E 3 0'E Legend Proposed project development Cygnus A Hub Cygnus B NPAI Cygnus export pipeline Intrafield pipeline ETS tie-in Protected Sites SAC SPA csac Dutch proposed SAC Potential Annex I Habitat / Net Gain Sandy sediments in <20m Net Gain Draft MCZ Environmental Statement Figure 9-10: Protected sites and habitats Date Wednesday, August 31, 2011 09:43:09 Projection UTM Zone 31N Spheroid Datum Data Source File Reference Checked International 1924 ED 50 GEBCO, JNCC, UK Deal J:\P951\Mxd\O_Cygnus_ES\Final_31Aug2011\ Figure_9-10_Protected_sites.mxd Produced By Reviewed By Emma White Anna Farley Median Line Land NOTE: Not to be used for navigation km 0 5 10 20 30 40 50 Metoc Ltd, 2011. All rights reserved.

EC Birds Directive The EC Birds Directive provides a framework for the conservation and management of, and human interactions with wild birds in Europe. It requires member states to establish Special Protection Areas (SPAs) for rare or vulnerable species. 271 SPAs have been established in the UK and 6 have been proposed and are considered potential SPAs. Of these sites, 107 have marine components, but only three are entirely marine. Carmarthen Bay was classified for its nonbreeding aggregations of common scoter. Outer Thames Estuary and Liverpool Bay were classified for their non-breeding aggregations of red-throated diver at both sites and common scoter at Liverpool Bay (JNCC 2011b). Work is currently underway by the JNCC and the four country nature conservation agencies 3 to identify further SPAs with marine components that will comprise a suite of entirely marine SPAs. Although there are no current plans to designate it as an a marine SPA, the Dogger Bank has been noted as being an important feeding area for the gannet (Johnston et al. 2002) and of international importance for at least seven species of seabird (Skov et al. 1995) (see Section 9.3). UK BAP As discussed in Section 2.1, 1150 species and 65 habitats are listed by the UK BAP as nationally and locally important. Species listed on the UK BAP that occur within the project area are discussed in the relevant Section of the ES (e.g., Sections 9.2, 9.3 and 9.4). Only one UK BAP habitat, sublittoral sands and gravels, has been identified as potentially occurring within the project area. Sublittoral sand and gravel is the most common habitat found around the coast of the UK. It occurs widely over large areas of inshore and offshore waters and is found in around the Cygnus platforms and along the Cygnus pipeline routes (see Section 8.4). The diversity of flora and fauna within the habitat varies according to the level of environmental stress to which they are exposed. For example, those exposed to strong tidal currents or wave action such as the conditions found on the Dogger Bank, have low diversity whilst those in deeper waters less exposed to natural disturbance are among the most diverse marine habitats. Factors listed in the action plan which could adversely affect the habitat include marine aggregate extraction and the use of bottom fishing gears such as beam trawls (UKBAP 2002). There is currently no legal protection for this type of habitat although there is provision to include areas within proposed SACs. Marine Conservation Zones (MCZ) The UK has signed up to international agreements that aim to establish an ecologically coherent network of Marine Protected Areas by 2012. The network will be a collection of areas that work together to provide more benefits than an individual area could on its own. The UK MPA network will be made up of several designations, including new Marine Conservation Zones (MCZs) European Marine Sites (e.g., SACs and SPAs), SSSIs and Ramsar Sites. The Net Gain MCZ project has identified potential MCZs in English waters from the Scottish border to Bawdsey. On the 31 st August 2011 the project put forward its final recommendation for 18 new MCZs to the Statutory Nature Conservation Bodies, which are proposed for a range of habitats and species. Should all Net Gain s recommended sites reach designation it would increase the total coverage of marine protected areas in southern and mid North Sea to approximately 30% of the area (www.netgainmcz.org). No Net Gain zones have been identified within 40km of the Cygnus development. The nearest areas are 67km south east and 70km west and will not be affected by the proposed development. 3 Council for Nature Conservation and the Countryside, the Countryside Council for Wales, Natural England and Scottish Natural Heritage CF00-00-EB-108-00001 Rev C1 Page 163 of 300

9.6.3 Potential Impact Identification The EIA identified that during the project life cycle the project activities and aspects listed in Table 9-22 have the potential to interact with protected sites or species. Table 9-22 : Protected sites and species - potential impact identification Construction Project Activity Aspect Potential Impact Physical presence and movement of transportation Drilling of wells Installation of infrastructure Physical presence and movement of transportation Subsea noise Use of thrusters in shallow water Can cause physical injury or disturbance to protected species Could affect integrity of protected site Could harm protected species Drilling of wells Discharge of cuttings Could affect integrity of Installation of infrastructure Trenching protected site Physical presence and movement of transportation Installation of infrastructure Physical presence and movement of transportation Drilling of wells Installation of infrastructure Drilling of wells Production Produced water Maintenance of platforms, pipelines and wells Physical presence and movement of transportation Physical presence and movement of transportation Presence of platforms Concrete mattressing and rock material (including rig stabilisation) Positioning structure on seabed e.g., jack-up legs, platforms, other subsea structures, and anchors Discharge of sewage, grey water, food waste and drainage water Discharge of chemicals Discharge of reservoir hydrocarbons Discharge of reservoir hydrocarbons Discharge of chemicals Discharge of sewage, grey water, food waste and drainage water Physical presence Subsea noise Potential toxic effects on protected species. Potential toxic effects through bioaccumulation of chemicals in food chain. Increased collision risk Can cause physical injury or disturbance to protected species Accidental Events Overboard loss of equipment or waste Spill of chemicals or hydrocarbons <1 tonne) Spill of chemicals or hydrocarbons >1 tonne) Dropped objects Chemical, diesel or condensate spill Could affect the integrity of protected feature Smothering Potential effects on the integrity of a protected site CF00-00-EB-108-00001 Rev C1 Page 164 of 300

These aspects all have the same potential impact in that they could lead to localised degradation in a protected site qualifying feature or an impact on a protected species. Whilst the project is within a csac, the baseline survey identified no rare or protected species. Possible impacts on the various interest features are described in more detail in the relevant chapter. The likelihood of the potential impacts occurring ranged from unlikely to definite depending on the activity. All impacts are likely to be restricted to either the project area or in the case of subsea noise to the local area surrounding the project. The EIA concluded that potential impacts were likely to be of low to medium magnitude and generally short-term, although a number of activities may have longerterm impacts e.g., the deposition of concrete mattresses and rock material. The likelihood, spatial extent, magnitude, duration and significance of the impacts have been assessed in Section J of Appendices 6.1 6.4. 9.6.4 Mitigation Measures The potential impacts on protected sites and species are the same as on the baseline physical and biological conditions of the project area, but with national or international consequences. As such, measures to actively mitigate impacts on protected sites and species are similar to those employed to mitigate impacts on the individual components of the environment which the designation protects. These are discussed in detail in relevant sections of this ES e.g., seabed conditions (Section 8.4.), water quality (Section 8.3), benthic ecology (Section 9.2), fish (Section 9.3), seabirds (Section 9.4) and marine mammals (Section 9.5). 9.6.5 Residual Impact Significance Assessment 9.6.5.1 Subsea noise Subsea noise was identified as having a residual impact on marine mammals, which are European protected species and listed on Annex II of the EC Habitats Directive. As discussed above, three species are listed as interest features of the Dogger Bank csac, and it is thought that there is a resident population of harbour porpoises in the area. The JNCC have assessed these marine mammals as having no known vulnerability to subsea noise, due to the lack of available information (JNCC 2008). However, the EIA concluded that there may be a potential for a residual impact of low significance on marine mammals as a result of subsea noise generated during piling and conductor driving. Full details of this assessment are provided in Section 9.5.5. 9.6.5.2 Physical disturbance of protected feature Under the EC Habitats Directive, the UK competent authorities for the Dogger Bank csac are charged with managing human activities within the site boundaries. This is done through ensuring that a number of conservation objectives are fulfilled. The JNCC have identified that the biological and physical structure of the Dogger Bank has been impacted locally by the small number of oil and gas installations present and that fishing is likely to have had an impact on community structure. It is noted however that with cessation of anthropogenic disturbances, natural recovery of the community would occur (JNCC 2011a). The current draft conservation objectives for the site (JNCC 2010a) require that proposed activities should not result in the deterioration or disturbance of the Annex I habitat sandbanks which are slightly covered by seawater all the time through any of the following: 1. Physical loss by removal (aggregate dredging) or obstruction (installation of petroleum and renewable energy infrastructure and cables); 2. Physical damage by physical disturbance or abrasion (demersal trawling); 3. Non-physical disturbance such as noise or visual presence 4. Toxic contamination by introduction of synthetic and/or non-synthetic compounds (pollution from oil and gas industry); 5. Non-toxic contamination by changes in nutrient loading (sewage from oil and gas rigs); 6. Biological disturbance by selective extraction of species (demersal trawling). Objectives 1, 3, 4 and 5 apply directly to the impacts of the proposed development, but objective 2 also needs to be considered in terms of the in-combination impact the proposed development and demersal trawling will have on the site. Construction activities will disturb 1.46km 2 of seabed. The csac encompasses 12,331km 2 of seabed. Of the seabed affected, 1.22km 2 will be within the csac; the construction footprint is therefore equivalent to 0.01% of the site. This is an extremely small percentage of the extent of the protected feature and it is unlikely to significantly affect extent and diversity representation of the communities present. In addition, the low faunal population, and lack of surface vegetation would CF00-00-EB-108-00001 Rev C1 Page 165 of 300

indicate that the benthic environment is of no particular sensitivity to physical disturbance (Gardline Environmental 2011a,b). No rare or protected species were identified in the baseline surveys (Gardline Environmental 2011a,b,c). Barite and bentonite (components of the drilling mud) have been widely shown to accumulate in sediments and may be present in noticeable levels for greater than ten years. However, as discussed in Section 8.4.2.4, post-drilling surveys at the Cygnus exploration well showed no significant elevation in concentrations of barium at the site (UTEC Survey Ltd 2009b). It therefore seems likely that the dynamic environment at the proposed development site is sufficient to widely disperse contaminants to concentrations undetectable above background levels. If accumulation is noticeable, the heavy and trace metals are generally of low toxicity to marine organisms and are unlikely to bioaccumulate. Therefore the contamination is unlikely to result in significant toxicity to benthic communities. It is estimated that a maximum of 44,300m 3 of sewage and grey water will be discharged to sea during construction with a further 436m 3 discharged to sea per annum during production (Section 6.1.3.3). This assumes that all the construction vessels will discharge sewage and grey water to sea. In practice, most construction vessels will be on site for a limited period and will retain waste onboard for disposal in port. Given the current speeds in the area, the small batch volumes of discharges, and the short duration of the majority of activities, the marine environment will be able to assimilate the discharges and biodegrade them through natural bacterial action. Any deterioration in water quality will be transient (limited to a few hours after the discharge) and will not have any residual impact on water quality and correspondingly the protected site or ecological communities it supports. The EIA has demonstrated that given: the highly dynamic nature of the sediments on top of the bank; and the fact that the benthic community is tolerant of a moderate degree of disturbance, communities physically disturbed will recover within two months to three years (Section 9.1 and 9.2). In addition, the high wave-induced sediment mobility is likely to infill scars left as a consequence of activities, and cover material placed on the seabed. Based on the above, the EIA concluded activities may cause short-term damage to the habitat which may be noticeable when compared to the baseline but that there will be no lasting effect on the integrity of the feature. As such it has been assessed as of low significance. 9.6.5.3 Accidental event: spill of hydrocarbons >1 tonne Oil spill modelling presented in Section 7.3 illustrates that for the worst case hydrocarbon spill scenarios identified for the Cygnus development, diesel and condensate will evaporate and naturally disperse rapidly and will not beach on any shoreline. Given the nature of the hydrocarbons present it is unlikely that the integrity of the Dogger Bank csac will be affected by a large spill. In addition, the mitigation measures outlined in the OPEP to minimise the impact of a spill once it has occurred and management controls to eliminate spills should prevent any sizeable spills. The EIA concluded that the significance of the residual impact would be low. As discussed above, there are a number of marine mammals likely to be found in the project area which are European Protected Species. Section 9.5.5 concluded that a large spill of hydrocarbons could potentially have a residual impact of low significance. CF00-00-EB-108-00001 Rev C1 Page 166 of 300

10.0 IMPACTS ON HUMAN ENVIRONMENT This section describes the existing baseline human environment, the impacts the Cygnus development project will potentially have on this environment, and how impacts, if any, will be mitigated. The section also qualifies the significance of any residual impacts. It follows the methodology set-out in Section 4. The human environment has been divided up into the following main areas: Commercial fishing (Section 10.1) Shipping and navigation (Section 10.2) Other marine users (Section 10.3) Archaeology (Section 10.4) 10.1 COMMERCIAL FISHING 10.1.1 Baseline Data Sources This section has made use of the following data sources: MMO fisheries statistics from 2002 2010 for ICES rectangles 37F1, 37F2, 38F1, 38F2, 39F1 and 39F2: MMO (2011). Published reports on sandeel habitats and distributions: Holland et al. (2005) and Engelhard et al. (2008). Overviews of North Sea fisheries: DTI (2001d); OSPAR Commission (2000). UK Offshore Energy Strategic Environmental Assessments 1 and 2: DECC (2009b and 2011b). Shipping intensity study undertaken for the Cygnus field development: Anatec (2011). 10.1.2 Existing Baseline The North Sea is home to approximately 230 species of fish, thirteen of which are the main targets for commercial (for direct human consumption) and industrial fisheries (where the catch is converted into fish meal and oil) (OSPAR Commission 2000). In the SNS, a number of different commercial fisheries operate, using a variety of fishing techniques (DECC 2009b). These include: Mixed demersal fisheries for cod, haddock and whiting using largely beam trawlers but also seine net, gillnet, trammel net, long-line and hand-line vessels. Mixed flatfish fisheries for plaice and sole which use trawl, seine net, trammel net, tangle net and long-line vessels. Herring and mackerel fisheries which use gillnet, pelagic trawl and hand-line vessels. Crustacean fisheries (particularly for the Norway lobster in the SNS) which utilise a range of gears including beam trawls, tangle nets, pots and demersal otter trawls. With regards to industrial catch, historically, sandeels have also been an important fishery in the SNS. The Dogger Bank alone provided between 26 and 62% of the entire North Sea sandeel catch during 2000 and 2006 (Engelhard et al. 2008). However, shortages in sandeels have been attributed to the fishing industry and in turn linked to low breeding success in seabird colonies, and reduced stocks of predatory fish species which are often commercially important themselves (DECC 2011b). As such, fisheries management measures are sometimes used to help stocks recover. An assessment of the fishing industry in the region of the development has been derived from MMO UK statistics. Statistics detailing fishing effort (in days fished) and species landed (live weight in tonnes and value in pounds ( )) have been obtained for the ICES rectangles in which the Cygnus development falls and for the surrounding rectangles for the period 2002 to 2010. The data considers UK vessels using both UK and foreign ports and foreign vessels landing at UK ports, but does not take into account foreign vessels landing at foreign ports. CF00-00-EB-108-00001 Rev C1 Page 167 of 300

The development is located within ICES rectangle 38F2. Between 2002 and 2010, 10 million tonnes of fish and shellfish were caught from the area. The most important fisheries within this rectangle are: Demersal species (e.g., plaice, dabs, cod and lemon sole): representing 99.1% of the total catch. Crustaceans (e.g., Nephrops and crabs): 0.86% of the total catch. Pelagic species (e.g., mackerel and horse mackerel): 0.04% of the total catch. Table 10-1 : Annual landings and value from ICES rectangle 38F2 (2002-2010) Row Labels Landings (tonnes) Value ( ) /tonne 2002 278 360,681 1,296 2003 756 1,239,646 1,640 2004 1,261 1,730,657 1,373 2005 901 1,486,454 1,651 2006 270 406,613 1,507 2007 669 957,333 1,431 2008 622 728,959 1,172 2009 1,413 1,514,052 1,072 2010 1,484 2,115,827 1,426 Total 7,654 10,540,222 12,568 Average 850 1,171,136 1,396 Source: MMO (2011) By far the most commonly caught species over the period analysed was plaice, with an average annual value of around 700,000 (see Table 10-2). The average annual commercial value of the total catch within the 38F2 rectangle was 1.7 million. The majority of the catch is landed in Harlingen (Netherlands), Urk (Netherlands), Scarborough (UK) and Grimsby (UK). Most fishing activity takes place during the summer months (Figure 10-1). Table 10-2 : Value ( ) of 5 most important species for the Cygnus development area and surrounding region (2002-2010) ICES Rectangle Plaice Turbot Sole Lemon sole Dabs 37F1 4,235,722 576,277 1,998,921 462,840 108,296 37F2 6,768,592 1,076,042 1,517,892 341,907 145,292 38F1 2,391,255 95,755 106,254 193,926 32,646 38F2 6,206,070 802,804 465,160 399,695 166,778 39F1 609,376 70,827 23,460 179,974 24,467 39F2 5,136,856 449,411 203,869 682,569 191,724 Grand total (2002 2010) from all rectangles Catch from 38F2 as a percentage of total species specific catch from the area 25,347,87 1 3,071,116 4,315,556 2,260,911 669,203 24 % 26 % 11 % 18 % 25 % Average annual value from 38F2 689,563 89,200 51,684 44,411 18,531 Source: MMO (2011) CF00-00-EB-108-00001 Rev C1 Page 168 of 300

Figure 10-1 : Seasonal variation in fishing activity Value ( ) 1,800,000 1,600,000 1,400,000 1,200,000 1,000,000 800,000 600,000 400,000 200,000 0 Jan Feb Mar Apr May Jun Jul Aug Sept Oct Nov Dec Month Source: MMO (2011) The overall value of the different species by area (financial yield per ICES rectangle) is an indication of the differential worth of areas and is a way of expressing sensitivity. This area has a relative value of low for pelagic and moderate to high for demersal and shellfish fisheries and an overall moderate relative value for all commercial species (Coull et al. 1998; MMO 2011). Fishing effort and catch per unit effort (CPUE) are moderate relative to the surrounding area (see Figure 10-2). For ICES rectangle 38F2 the CPUE is relatively high (0.5-1 tonnes/day) however, neighbouring rectangles (37F1 and 37F2), CPUE is higher at over 1.5 tonnes/day. Demersal fishery landing densities within the development area have been identified on the Maritime Data website as moderate. As such, this area has been classified as an important area for demersal fisheries but not as important as other areas to the north of the development (see Figure 10-2). CF00-00-EB-108-00001 Rev C1 Page 169 of 300

Average Annual Catch (2002-2010) 0 0' 2 0'E Average Annual Value of Catch (2002-2010) 0 0' 2 0'E Environmental Statement Figure 10-2: Summary of Cygnus area landings and effort data Dogger Bank dsac Proposed project development Cygnus A Hub Cygnus B NPAI 55 0'N 55 0'N 55 0'N 55 0'N Legend ETS tie-in Cygnus export pipeline Median Line Catch Average landings (tonnes) Land 0-600 54 0'N Flamborough Head Murdoch 54 0'N 54 0'N Flamborough Head Murdoch 54 0'N 600-800 800-1,000 1,000+ Theddlethorpe Theddlethorpe Value Average value ( ) 0-1,000,000 1,000,000-2,000,000 0 0' 2 0'E 0 0' 2 0'E 2,000,000-3,000,000 3,000,000+ Average Annual Fishing Effort (2002-2010) Average Annual Catch per Unit Effort (CPUE) (2002-2010) 0 0' 2 0'E 0 0' 2 0'E Effort Average days fished 0-100 100-150 150-200 200+ 55 0'N 55 0'N 55 0'N 55 0'N Catch per unit effort Live weight in tonnes per day 0-0.5 NOTE: Not to be used for navigation Date Tuesday, June 21, 2011 16:09:22 0.5-1 1-1.50 1.50+ Projection Spheroid ED 1950 UTM Zone 31N International 1924 54 0'N Flamborough Head Murdoch 54 0'N 54 0'N Flamborough Head Murdoch 54 0'N Datum Data Source File Reference D European 1950 JNCC, UKDeal, MMO J:\P951\Mxd\O_Cygnus_ES\.mxd Figure 10-2 Fisheries landings statistics and effort Theddlethorpe Theddlethorpe Checked Produced By Reviewed By David Cook Anna Farley 0 0' 2 0'E 0 0' 2 0'E Kilometres 0 20 40 80 120 Metoc Ltd, 2011. All rights reserved.

An assessment of fishing activity in the Cygnus development area has been reviewed as part of the Anatec (2011) shipping study. Fishing data has been collected within 2nm of the Cygnus platform sites and proposed pipeline route. The area with the most sightings is along the export pipeline in the shallower waters, with density gradually decreasing as the pipeline moves into deeper waters (see Figure 10-3). Here fishing in the surrounding area is low due to the presence of the existing Trent platform. Figure 10-3: Fishing density Source: Anatec 2011 Figure 10-4 shows the recorded individual fishing vessels colour coded by nationality. The majority of fishing vessels within 2nm of the proposed pipeline route were Denmark and UK registered vessels which accounted for 66% and 21% respectively. The registered nationalities of the remaining fishing vessels were Germany (5%), the Netherlands (3%), Others (3%), France (1%), Norway and Belgium (both less than 1%). Figure 10-4: Fishing vessels within 2nm of Cygnus by Nationality Source: Anatec 2011 CF00-00-EB-108-00001 Rev C1 Page 171 of 300

Figure 10-5 shows fishing vessels by type within 2nm of the Cygnus pipeline route. 85% of the vessels are unspecified with the remaining 15% specified. The specified vessels can be broken down into the following identified vessel types: beam trawlers (43%), trawlers (32%), bottom seiners (24%) and a single sighting of a demersal trawler. Figure 10-5: Fishing vessels by type Source: Anatec 2011 The main concern with fishing in the area is the potential for fishing gear to collide with the pipeline causing damage to it, and, or, causing the fishing gear to become entangled. The vessels which pose the greatest threat are beam trawlers and demersal trawlers due to the gear they tow. Beam trawlers tow a beam attached to a heavily weighted net along the sea bed and demersal trawlers similarly tow a net along the seabed whilst being kept open by boards, floats and weights. As discussed above 43% of the specified vessel types in the area are beam trawlers, which correspond to 6.5% of all the vessels in the area. These vessels were recorded all along the pipeline route, although the majority, as with the single sighting of demersal trawler, were observed in the deeper waters near the Trent platform. The area along the pipeline route which is most vulnerable to trawling hazards is on the south-west patch of Dogger Bank close to the 20m contour. CF00-00-EB-108-00001 Rev C1 Page 172 of 300

10.1.3 Potential Impact Identification The EIA identified that during the project life-cycle the activities identified in Table 10-3 have the potential to interact with commercial fishing. Table 10-3 : Commercial fishing - potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movements of vessels Exclusion zones Anchoring Exclusion from fishing grounds Increased collision risk. Persistent anchor piles could snag fishing gear Drilling of wells Discharge of cuttings Persistent drill cuttings piles could snag fishing gear Installation of infrastructure Installation of infrastructure Production Presence of platform Physical presence and movements of vessels Accidental Events Overboard loss of equipment or waste Spill of chemicals or hydrocarbons (< 1 tonne) Spill of chemicals or hydrocarbons (> 1 tonne) Trenching Concrete mattressing and rock material Positioning structures on seabed e.g., SSIV, wye manifolds Exclusion zone Physical presence Dropped objects Chemical, diesel or condensate spill Persistent spoil piles could snag fishing gear Could snag fishing gear Could snag fishing gear Exclusion from fishing grounds Increased collision risk. Increased vessel activity leading to increased collision risk. Could snag fishing gear Potential decrease in catch if stocks affected. Potential decrease in catch if stocks affected. Exclusion from fishing grounds The majority of activities have been assessed as potentially having an impact on commercial fisheries. The spatial extent of the impacts range from site-specific to local. The magnitudes will predominantly be low with a short-term duration. The likelihood, spatial extent, magnitude, duration and significance of the impacts have been assessed in Section K of Appendices 2.1 2.4. 10.1.4 Mitigation Measures Potential impacts requiring mitigation fall into two main categories: Those that could impact directly on fishing (e.g., exclusion zones, hazards which could snag nets). Those that affect fish stocks. Measures to mitigate the impact on fish species (namely reduced water quality and toxic effects of chemicals) have been previously outlined in Section 9.2.4. They have not been repeated in full CF00-00-EB-108-00001 Rev C1 Page 173 of 300

here but are summarised in Table 12-1 and provided in Appendix 2. The measures which will have a direct impact on commercial fisheries are detailed below: A 500m safety exclusion zone around the drilling rig(s), platforms and subsea infrastructure will be enforced. To reduce the likelihood of collision, the drilling rig, platforms and construction vessels will be appropriately lit and sound warnings will be broadcast in poor visibility. Via the Kingfisher Fortnightly Bulletins, Notices to Mariners and, where appropriate, VHF radio broadcasts users of the sea will be notified of: The presence of exclusion zones. The presence and intended movements of construction vessels. The presence of new structures, and areas of seabed covered by concrete mattressing or rock material. GDF SUEZ E&P UK will consider using a guard vessel to protect the pipelines for the period between being laid on the seabed and being trenched. The vessel will liaise with fishing vessels in the area to ensure that they are aware of the pipeline and risks involved with trawling over it. It has not yet been determined whether the pipeline will be buried mechanically or naturally. This decision will include assessment of the potential for snagging of fishing gear whilst the pipeline remains unburied. Profiles of the pipeline crossings will be designed to minimise snagging potential. Subsea structures will be designed to be fishing friendly with no snag points. A debris clearance survey will be conducted at the end of each construction phase and any significant objects will be removed. For any dropped objects that cannot be removed, GDF SUEZ E&P UK will submit a PON2 form to the DECC, MCA and NFFO to notify other sea users of the position of the obstruction. Pipeline integrity will be ensured by pre-commissioning testing. 10.1.5 Residual Impact Significance Assessment Mitigation measures have been assessed to be sufficient to reduce the impact on commercial fisheries in the area. However, there will be some residual impact and the significance of this has been discussed below. 10.1.5.1 Exclusion zones Permanent 500m radius safety exclusion zones will be established around the Cygnus A and B platforms. The safety exclusion zones will be enforced by a guard vessel and will be in force for the duration of field life (expected to be approximately 35 years). There is potential for fishing vessels to be displaced from their fishing grounds due to the presence of the new zones. Fishing activity in the region of Cygnus is moderate (based on days fished data, see above). However, as the exclusion area is small (1.6km 2 ) in comparison to the wider SNS fishing grounds it is unlikely that any impact will be significant. Overall the conclusion of the assessment was that the presence of the new exclusion zones will have a low residual impact on commercial fisheries. 10.1.5.2 Snagging hazards A number of subsea structures and residual footprints have the potential to present a snagging risk to fishing vessels. For example, anchor mounds created by the anchor lay barge, the wye manifold and SSIV. Given the nature of the seabed sediments (typically loose sands grading from coarse to fine with depth, see Section 8.4.2.3) such mounds are likely to disperse rapidly unlike more cohesive mounds resulting from i.e. drill cuttings, which can persist for 5 to 50 years (Backwell et al. 2000). As such the risk of fishing gear resulting from the presence of mounds is temporary. Subsea structures are designed to be fishing friendly i.e., they have raked sides that deflect trawl boards and will be within a 500m safety exclusion zone. Therefore, the mitigation measures are considered to reduce the risk of fishing gear snagging to an acceptable level and the residual impact significance has been assessed as low. 10.1.5.3 Accidental Events: spills of hydrocarbons (>1 tonne) Hydrocarbons produced at Cygnus include condensate and gas. As such, oil spill modelling presents the worst case spill scenario as a condensate spill resulting from a well blow out at CF00-00-EB-108-00001 Rev C1 Page 174 of 300

Cygnus. Modelling indicates that a spill resulting from a well blow out will travel up to a distance of 3km from the spill location before dispersing and evaporating (see Section 7.3 for further details). Vessels may be excluded from the affected area, although for short periods of time the fishing industry can generally relocate to other grounds without any detrimental impacts to catch. If fish stocks are contaminated there could be a loss of market confidence as people may be unwilling to buy fish caught in a contaminated area. However, this is not a significant proportion of the SNS fishing grounds and given the fact a spill of this magnitude is highly unlikely it has been concluded in the EIA that the residual impact is of low significance. 10.2 SHIPPING AND NAVIGATION 10.2.1 Baseline Data Sources This section makes use of the following data sources: Shipping intensity study undertaken for the Cygnus field development: Anatec (2011). Environmental Statement for the Cygnus Exploration well (GDF Britain 2005). Technical report on existing activities within SEA2: DTI (2001e). UK Offshore Energy SEA 2: DECC (2011b). 10.2.2 Existing Baseline The SNS experiences a relatively high density of shipping traffic which can be attributed to the presence of a number of international ports along the bordering coasts. Port traffic has increased nationally by 6% since 1989 and through-traffic in the North Sea is expected to increase by 2020 (DECC 2011b). As indicated on the Maritime Data website, shipping densities within the development area are classified as very high (Maritime Data website, 2011). Figure 10-6 gives an indication of shipping movements within the SNS and the location of the major ports (DTI 2001e). The main ports within the region include: Hull a commercial and passenger port, with roll-on roll-off (ro-ro) ferry services to Zeebrugge and Rotterdam. Grimsby commercial fishing port. Great Yarmouth a supply/fabrication base for the offshore oil and gas industry with ro-ro facilities and a ferry service to The Netherlands (GDF Britain 2005). CF00-00-EB-108-00001 Rev C1 Page 175 of 300

Figure 10-6: SNS shipping traffic Source: Cordah (1998) cited in DTI (2001e) A shipping traffic and collision risk assessment has been carried out for the Cygnus Field development (Anatec 2011). The study identified 16 shipping routes which pass within 10nm of the platforms. Table 10-4 presents these routes in ascending order of closest point of approach (CPA) and Figure 10-7 shows the mean shipping route positions relative to the Cygnus platforms. The total traffic volume on these routes is estimated to be 2,027 vessels per year (an average of 5-6 vessels per day). This is made up predominantly from cargo vessels, but also tankers and ferries (Figure 10-8). Of the 16 routes, routes 1,2,3 and 4 pass within 2 nm of Cygnus Alpha and routes 1,3,5,6 and 8 pass within 2nm of Cygnus Bravo. CF00-00-EB-108-00001 Rev C1 Page 176 of 300

Table 10-4 : Shipping routes passing through the development area Route No. Description CPA (nm) Ships Per Year Alpha Bravo 1 Seaham-Hamburg a 0.2 0.4 4 2 Baltic-Humber a Sound 1.4 4.1 18 3 Kattegat-Humber MacAndrews S* 1.5 1.2 102 4 Humber-Baltic a Sound 1.7 4.3 7 5 Seaham-Kiel Canal 2.1 1.4 20 6 Sunderland-Kiel Canal* 2.5 2.0 24 7 Immingham-Gothenburg DFDS b 2.6 5.2 78 8 Kattegat-Humber MacAndrews N* 3.1 1.2 102 9 Kiel Canal-Seaham 4.1 3.5 25 10 Tees-Kiel Canal* 4.4 5.0 184 11 Kattegat-Humber a* 4.9 7.4 919 12 Brevik-Immingham DFDS* 5.0 2.3 104 13 Humber-Norway S S* 6.1 3.4 120 14 Kattegat-Humber c* 7.8 10.4 252 15 Humber-Norway S N* 7.8 4.9 40 16 Tyne-Hamburg a* 8.0 7.5 29 Total - - 2,027 * Where two or more routes have identical closest point of approach and bearing they have been grouped together. In this case, the description lists the sub-route with the most ships per year. Source: Anatec (2011) Figure 10-7: Shipping route positions near Cygnus Source: Anatec (2011) CF00-00-EB-108-00001 Rev C1 Page 177 of 300

Figure 10-8: Vessel type distribution near Cygnus Source: Anatec (2011) The main collision hazard scenarios identified in the Anatec 2011 study are: Passing powered ship collision a passing ship collides with the installation when steaming on passage (under power). Passing drifting ship collision a passing ship collides with the installation due to suffering power failure, which results in the ship drifting under the influence of the prevailing metocean conditions (wind, wave and tide). Modelling has been run to calculate the estimated collision risk frequencies at each Cygnus platform for normal and drilling operations, for each scenario and is summarised in Table 10-5 below: Table 10-5: Estimated collision risk for the two main collision hazard scenarios at Cygnus Installations Annual ship collision frequency Corresponding collision return period (yrs) Comments Passing Powered Collision Risk Cygnus A Platforms Cygnus A Drilling Rig & Platforms Cygnus B Platform 9.9 x 10-05 10,150 1.5 x 10-04 6,900 3.9 x 10-04 2,600 This is below the historical average ship collision frequency for offshore installations on the UKCS Cygnus B Drilling Rig & Platform 8.1 x 10-04 1,250 This is greater than the historical average ship collision frequency for offshore installations on the UKCS (5.4 x 10-04 ). Passing Drifting Ship Collision Cygnus A Platforms Cygnus A Drilling Rig & 2.4 x 10-06 420,000 The low risk estimate reflects that this is generally a low probability event. No reported passing drifting ship collisions with oil and gas installations on UKCS in approximately 8,000 operational years. A large number of drifting ships have occurred each year in UK waters, the vessels have been recovered in time (e.g., anchored, restarted engines or taken in tow) or passed clear of installations. 3.2 x 10-06 310,000 The collision frequency for Cygnus A decreases when the rig is present as it provides shielding CF00-00-EB-108-00001 Rev C1 Page 178 of 300

Installations Annual ship collision frequency Corresponding collision return period (yrs) Comments Platforms from vessels drifting from the north easterly direction. However, the total collision frequency increases due to the larger target area for vessels to drift into. Cygnus B Platform Cygnus B Drilling Rig & Platform 1.3 x 10-05 77,000 As with Cygnus A, the low risk reflects the fact that this is a generally low probability event. 1.7 x 10-05 60,000 As with Cygnus A, the collision frequency for Cygnus B decreases when the rig is on site, but the total collision frequency for the installation increases due to the larger target area. Source: Anatec (2011) Table 10-6 below summarises the total collision frequencies at Cygnus for normal operations (platforms only) and drilling operations (platform and drilling rig). Table 10-6: Cygnus Total Collision Frequencies During Normal and Drilling Operations Platform Powered Collision Frequency Drifting Collision Frequency Total Annual Collision Frequency Return (years) Cygnus collision frequencies during normal operations Cygnus Alpha 9.9 x 10-05 2.4 x 10-06 1.0 x 10-04 9,900 Cygnus Bravo 3.9 x 10-04 1.3 x 10-05 4.0 x 10-04 2,500 Cygnus collision frequencies during drilling operations Cygnus Alpha 1.5 x 10-04 3.2 x 10-06 1.5 x 10-04 6,700 Cygnus Bravo 8.1 x 10-04 1.7 x 10-05 8.2 x 10-04 1,200 Cygnus Proposed Pipeline Shipping Review Shipping activity within 2nm of the proposed export pipeline route has been reviewed in the Anatec 2011 study and shows 134 vessels crossed the pipeline during the 67 day survey period, which corresponds to an average of two vessels per day. The most common type of vessel which crosses the pipeline is cargo vessels (51%) followed by tankers (30%). The other types of vessel were other (9%), fishing (5%), tug (3%) and dredger/subsea (2%). The majority of vessels cross the export pipeline towards the ETS pipeline tie-in near the Trent field, where the water is deeper (e.g., Trent platform, 46m). Cargo vessels and tankers prefer this area due to the deeper water. CF00-00-EB-108-00001 Rev C1 Page 179 of 300

10.2.3 Potential Impact Identification The EIA identified that during the project life cycle that the following project activities have the potential to interact with shipping and navigation (Table 10-7). Table 10-7 : Shipping and navigation - potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movements of vessels Production Physical presence / exclusion zones Presence of platform Physical presence / exclusion zones Physical presence and movements of vessels Accidental Events Spill of chemicals and hydrocarbons (> 1 tonne) Overboard loss of equipment or waste Physical presence Chemical, diesel or condensate spill Dropped objects Obstruction of shipping lanes leading to increased collision risk. Obstruction of shipping lanes leading to increased collision risk. Increased vessel activity leading to increased collision risk. Damage to vessels Restrictions on shipping lanes Could cause hazard to shipping The likelihood of activities affecting shipping and navigation was either assessed as possible or unlikely for all activities. If impacts were to occur they would be site specific, low to medium in magnitude with a short-term duration. The likelihood, spatial extent, magnitude, duration and significance of the impacts are presented in Section L of Appendices 2.1 2.4. 10.2.4 Mitigation Measures A 500m safety exclusion zone around the drilling rig(s), platforms and subsea infrastructure will be enforced. To reduce the likelihood of collision, the drilling rig, platforms and construction vessels will be appropriately lit and sound warnings will be broadcast in poor visibility. Other marine users will be notified of the presence and intended movements of construction vessels and the presence of new structures, via the Kingfisher Fortnightly Bulletins, Notices to Mariners and, where appropriate, VHF radio broadcasts. GDF SUEZ E&P UK will have a collision risk management plan in place for the proposed development, compliant with IMO standard requirements. All vessels will follow the IMO Standards and will be properly marked An OPEP will be in place to mitigate the impact of any spills and pipelines will be tested to ensure integrity. 10.2.5 Residual Impact Significance Assessment The majority of activities during both the construction and production phases have been assessed as having minimal impact on shipping and navigation and therefore have not been taken forward for a residual impact significance assessment (see Appendix 2). 10.2.5.1 Exclusion Zones 500m radius safety exclusion zones will be established around the platforms and drilling rig. The safety exclusion zones will be enforced by a guard vessel and will be in force for the duration of field life (expected to be approximately 35 years). The addition of these zones to the region could obstruct shipping lanes and lead to compression of routes more commonly used. Shipping studies undertaken by Anatec (2008a,b: 2009a,b; 2011) concluded that there is sufficient surrounding sea for vessels to manoeuvre around a fixed obstruction. CF00-00-EB-108-00001 Rev C1 Page 180 of 300

Given the high density of shipping in the SNS even considering the mitigation measures, it is still possible that the presence of the exclusion zones may lead to vessels re-routing. The residual impact of the presence of the platforms on shipping and navigation has been assessed as of low significance. 10.2.5.2 Accidental events: spill of hydrocarbons (>1 tonne) A loss of well control could result in a spill which if ongoing, could lead to the shipping lanes in the region being closed to facilitate emergency response operations to be implemented. Similarly, it is possible that shipping lanes could be routed around the affected area. There is the risk of economic impacts on shipping associated with longer routes and delays. Hydrocarbon spill modelling at Cygnus indicates that condensate resulting from a well blow out will travel up to 3km from the origin of the spill. Given the small area likely to be directly impacted and the rarity of such an event, a hydrocarbon spill at Cygnus has been assessed as having a low residual impact on the shipping activities. 10.3 OTHER MARINE USERS 10.3.1 Baseline Data Sources Sources of data include: Data on military practice and exercise areas (PEXA) Data from the Crown Estate on offshore windfarm areas and marine aggregate dredging sites: Crown Estate (2011) Oil and gas infrastructure data: UK Deal (2011) Cables data: KISCA (2011) Atlas of recreational boating: RYA (2008) 10.3.2 Existing Baseline The SNS is an extremely busy sea area, not only with regards to the oil and gas industry but for many other marine users. In addition to the numerous wells and platforms, a number of active and disused pipelines and cables cross the SNS. There are also several licensed marine aggregate extraction areas, military training areas, and licensed or potential sites for offshore windfarm developments (designated under Crown Estate licence rounds 2 and 3) (See Figure 10-9) (DECC 2011e). Sea users in the vicinity of the project area include: Other Operators (132 existing wells, 9 platforms and 35 pipelines within 40km of Cygnus A and Cygnus B). The Neatishead military training area, used for air combat training, is approximately 23km from the proposed Cygnus A platform location. The Doggerbank Round 3 offshore wind development area is situated approximately 16.5km northwest of the proposed Cygnus B platform location. 35 existing pipelines are located within 40km of Cygnus A and Cygnus B platforms, but no pipelines are located within Blocks 44/11a or 44/12a where the wells and platforms are located. The Cygnus export pipeline crosses the Cavendish gas export pipeline approximately 38km to the south west of Cygnus B. Recreational boating: a medium recreation use cruising route is located 40km north of the proposed Cygnus B platform location. There are several additional yachting routes, general sailing areas and racing areas near the coast but the development is far enough offshore for general sailing not to occur in the vicinity (RYA 2008). The closest marine aggregate extraction area is a prospective aggregate area 48km to the west of the proposed Cygnus B platform location. There is also an application/pre-application area 71km to the north of the Cygnus B platform. CF00-00-EB-108-00001 Rev C1 Page 181 of 300

1 0'W 0 0' 1 0'E 2 0'E 3 0'E 4 0'E Environmental Statement Figure 10-9: Other marine users Legend Proposed Project Development Cygnus A Hub Cygnus B NPAI Cygnus export pipeline Intrafield pipeline 55 0'N 55 0'N ETS tie-in Oil and Gas Infrastructure Platform Hydrocarbon field Aggregate Extraction Application and pre-application extraction areas Option and prospecting aggregate extraction areas Cables and Pipelines Pipeline Cable Windfarm Infrastructure and MOD Round 1 Wind Zone Round 2 Wind Zone Round 3 Development Zone Flamborough Head MOD PEXA 54 0'N 54 0'N Land Median line NOTE: Not to be used for navigation Date Monday, June 6, 2011 17:21:21 Projection ED 1950 UTM Zone 31N Spheroid International 1924 Datum D European 1950 Theddlethorpe Data Source File Reference GEBCO, JNCC, TCE, UKDEAL, MOD J:\P951\Mxd\O_Cygnus_ES\.mxd Figure_10-9_Other_marine_users Checked Produced By Reviewed By David Cook Anna Farley 53 0'N 53 0'N 0 0' 1 0'E 2 0'E 3 0'E 4 0'E km 0 5 10 20 30 40 50 Metoc Ltd, 2011. All rights reserved.

10.3.3 Potential Impact Identification The EIA identified that during the project life cycle the following project activity have the potential to interact with other marine users (Table 10-6). Table 10-8 : Other marine users - potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movement of transportation Production Presence of platforms Physical presence and movement of transportation Accidental Events Overboard loss of equipment or waste Spill of chemicals and hydrocarbons (> 1 tonne) Physical presence / exclusion zones Physical presence / exclusion zones Dropped objects Chemical, diesel or condensate spill Increased vessel activity and obstructions to shipping lanes leading to increased collision risk. Potential collision risk. Could cause hazard to shipping Restricted access The likelihood of activities affecting other marine users was assessed as unlikely. If impacts were to occur they would be site specific, low in magnitude with a short-term duration. The likelihood, spatial extent, magnitude, duration and significance of the impacts are presented in Section M of Appendix 2.1. 10.3.4 Mitigation Measures Marine users will be notified of the presence and intended movements of construction vessels and the presence of new structures via the Kingfisher Fortnightly Bulletins, Notices to Marine and, where appropriate, VHF radio broadcasts. In addition GDF SUEZ E&P UK will have a collision risk management plan in place for the proposed development, including the deployment of a guard vessel on station. Construction of the pipeline crossings over the Cavendish gas export pipeline and Tyne to Trent infield line to will be undertaken under crossing agreements established with RWE Dea UK Ltd and Perenco. GDF SUEZ E&P UK will comply with any conditions attached to these agreements. In addition, safety precautions will include as a minimum a separation distance of 50m between the trenching plough and the buried pipelines. 10.3.5 Residual Impact Significance Assessment The industry standard best practise measures are considered to be sufficient to reduce the impact on other marine users in the area. As such, they have not been taken forward for residual impact significance assessment (see Appendix 2). CF00-00-EB-108-00001 Rev C1 Page 183 of 300

10.4 ARCHAEOLOGY 10.4.1 Baseline Data Sources This section has made use of the following sources: Technical report on prehistoric archaeological remains to inform SEA2 and SEA3 (DTI 2002) and the Offshore Energy SEA (DECC 2009c). Admiralty chart for the region: North Sea Offshore Chart Sheet 11, area 266. 10.4.2 Existing Baseline The North Sea has not always been flooded. Over time, sea level has retreated backwards and forwards leaving certain areas between the landmass now known as Britain and Europe exposed and habitable by humans. One such area was Doggerland, which extended across the entire North Sea up to the Norwegian trench. Although little is known about the geochronology and palaeoenvironment of the Dogger Bank and SNS, reports suggest that the majority of this area remained exposed and accessible throughout the Devensian Period (c48,000 12,000 BP) (DECC 2009c). As climate changed during the Holocene period (after c12,000 BP), the area is likely to have represented a resource rich alluvial plain attractive to humans (DECC 2009c). As a result, prehistoric landscapes and artefacts could be present all across the North Sea, although certain areas are likely to be more interesting than others from an archaeological point of view. To date, all recorded sites of retrieved prehistoric artefacts in the North Sea have been found in areas of depression or areas of lower ground. For this reason, the extensive depression south of the Dogger Bank and through the Outer Silver pit is of interest to archaeologists. Figure 10-10 shows that Doggerland covered the entire SNS and ancient river systems criss-crossed the region. The project area is positioned in the middle of what would have been Doggerland, approximately 25km north of the Outer Silver Pit. Figure 10-10: Speculative reconstruction of the river courses across the North Sea floor CF00-00-EB-108-00001 Rev C1 Page 184 of 300

Note: Reconstruction based at the time of the Late Glacial cold stadial when the area of dry land was at a maximum. Source: After Coles and Rouillard cited in DTI (2002). Two periods are of particular importance in terms of the potential for archaeological finds from the Dogger Bank region: The Mesolithic period (~12,000 10,000 years BP) The Pleistocene period (1.8mya 10,000 years BP) During the Mesolithic period (also known as the Middle Stone Age), it is likely that humans occupied the lower valleys in the Dogger Bank area, and may have used the higher ground for hunting. Human artefacts, flints, spear-heads and mammal remains have all been dredged from locations reported as the Dogger Bank (DTI 2002), believed to be from the upper surface of the Bank. It is also possible that items could have originated and been preserved south of the Dogger Bank where a vast lagoon existed from 8,000 7,000 years BP. Artefacts are also expected in the area known as the Outer Silver Pit, which was a narrow channel connecting a shallow sea basin to the open North Sea around 7,500 years BP. The Dogger Bank region has also been important for Pleistocene fauna, with mammoth and rhinoceros teeth trawled from the area. It is possible that further relicts could be recovered, particularly the zone on the edge of Silver Pit and in the region which is now at a depth of approximately 40m. Finding them would depend upon the thickness of the modern marine sediments and due to the hostile conditions in terms of waves, wind and currents, searches for prehistoric materials would only be undertaken in areas with considerable knowledge that artefacts were present (DTI 2002). Wrecks Wrecks are considered conservation areas and are afforded statutory protection under two main provisions: The Protection of Wrecks (Designation) Order (2002) and the Protection of Military Remains Act 1986 (Designation of Vessels and Controlled Sites) (amendment) Order 2003. Admiralty charts for the area show that whilst there are several wreck sites within the Dogger Bank, none are within the immediate vicinity of the project area. The site survey of the Cygnus A to ETS pipeline tie-in identified a wreck 800m north west of the proposed route centre line. The wreck is broken up and rises to 4.5m above the seabed with surrounding debris identified to rise to 1.1m. It has not been identified as having a protected status. 10.4.3 Potential Impact Identification The EIA identified that during the project life cycle the following project activities have the potential to interact with archaeological remains (Table 10-9). Table 10-9 : Archaeology - potential impact identification Project Activity Aspect Potential Impact Construction Physical presence and movement of transportation Installation of infrastructure Physical presence and movement vessels Installation of infrastructure Accidental Events Overboard loss of equipment or waste Positioning structures on seabed e.g., jack-up legs, platforms, anchors, subsea structures Use of thrusters in shallow water Trenching Dropped objects Could disturb or damage currently unknown maritime archaeological features. Could disturb currently unknown maritime archaeological features. Removal of protective overburden can leave remains with insufficient cover to protect them from activities such as trawling. Could disturb currently unknown maritime archaeological features CF00-00-EB-108-00001 Rev C1 Page 185 of 300

The likelihood of activities affecting archaeology was assessed as possible for all activities. If impacts were to occur they would be site specific, low in magnitude with a short-term duration. The likelihood, spatial extent, magnitude, duration and significance of the impacts are presented in Section N of Appendix 2.1. 10.4.4 Mitigation Measures The British Marine Aggregate Producers Association (BMAPA) has produced a protocol for reporting finds of archaeological interest (Wessex Archaeology 2005). This has the specific aim of reducing adverse effects of marine aggregate dredging on the historic environment. However, it is equally applicable to other industries working in the North Sea. These protocols will be followed in the event of discovery of artefacts on the seabed, which could potentially be of archaeological significance. 10.4.5 Residual Impact Significance Assessment No archaeological features, other than the wreck, were identified during the site surveys undertaken in 2011. In the unlikely event of an unforeseen site discovery, the proposed mitigation measures would ensure damage to the site would be minimised and the nature of the discovery properly reported. It is therefore likely that any damage would be of low significance, while the value of the discovery may be of moderate/major (positive) significance. Activities undertaken during construction are not anticipated to have a significant impact and have therefore not been taken forward for residual impact significance assessment (see Appendix 2). CF00-00-EB-108-00001 Rev C1 Page 186 of 300

11.0 CUMULATIVE AND INDIRECT IMPACTS As discussed in Section 4.2, the EIA has given consideration to cumulative and indirect impacts and interactions. The definitions of these three types of impact overlap, generally without any agreed and accepted definitions. For the purposes of this assessment, the definitions proposed by the European Commission (1999) have been used. The definitions are as follows: Indirect Impacts (secondary impacts) Impacts on the environment, which are not a direct result of the project, often produced away from or as a result of a complex pathway. Cumulative Impacts Impacts that result from incremental changes caused by other past, present or reasonably foreseeable actions together with the project. Impact Interactions The reactions between impacts whether between the impacts of just one project or between the impacts of other projects in the area. It is difficult to quantify indirect impacts due to the project but where possible this was undertaken as part of the main EIA. For example, the potential for chemicals to bioaccumulate up the food chain and affect the top predators such as seabirds and marine mammals. In addition, the EIA also considered cumulative impacts from similar activities within the project e.g., the combined effects on habitat loss from numerous types of seabed disturbance. The results of this assessment are therefore discussed in Sections 9, 10 and 11 and in Appendix 2. This Section focuses on the potential for cumulative and indirect impacts and interactions relative to Cygnus and: Past and future oil and gas developments (Section 11.1). Other seabed/marine users e.g., commercial fishing, wind farms, marine aggregate extraction (Section 11.2). Climate change (Section 11.3). 11.1 OIL AND GAS DEVELOPMENTS The Cygnus field is one of the most northerly fields to be developed in the SNS gas basin. The basin is a mature gas producing area with around 100 platforms and associated gas fields. Due to the continuing use of the region for production and exploration there is the potential for cumulative impacts on the environment. Through its participation in the SNS Environmental Network GDF SUEZ E&P UK are aware that in addition to the activities planned within the Cygnus area, the development programmes listed in Table 11-1 are planned for the near future. In addition 89 new licence blocks in the SNS were awarded in the 26th oil and gas licence round. These have varying levels of commitment, but there are two firm commitments to drill a well following further technical investigations and 26 require that a firm commitment to drill a well is made to the DECC within two years or the licence is dropped (DECC 2011d). Figure 11-1 demonstrates the proximity of the known development opportunities in relation to Cygnus and the existing infrastructure in the region. The predominant cumulative impacts of oil and gas development activities include, but are not limited to: Deterioration in local air quality. Deterioration in water quality. Disturbance of seabed sediments resulting in change of composition and/or contamination. Disturbance of habitats or species. CF00-00-EB-108-00001 Rev C1 Page 187 of 300

Table 11-1 : Past, present and planned developments in the vicinity of Cygnus Company Activity Block Closest distance to project (km) Planned / Completed GDF SUEZ E&P UK GDF SUEZ E&P UK Centrica Cygnus appraisal drilling 4 wells 44/12 3 Completed between 2009 and 2010 Cygnus exploration well 44/12 3 Completed 2005 Carna Potential for development although appraisal well drilling appears to have been delayed ConocoPhillips Katy (previously Harrison) Field is expected to be developed with a single well on a NPAI connected to the Murdoch field centre Centrica Wintershall Dana GDF SUEZ E&P UK RWE Dea UK Ltd Ensign - Two platform wells, subsea well tied back to Audrey A platform by 2km production pipeline. Unmanned production facility. Wingate - NPAI with six well slots tied-back via new 20km pipeline to D15-A platform. One well to be drilled per year Platypus Appraisal well under consideration. Juliet field development two subsea production wells tied back to host platform Clipper South five wells supported by a NPAI tied-back to the LOGGS facility. RWE Dea UK Ltd Breagh Development Phase 1 field to be developed through a NPAI, drilling 7 wells and laying a 100km pipeline between the NPAI and Teeside Source: Noroil Publications (2011) 42/21 and 43/22 17 Postponed 44/19 21.5 Planned June 2012 48/4 and 48/15 33 Planned Q3 2011 44/24 33 Pipeline completed 2011. Platform installation and drilling planned Jul/ Aug 2011. 48/1 45 Planned 47/14 ~95 Planned 2012 48/19 and 48/20 100 In Progress 42/13 115 In Progress CF00-00-EB-108-00001 Rev C1 Page 188 of 300

0 0' 1 0'E 2 0'E 3 0'E 55 0'N Environmental Statement Figure 11-1: Oil and Gas cumulative impacts Legend Proposed project development Cygnus A Hub Cygnus B NPAI Cygnus export pipeline Intrafield pipeline 54 30'N 54 30'N ETS tie-in Cables and Pipelines Pipeline Telecom cable Out of service cable Oil and Gas Platform Wells UKCS Block Median line 54 0'N 54 0'N Land Date Monday, June 13, 2011 18:43:04 Projection ED 1950 UTM Zone 31N 53 30'N 53 30'N Spheroid Datum International 1924 D European 1950 Data Source GEBCO, KISCA, UKDEAL, File Reference J:\P951\Mxd\O_Cygnus_ES\.mxd Figure_11-1_Oil_and_Gas_cumulative_impacts Checked Produced By Reviewed By Penny Wilson Anna Farley 0 0' 1 0'E 2 0'E 3 0'E km 0 5 10 20 30 40 50 Metoc Ltd, 2011. All rights reserved.

11.1.1 Deterioration in local air quality The EIA concluded that the meteorological conditions in the SNS were of sufficient strength to enable rapid dispersion and dilution of CO, SOx and NOx emissions from construction and production activities. Air dispersion modelling indicated that gas concentrations would be significantly below guideline levels for human health and environmental protection within 500m of the discharge point i.e., from either a vessel or a platform (see Section 8.1.5.1). The majority of the Cygnus construction and production emissions will occur around the proposed Cygnus A platform location, 15km from the nearest existing installation and 155km from the North Norfolk coastline. The nearest planned development is approximately 17km west of Cygnus. Cygnus is considered to be a sufficient distance from any planned or existing developments that emissions will not accumulate to deteriorate air quality. 11.1.2 Deterioration in water quality During construction and drilling of wells within the field, there is likely to be chemical discharges including discharges of WBM. The chemicals discharged during the drilling programme are relatively benign, the majority being risk assessed by the CEFAS as HQ colour band Gold or OCNS category E. These are categories for products that present the lowest hazard to the environment. Residual currents are such that chemical discharges are likely to be rapidly diluted and dispersed (see Section 8.3.5). The discharge of these chemicals will be short lived and wells will be drilled sequentially reducing any combined toxic impacts. 9.5kg of condensate could be discharged from Cygnus A per day in produced water, although it is considered that 0.95kg is most likely with normal production. Of the ten permanent gas installations within the Dogger Bank csac currently only the Tyne platform discharges produced water; although the Wingate platform will also discharge produced water when it starts production in fourth quarter 2011. The condensate dissolved and dispersed in the produced water will rapidly disperse and biodegrade in the surrounding water column. Historic research has shown that, due to the rapid dilution and low concentrations and low toxicities of contaminants in produced water, discharges in the North Sea have low potential for biological impact (Wills 2000). Dilutions required for no observed effect concentration (NOEC) are achieved within five minutes, and between 10 to 100m from the discharge point. The nearest discharging platform (Tyne) is 18km south east of Cygnus A and at this range it is not conceivable that Cygnus A would have a material impact on the area causing the NOEC to be exceeded. As a result, it is considered that as exposure times are short, acute toxic effects on species are unlikely (Wills 2000). ROV surveys around platform jackets show profuse marine life which supports this conclusion. Long term or chronic effects are also unlikely given the minimal contaminant levels in produced water (UKOOA 1999). It has been suggested that contaminant levels in discharges may affect plankton larvae (Wills 2000), but more work is required by the industry on the amounts, fates and effects of toxic heavy metals in produced water before any significant conclusions can be drawn. Given the mitigation measures in place and the distance to the nearest permanent discharging facility, cumulative effects on water quality are unlikely. 11.1.3 Disturbance of seabed sediments As discussed in Section 6.1.3, the Cygnus development will disturb approximately 1.46km 2 of seabed during construction. The EIA has concluded that the development will have a low impact on seabed sediments. A minor fining of sediments may be noticeable around the drill centres, associated with drill related discharges, whilst more clay based sediments may be brought to the surface along the export pipeline route. In general, although disturbed the composition of surface sediments in the development area will remain unchanged. The site investigation undertaken in 2009 subsequent to drilling (UTEC Survey Ltd 2009b) recorded fining of sediments as a consequence of drilling related discharges up to 300m around the Cygnus exploration well head i.e., approximately 0.28km 2. It can be assumed that the proposed wells will have a similar impact on sediments at each of the proposed drill centres. 136 wells have been drilled in the Dogger Bank csac and 17 wells are known to be planned for the near future (including the 10 covered by this document), of these 42 were or will be in water depths of less than 20m i.e., on the main designated feature. Assuming a similar level of impact at the 42 drill sites on the Bank, approximately 11.76km 2 of sediment would show a marginal increase in fines compared to the generally fine sand of the Bank. This represents 1.07% of the sandbank feature, which is approximately 1,100km 2. CF00-00-EB-108-00001 Rev C1 Page 190 of 300

Generally, sediment contamination in the project area is below background concentrations for the SNS. Evidence from the post-drilling sediment samples acquired at the Cygnus exploration well site during surveys in 2009 (UTEC Survey Ltd 2009b) suggests that sediments will remain largely uncontaminated after drilling. Elevated concentrations of THCs may be noted, as a result of pyrolytic fallout and discharge of WBM, but in general heavy and trace metal concentrations will show little change compared to background levels. Assuming that contaminants are dispersed at the other drill sites in the area, Cygnus will add to the marginal increase in anthropogenic related contamination but is unlikely to change the status of sediments from unpolluted to polluted. 11.1.4 Disturbance of habitats or species Drill cuttings It is possible that a number of the proposed developments detailed in Table 11-1 may be under construction at the same time as Cygnus. Although the drill cuttings piles for the Cygnus wells (at their respective drill centres) have the potential to overlap (see Section 6.1.3), the proposed developments are a sufficient distance from Cygnus that there is no potential for an overlap of footprints. Therefore there is not considered to be any potential for cumulative impacts on habitats or benthic species as a result of this aspect of the development in combination with any other development. Pipeline burial The potential developments described within Table 11-1 will incorporate pipeline installation activities. It is currently unknown whether these are likely to be undertaken in a similar timeframe to the Cygnus project. The distances provided in Table 11-1 from the Cygnus development are the minimum and it is likely that pipeline laying activities will be further away than suggested. The closest planned activities are at least 21.5km away. It is considered that the there are unlikely to be any significant cumulative impacts from pipeline laying activities at this distance, however the progress of these projects will continue to be monitored and if it is determined that activities are likely to coincide, mitigation measures will be considered as appropriate. Habitat loss or change A number of activities associated with the development will involve the permanent placement of structures, rock material or concrete mattresses on the seabed. It is estimated that approximately 0.0396km 2 ) of habitat will be lost under these deposits, of which approximately 0.035km 2 is within the Dogger Bank csac. The majority of the structures, rock material and mattresses will be placed in the shallow waters on top of the Bank or its northern flank. Evidence from the postdrilling seabed clearance survey for the Cygnus exploration well suggests that within three months of rock material being placed on the seabed it will either be dispersed or covered with sand (Rudall Blanchard Associates 2008). There are ten permanent gas developments within the Dogger Bank csac boundary. In addition, GDF SUEZ E&P UK is aware of six other instances where rock material has been used within the Dogger Bank csac for emergency rock deposition. However, a certain amount of rock material has been used in pipeline trench transition areas and pipeline crossings. Table 11-2 presents a very approximate estimation of the area of seabed covered by permanent structures or deposits, along with the assumptions made to derive the end figure. The calculations estimate that approximately 0.034km 2 of seabed within the Dogger Bank csac boundary has been covered by permanent structures or rock material, 0.0003% of the csac area. The addition of the Cygnus development, will increase this coverage to 0.044km 2 of seabed, 0.0004% of the csac. CF00-00-EB-108-00001 Rev C1 Page 191 of 300

Table 11-2 : Estimated footprint of gas developments in the Dogger Bank csac Activity Assumptions Footprint (km 2 ) Permanent gas developments Rig stabilisation Pipeline crossings Cygnus field development Cavendish Tyne platform and offshore barge Munro and Kelvin Assumes that NPAIs are similar size to Cygnus B and Wingate. Footprint includes platform and concrete mattressing at export pipeline route trench transition areas. 0.001334 0.001048 0.001588 Wingate Footprint taken from Wingate ES. 0.000794 Murdoch platform complex Subsea tiebacks - McAdam, Hawksley, Hunter, Rita. Assumes the three platforms have a similar footprint to the platforms at Cygnus A. Assumes 7 trench transition areas and that each subsea development consists of one well. Cygnus exploration well, 44/17c-M1z, 4 Cygnus appraisal wells. Footprint is based on average footprint from the Cygnus appraisal wells determined from post-deposition survey. Assumes that the five pipeline crossings identified on geographical information system (GIS) will be similar to the proposed Cygnus pipeline crossings For structures within Dogger Bank csac (e.g., platforms, SSIV, rock material and concrete mattressing) 0.00196 0.0031 0.0072 0.0168 0.0396 Total - 0.0734 Subsea Noise The loudest manmade, non-military, sources of marine noise are generated by seismic surveys and pile driving. As described in Section 9.5, it is marine mammals that, in general, show the highest sensitivity to acoustic disturbance and the potential significance is usually related to the abundance of animals in the area likely to be affected. The noise related impacts of pile driving at Cygnus were assessed in Section 9.5.3. There is a high possibility that the effects identified from Cygnus will be experienced in combination with impacts from sources outside of the project, principally from seismic survey associated with the oil and gas 26th and potentially 27 th licence rounds. It is probable that activities will be audible to marine mammals over much of the North Sea (DECC 2009d). Operators are only required to make survey extents publicly available 28 days prior to survey mobilisation such that specific information on seismic survey schedules for 2012 through to 2014 were not available at the time of ES submission. As such a quantitative assessment of the cumulative impact from other oil and gas projects cannot be conducted. Instead qualitative information has been drawn from the Offshore Energy SEA (DECC 2011b), which considers the potential for cumulative effects on regional seas. The SEA assessment is based on: Defining the possible spatial effect ranges of activities; based on source level characterisations, sound propagation characteristics and effects thresholds. Considering the potential for significant effects, using criteria recommended by the JNCC guidelines to the OMR, and noise levels in relation to biologically meaningful disturbance effects. Consideration of potential activity levels, and specific sensitivities of individual Regional Seas. CF00-00-EB-108-00001 Rev C1 Page 192 of 300

Identification of specific geographical areas of concern. Consideration of requirements for seasonal avoidance. Consideration of operational mitigation. Consideration of potential cumulative effects. The report concludes that the spatial scales over which either observable or biologically meaningful effects are likely to result do not support significant groups of animals. This conclusion is qualitatively compatible with conclusions reached by previous SEAs e.g., that The balance of evidence suggests that effects of seismic activities are limited, in species present in significant numbers to behavioural disturbance, which is likely to be of short duration, limited spatial extent and of minor ecological significance. The numbers of individuals likely to be influenced represent a small to moderate proportion of biogeographic populations. (SEA 7 quoted in DECC 2011b). This, combined with the relatively limited temporal and spatial extent of Cygnus piling activities suggests that cumulative impacts will be limited. However, GDF SUEZ E&P UK will monitor seismic and piling activity in the region to determine whether any activities will occur simultaneously with the platform, wye manifold and SSIV piling. If any are identified the conclusions with regards cumulative impacts will be reassessed and schedules changed if operationally possible and if appropriate. 11.2 OTHER MARINE USERS In general, there are two main cumulative impacts that have to be considered when assessing the effects of a project on the surrounding region. These are: Whether the combined footprints of activities overlap potentially exacerbating environmental impacts from either project. Whether separate projects, although not overlapping, combined will result in the loss or disturbance of substantial areas of a particular regional habitat. 11.2.1 Commercial Fishing The Dogger Bank region is an important area for commercial fisheries. As discussed in Section 10.1, the development is within an area which contributes 36% to the average annual values caught in the region. However, whilst the site is valuable the CPUE is relatively low, indicating that a considerable amount of effort is imparted to land this value. Demersal species represent ~84% of the catch and are caught mainly using trawls. Beam trawls penetrate the seabed up to 8 cm deep (FAO 2011) and often leave visible scars on the seabed. The duration that the scar remains visible depends on the upper sediment layer and on the hydrographic conditions. On sediments consisting of medium to coarse sand tracks can remain visible for up to six days, whilst in fine sands they have been observed to disappear in 37 hours (FAO 2011). There is the potential for two types of cumulative impacts, one relating to physical disturbance of the seabed and one to the effects on marine ecology. The ES has demonstrated that, given the highly dynamic environment on top of the Dogger Bank, physical disturbance, as a result of construction activities, is unlikely to be noticeable above background levels within a few months of the activities ceasing. In the lower energy environment to the south of the Bank it is possible the scarring may take longer to disappear. Although the footprints of the two activities will overlap the benthic communities in the project area are characteristic of sandy sediment types subject to moderate disturbance. The ES concluded that benthic communities will recover from construction activities within three months to two years. The community type in the project area is typical for the region and it is considered that the combination of disturbance from trawling and construction will not cause a significant loss of habitat type or change in community structure. 11.2.2 Offshore Wind Farms Offshore wind farms are becoming more prevalent in UK waters. The Dogger Bank Round 3 offshore wind development area is located 20km northwest of the Cygnus field. Forewind, the developer, has agreed with The Crown Estate a target installed capacity of 9GW, although there is CF00-00-EB-108-00001 Rev C1 Page 193 of 300

potential within the area to achieve 13GW. If fully developed, it is likely to be the world s largest offshore wind project. Forewind plan to develop the area in four stages, or tranches, from Tranche A to D. Each tranche will be further sub-divided into three similar sized projects. Tranche A is located in the south western section of the area and covers 2,000km 2. The three projects within the tranche will be completed each with a generating capacity of 1.4GW. The first project, Project One, will comprise: Wind farm array Offshore collector and converter substations Offshore operations and maintenance infrastructure e.g., accommodation platforms, permanent moorings and navigational buoys Subsea inter-array cables: between the turbines; between the turbines and substations; and between substations Offshore meteorological masts and metocean equipment An export cable to a landfall at Cottingham in the East Riding of Yorkshire Up to two onshore converter substations with associated infrastructure Figure 11-2 illustrates the location of Tranche A and the cable corridor that is being considered in relation to the Cygnus project. A Scoping Report was submitted by Forewind to the Infrastructure Planning Committee in October 2010 identifying the areas that will be considered in the EIA (Forewind 2010). Figure 11-2 : Dogger Bank Tranche A and Project One Source: Adapted from www.forewind.co.uk CF00-00-EB-108-00001 Rev C1 Page 194 of 300

Offshore wind turbine technology is evolving rapidly and Forewind anticipate that machines between 3.6MW and 12MW may be available within the timescales of the project. This results in a range of possible dimensions and numbers of turbines that may be required. Forewind estimate that the array could consist of between 117 and 389 turbines (Forewind 2010). In addition, a wide range of foundation options are potentially available for use on the project, depending on the outcome of site investigations and environmental assessment. The types being considered are: 1) Monopile 2) Jacket 3) Tripod 4) Gravity base structure 5) Suction caisson Types one to three would require pile driving to secure structures. The main activities that could interact with the Cygnus project to generate cumulative impacts are: Pile driving Seabed levelling (for gravity bases and suction caissons) Cable trenching Scour protection and cable crossings deposition of protective aprons, mattresses, rock and gravel material The most significant types of cumulative impacts are likely to be generation of subsea noise from pile driving and the potential habitat loss or change in habitat as a result of physical disturbance. These impacts are discussed below. Subsea noise There are two main concerns relating to the cumulative impacts of subsea noise from projects in the same region. Both are related to the impact of received noise levels on marine mammals. The primary concern, as illustrated in Figure 11-3, is that animals may receive higher dose levels or the combination of projects may exclude animals from a larger extent of territory than one project on its own. Figure 11-3 : Cumulative noise impact scenarios The outline programme for Project One indicates that construction activity will commence in 2015 through to 2017 (Forewind 2010). The proposed Cygnus development schedule is for piling activity on the platforms and subsea infrastructure to be complete by the end of 2014. It is unlikely that the two activities will overlap and therefore it is expected that the cumulative noise impacts discussed above will be not be experienced. CF00-00-EB-108-00001 Rev C1 Page 195 of 300

A secondary concern is that increased noise levels in a region over subsequent years could cause marine mammals to avoid territorial habitats over an extended period of time. This could indirectly impact the viability of populations by affecting breeding, mating, migration or feeding. For example, an individual project may cause animals to avoid an area for a season which on its own may not be a problem. However, if a second project has the same effect the next year and a third the year after the distribution of species may be adversely affected. As construction activity at Project One will occur in the years following the Cygnus construction there is a possibility that this cumulative impact could be of concern. However, the scale of piling activity at the two developments is significantly different. At Cygnus eighteen piles will be driven to secure the platforms in place. Each pile typically takes six hours to drive, which leads to the assumption that pile driving will take up to 120 hours (5 days), although this is unlikely to be over a continuous period of time. Project One will involve the installation 117 to 389 turbines over three years, or 39 to 130 per year. Depending on the foundation base selected either one large monopile of 8.5 to 11m in diameter would be used per turbine or three to four 1.5 3m diameter piles per turbine. Both options would involve substantially longer pile driving durations and it is likely that subsea noise levels would be elevated for a significant period of time. As Project One is still in the design stage and no assessment of noise levels has been published it is difficult to quantify the cumulative impact. However, as pile driving at Cygnus is of a very limited duration in comparison to Project One it is not expected that the two projects will have a measurable cumulative impact. Habitat loss or change The Dogger Bank is a unique sandbank feature that is designated as a csac under the EC Habitats Directive. The main conservation objective is to ensure the favourable condition of the protected feature. The JNCC have identified six main pressure categories which may cause deterioration of the natural habitat; two of which are physical loss and physical damage. The Bank is considered to be moderately to highly sensitive and vulnerable to activities which would cause physical loss of habitat or physical damage 1 (JNCC 2010a). One concern is that development on the Bank will change the habitat type from one dominated by sand to one dominated by harder substrates such as rock and gravel as a result of the scour protection measures used by the different industries. Section 11.1.4, concluded that the Cygnus development and other oil and gas projects in the Dogger Bank will have a cumulative footprint of 0.044km 2, equivalent to 0.0004% of the csac area. Project One is also within the boundary of the csac however the project isn t far enough along in the design process to determine what the physical footprint will be. However, it is thought that the area of habitat lost under permanent structures will not be large and it is not expected that the cumulative impacts from the two industries will cause a significant loss or change in habitat. Navigation restrictions A combination of: the exclusion zones around the Cygnus development; the presence of Project One; and subsequent tranche projects, may squeeze shipping routes. As routes are squeezed shipping density along routes could increase and as a result the potential for collisions. The EIA has identified that any residual impact on shipping as a result of the Cygnus development will be of low significance, provided mitigation measures are implemented. Forewind are undertaking a large scoping exercise to ensure that Project One and any future projects will have a minimal impact on navigation. It is therefore considered that there will be a very small cumulative impact between the projects but that provided the shipping industry is kept well informed the impact should not be significant. The potential for problems with access to the Cygnus development as a result of the Forewind activities is not considered significant, however consultation with Forewind will continue throughout the development life to ensure there are no conflicts. 11.2.3 Marine Aggregate Extraction Areas The closest licensed marine aggregate extraction area is 48km to the west of the Cygnus development. Impacts on the marine environment from aggregate extraction primarily relate to the 1 For example, the permanent construction of oil and gas infrastructure, windfarms and cables; and the physical disturbance of the seabed caused by anchoring, pipeline and cable burial and placement of rock material. CF00-00-EB-108-00001 Rev C1 Page 196 of 300

direct disturbance of the seabed and the corresponding effects on marine ecology. Impacts are generally restricted to the area of seabed licensed; although, depending on the dredging activity and prevalent hydrodynamic conditions, sediment plumes from aggregate screening may impact benthic communities in an area up to a few kilometres from the license zone. The majority of impacts caused by activities at Cygnus will be limited in extent to the immediate area surrounding the project footprint. Drill cuttings discharged from the rig may be deposited up to 375m from the proposed drill centres, but deposits will be patchy in nature and undetectable against background levels. The footprints of the two activities will not overlap and cumulative impacts are not expected. In addition, marine aggregate extraction generally targets sublittoral sands and gravels, which support a reasonably diverse biological community different to the essentially sparse community found on the fine sands in the Cygnus project area (see Section 9.2). Therefore, there will not be any regional impacts from the combined disturbance/loss of habitat types. 11.3 CLIMATE CHANGE As discussed in Section 8.2, CO2 emissions from the Cygnus development will be a small contributor to climate change. However, it also possible that impacts from the development may interact with impacts related to climate change to exacerbate physical and biological changes in the environment. Climate change is likely to change the physical and biological baseline environment in the project area over the next 10-25 years, however the draft conservation objectives for the Dogger Bank note: "the vulnerability of the SAC to climate change is not considered given the uncertainties surrounding the effects of global change on the ocean (JNCC 2010a). The following impacts on the project area could be expected as a consequence of climate change: General increase in water depth due to sea level rise This will slightly affect tidal currents, wave propagation and mobility of seabed sediments (HR Wallingford 2007). However, any changes are likely to be incremental within the project area and within the ranges of survey error. The predicted sea level rise will not affect tidal current direction of strength (HR Wallingford 2007). Change in ocean acidity and temperature Due to the shallow nature of the Dogger Bank site the project area is expected to experience the full changes in ocean acidity and temperature rises predicted (JNCC 2010a). Minor changes are expected to occur over the next 10-25 years, with major biological shifts potentially occurring in the longer term i.e., 100 years. Although, it is unknown how the regions biological communities will be affected, there is the potential that there will be rapid alterations in the nature and structure of benthic communities. There may also be a northward migration of benthic and pelagic species as spatial temperature thresholds for species change and negative impacts on shell and skeleton-forming species are expected by 2100 (MCCIP 2011). The EIA identified the Cygnus development will not have any residual impacts on water depth, wind speed or wave conditions. Residual impacts on the environment will be short-term, predominantly affecting marine ecology. As climate change has the potential to affect the biological baseline it is possible that the project can interact with climate change to exacerbate this impact. However, the EIA concludes that following construction, biological communities are anticipated to recover to preimpact levels/structures or similar within three months to two years (see Section 9.1). Although, it is predicted that within the project area changes to the biological baseline as a consequence of climate change are expected to occur, only minor changes are anticipated in the next 10-25 years. Given the short timescale of the construction impacts it is considered unlikely that the project and climate change will cumulatively have significant impacts on marine ecology. 11.4 TRANSBOUNDARY IMPACTS The proximity of the UK-Netherlands median line (closest point 35km) also means that transboundary effects must be considered. This will include interaction between the human environments either side of the boundary and the potential for impacts to protected sites or species within UK waters to transfer into protected sites in Dutch waters. The scale and consequence of any trans-boundary effects will be comparable, or less, than those in UK waters. CF00-00-EB-108-00001 Rev C1 Page 197 of 300

The worst-case scenario oil spill modelling conducted to inform the EIA (presented in Section 7 and Appendix 4) indicates that condensate / diesel will travel 2 to 3km from the spill location, meaning the leading edge of the spill will still be 32km from the closest international boundary. In addition, cuttings dispersal modelling for the Cygnus exploration well (using PROTEUS) and similar modelling of other SNS wells indicate that drill cuttings become indistinguishable from sediments within 4.6km of the well location. These project aspects and all others with a potential to interact with environmental receptors have been fully considered and mitigated against, and therefore the EIA concluded that the project will not have a significant adverse environmental impact across the UK/Netherlands boundary. CF00-00-EB-108-00001 Rev C1 Page 198 of 300

12.0 ENVIRONMENTAL MANAGEMENT 12.1 INTRODUCTION The management of environmental risks associated with the Cygnus development is integral to the decision making process. Environmental hazards are identified at all stages in the development life cycle and risks are assessed and managed via GDF SUEZ E&P UK s Business Management System (BMS). The BMS forms an overarching structure for a large range of company standards and procedure, which includes all of the management system elements for Quality, Health, Safety and Environment (QHSE). This section provides an overview of the key components of the Management System and specific responsibilities relating to the environmental management of the Cygnus development. Effective application through compliance with the BMS during the development of the project will ensure that the GDF SUEZ E&P UK Health, Safety and Environmental (HS&E) Policy and Quality Policy are followed and the company s responsibilities under all relevant regulations are met. 12.2 GDF SUEZ E&P UK S QHSE MANAGEMENT SYSTEM (QHSEMS) 12.2.1 Introduction GDF SUEZ E&P UK has ISO 14001 certification for its QHSE management system (QHSEMS) in both London and Aberdeen offices. In addition the QHSEMS follows the intent of the management system guidelines, ISO 18001 and HS(G)65 complying with both international and UK standards. The QHSEMS applies to all GDF SUEZ E&P UK offshore operated assets and is designed to reduce the impact of company activities on the environment, ensuring the prevention of pollution through careful planning, defined roles and responsibilities, appropriate plans and procedures, robust monitoring and reporting systems and continuous review of performances. Effective implementation of the QHSEMS allows GDF SUEZ E&P UK to operate its business safely and aligned with all relevant UK Legislation. It promotes and helps ensure: Clear assignment of responsibilities. Excellence in environmental, health and safety performance. Sound risk management, planning and decision making. Efficient and cost effective planning and conduct of operations. Legislative compliance throughout all operations. A systematic approach to critical business activities. Continuous improvement. By adopting and implementing a QHSEMS, GDF SUEZ E&P UK will ensure that throughout the project lifecycle there is an ongoing process for environmental risk identification, assessment, mitigation and control. GDF SUEZ E&P UK s QHSEMS is based upon a goal setting philosophy built around a series of performance standards and expectation. It aims to establish a basis of context in which GDF SUEZ E&P UK s employees, contractors, suppliers and other third parties are expected to perform. The scope of the QHSEMS is defined in an EMS manual which provides a linkage of system documents to the various elements of the ISO 14001 standard. The performance and suitability of the management system will be judged through a process of self assessment, by the GDF SUEZ E&P UK environmental management team, and independent verification, through internal and independent audits and reviews. Assessments, findings and recommendations will form the basis for continuous improvement in all GDF SUEZ E&P UK management systems and business processes. 12.2.2 Structure and Goals The QHSEMS provides the framework for managing quality, health, safety and environmental issues throughout the organisation to reflect the operating ethos and practices that GDF SUEZ E&P UK applies in the management of business activity on the UKCS (Figure 12-1). The goals are simply: CF00-00-EB-108-00001 Rev C1 Page 199 of 300

Zero injuries No damage to the environment Consistently deliver our commitments Continually improve our performance by learning from our mistakes Leadership and Commitment from all those involved in GDF SUEZ E&P UK business activities Figure 12-1 : Structure of GDF SUEZ E&P UK s Quality, Health, Safety and Environment Management System 12.2.3 HSE Policy GDF SUEZ E&P UK s HS&E and Quality Policies (see Section 2) define the Company s expectations and commitments to QHSE performance and management, and provide a framework for establishing performance objectives from which annual targets are established. The Policies exemplify GDF SUEZ E&P UK s commitments to protect the environment and is applicable to activities for the Cygnus development. 12.3 ORGANISATION The organisational structure defines the resources and responsibilities required to achieve the Company objectives. All personnel, whether staff or contract, are selected because they have the competence and training to meet those responsibilities and deliver on objectives. It also provides the structure for effective communication both internally and externally. Where internal resources are not available, procedures are applied to ensure effective contractor selection and management. 12.3.1 Key Roles and Responsibilities Managing Director Reports to the Head of GDF SUEZ s global exploration and production unit based at GDF SUEZ corporate head quarters in Paris and is responsible and accountable to the GDF SUEZ E&P UK Board for ensuring that the QHSEMS is established which complies with the Quality and HS&E policies. Creates the organisation and provides resources for implementation of the Quality and HS&E policies. Provides visible and active leadership promoting positive QHSE culture and a shared common understanding of the organisation s vision, values and beliefs. CF00-00-EB-108-00001 Rev C1 Page 200 of 300

Operations Manager Responsible and accountable to the Managing Director for ensuring all operations are undertaken in compliance with Company and industry procedures and guidelines, and with UK Government legislation and regulatory approval. QHSE Manager Responsible and accountable to the Managing Director for ensuring implementation of the QHSEMS. Managers and Supervisors Responsible and accountable through the line management system for communication and implementing the QHSEMS within their respective areas of operation. All Staff and Contractors Responsible and accountable to their Line Manager for complying with the QHSE Management System to achieve the Quality and HS&E policy objectives. Promote a positive QHSE culture by active and visible participation, and consistent adherence to GDF SUEZ E&P UK s goals. Support and encourage open dialogue about QHSE. Establish clear measurable goals, objectives and standards for their team s and their own personal performance. 12.4 CYGNUS DEVELOPMENT MANAGEMENT PROCESS 12.4.1 Legislative Compliance The QHSEMS requires the identification and regular review of legislation and relevant internationally acceptable standards, procedures and specifications for operation and other business activities. 12.4.2 Planning, Resourcing and Contractor Management GDF SUEZ E&P UK implements and maintains a forward-looking QHSE Improvement Plan as a clear commitment towards continuous improvement with clear objectives and targets to be achieved. All hazards and risks associated with planned activities are identified and appropriate control measures established and implemented. Any changes to operations or management are subject to risk review where appropriate. The overriding objective is to ensure risks are maintained at levels that are ALARP. A project specific HS&E plan will be created for the Cygnus development which will define how GDF SUEZ E&P UK will manage HS&E risks and activities. The Plan applies from the concept selection stage through to the project execution phases of the project and: Describes how GDF SUEZ E&P UK will manage the HS&E aspects arising from the project. Presents the key HS&E requirements of the project. Clearly defines HS&E roles and responsibilities. Provides a vehicle for tracking and monitoring. Provides an auditable trail for Project HS&E management. Compliance with relevant HS&E regulations, codes and standards needs to be common across all of the companies that will participate in the development. During construction bridging documents will be in place between the contractors and GDF SUEZ E&P UK. These will describe the management structure and division of responsibilities, the methodology for execution of the work programme and any emergency response procedures. Competency of contractor personnel and contractor s means of achieving a competent workforce for GDF SUEZ E&P UK projects will be identified in the HS&E Plan, assessed in contractor selection and monitored during contractor duration. CF00-00-EB-108-00001 Rev C1 Page 201 of 300

GDF SUEZ E&P UK actively monitor and audit contractor s operational control procedures and their implementation. For example, contractor s proposed method statements, programmes and resources are reviewed during contractor selection (procurement) and all plans, procedures and standards for operational control are reviewed and approved by GDF SUEZ E&P UK. The project will be subject to statutory regulatory control which requires various applications and notifications to be made to nominated governmental bodies for approval of the relevant activities. Effective management of these activities is critical for the success of the project. The current status of these applications and notifications will be regularly monitored to ensure that the necessary consents or notifications are in place when required during the development. The following are the key permits and consents requirements: Environmental Statement (ES) approval. Field Development Plan (FDP) approval. Pipelines Works Authorisation (PWA). Petroleum Operations Notices (PON) approval e.g., PON15C (pipelines), PON15B (drilling), PON15D (platforms). Oil Pollution Emergency Plan (OPEP). It is expected that the mitigation measures identified in the EIA process and reported in this ES will be adopted and bridged into the project specific HS&E plan. 12.4.3 Emergency Preparedness and Response The Cygnus field will have a site specific oil pollution emergency plan (OPEP) that meets the requirements of The Merchant Shipping (Oil Pollution Preparedness, Response Co-operation Convention) Regulations, The Offshore Installations (Emergency Pollution Control) Regulations and the latest guidance issued by the DECC. The plan will cover onshore and offshore response for an incident in the Cygnus field. It will take into consideration both drilling and production activities, including the export of produced fluids. GDF SUEZ E&P UK is an associate member of Oil Spill Response (OSR) who provide clean-up expertise and equipment in the event of hydrocarbon spills. GDF SUEZ E&P UK operates a three-tier response system. The level of response and the strategy adopted depends on the size and characteristics of the spill, the predicted behaviour of the sea, sensitivity of the area and the consequences of the different options available. Tier 1 is a local response, geared at the most frequently anticipated oil spill. Tier 2 is a regional response for a less frequently anticipated oil spill where external resources and assistance in monitoring and clean up will be required. Tier 3 is a national response for very rarely anticipated oil spills of major proportions which will potentially require national and international resources to assist in protecting vulnerable areas and in the clean-up. GDF SUEZ E&P UK have two response organisations: For operations when GDF SUEZ E&P UK are active in the field. For production operations when there is no GDF SUEZ E&P UK presence in the field e.g., subsea template tie-back. In all cases, GDF SUEZ E&P UK will have primacy for oil spill response. In the event of an incident their Incident Management Team (IMT) (located in their Aberdeen office) and the Emergency Management Team (EMT) (located in the London office) will be activated. These teams will handle all response strategies and will mobilise OSR if required. Emergency response plans will be communicated to the workforce and appropriate training exercises carried out and recorded. CF00-00-EB-108-00001 Rev C1 Page 202 of 300

12.5 AUDIT AND REVIEW QHSE performance is monitored on an ongoing basis to ensure compliance with objectives and standards. In particular, emissions and discharges associated with all the phases of the Cygnus development will be monitored regularly. Results will be used to review the environmental performance of the programme against plans and predictions, including predictions made in the ES, and corrective actions will be taken as required. Regular audits will be undertaken to monitor the effective functioning and continued suitability of the QHSE procedures. The objectives and frequency of these audits is determined by the type, level and frequency of activities. Where non-conformance or deficiencies are identified, these are communicated immediately and, where possible, actions taken to rectify them agreed and implemented. Lessons learned and results from the audit and review process are fed back into the system to enable continual improvement of business and management system processes. 12.6 SUMMARY OF ENVIRONMENTAL COMMITMENTS AND MITIGATION MEASURES It is expected that the mitigation measures identified in the EIA process and reported in this ES will be adopted and bridged into GDF SUEZ E&P UK s specific location procedures, the basis of design and the safety case. In addition to the standard best practice mitigation measures, including those that are regulatory requirements, which will be enforced during the project development (see summary in Table 12-1) GDF SUEZ E&P UK are committed to the following: 1) Selecting combustion equipment in line with the requirements of indicative BAT, to minimise emissions and energy consumption. Engineering studies are ongoing to determine the most appropriate operationally and economically feasible option (Section 8.1.4). 2) Inspection and maintenance programmes will be used in line with the requirements of indicative BAT to ensure that combustion equipment is kept and operated in a manner to optimise efficiency and minimise fuel consumption where appropriate (Section 8.2.4). 3) GDF SUEZ E&P UK are currently considering sewage treatment options for Cygnus A. Where possible they will endeavour to follow industry best practice for the region (Section 8.3.4). 4) Precise positioning of rock material by manoeuvring the fall-pipe with an ROV, allowing accurate berm profiles to be built up (Section 8.4.4). 5) Profiles of the pipeline crossings will be designed to minimise snagging potential (Section 10.1.4). 6) Only using sufficient material e.g., concrete mattresses or rock for protection or stabilisation (Section 8.4.4). 7) GDF SUEZ E&P UK will continue to monitor progress of research undertaken by other operators within the SNS in to the potential impact of artificial light on the migration of birds during darkness. Consideration will also be given to the use of alternative artificial lighting systems should research identify that this has a significant beneficial impact without causing a negative effect on safety or operations (Section 8.4.4). 8) The JNCC Statutory nature conservation agency protocol for minimising the risk of injury to marine mammals from piling noise (JNCC 2010a) guidance will be followed. a) Piling vessel will have at least one experienced marine mammal observer (MMO) onboard and will have two if 24 hour operations are expected. b) Piling will not commence during periods of darkness or poor visibility (such as fog) unless MMOs are equipped with night vision binoculars. PAMs will be used if considered appropriate following consultation with the JNCC. c) A pre-piling search will be conducted by the MMO. Piling will not commence if marine mammals detected within 500m of the activity or until 20 minutes after the last visual detection. CF00-00-EB-108-00001 Rev C1 Page 203 of 300

d) Slow start up i.e., gradual ramping up of piling power, will be used for piling to ensure that any mammals outside the observation zone will have sufficient time to leave the area. The soft start up duration will not be less than 20 minutes. e) If a marine mammal comes within 500m of the piling during the soft start then, if possible, the piling will cease or at the least the power will not be ramped up further until the marine mammal has left the zone and there has been no further detection for at least 20 minutes. f) If there is a break in the piling operations for a period of greater than 10 minutes a pre-piling search and soft start procedure will be repeated. g) If deemed appropriate by the DECC, GDF SUEZ E&P UK will apply for a European Protected Species (EPS) licence. Activities will be undertaken in accordance with any conditions attached to the EPS licence. h) GDF SUEZ E&P UK will comply with the reporting requirements outlined in the JNCC protocol. 9) During award of the contracts for any support vessels, DP vessels or self propelled barges, GDF SUEZ E&P UK will review the use of ducted propellers including Kort nozzles and Azimuth thrusters. Where possible vessels without these propellers will be preferentially selected, however if this is not feasible, GDF SUEZ E&P UK will consult with the JNCC concerning the use of MMOs. It is possible that the JNCC will further refine their advice concerning this issue and GDF SUEZ E&P UK will continue to consult with them in order to respond to any appropriate changes in best practice (Section 9.5.5.2). 10) GDF SUEZ E&P UK will consider using a guard vessel to protect the pipelines for the period between being laid on the seabed and being trenched. The vessel will liaise with fishing vessels in the area to ensure that they are aware of the pipeline and risks involved with trawling over it. It has not yet been determined whether the pipeline will be buried mechanically or naturally. This decision will include assessment of the potential for snagging of fishing gear whilst the pipeline remains unburied (Section 10.1.4). 11) Construction of the pipeline crossings over the Cavendish gas export pipeline and Tyne to Trent infield line to will be undertaken under crossing agreements established with RWE Dea UK Ltd and Perenco. GDF SUEZ E&P UK will comply with any conditions attached to these agreements. In addition, safety precautions will include as a minimum a separation distance of 50m between the trenching plough and the buried pipelines (Section 10.3.4). 12) The British Marine Aggregate Producers Association (BMAPA) protocol will be followed should any artefacts be discovered on the seabed which could potentially be of archaeological significance (Section 10.4.4). It is expected that the mitigation measures will be adopted into the project specific HS&E plan which will define how GDF SUEZ E&P UK will manage HS&E risks and activities and how mitigation measures will be implemented. The plan will be regularly monitored to ensure that the necessary steps have been taken to implement measures i.e., commitments are incorporated into key permits and consents. Where relevant, Contractors will be made aware of commitments that they will be responsible for and GDF SUEZ E&P UK will monitor through auditing what processes and procedures the Contractor(s) has in place to ensure measures are implemented. CF00-00-EB-108-00001 Rev C1 Page 204 of 300

Table 12-1 : Summary of all Cygnus standard mitigation measures and regulatory requirements Mitigating atmospheric emissions Ensure efficient operations by keeping all power generation equipment well maintained. Use of low sulphur content fuels where possible. Flaring and venting will be within permitted levels as outlined in the relevant permits and will be kept to the minimum required for safe operations. High efficiency burners will be used for flaring. Emissions from power generation will be managed under the appropriate permits for the development. Energy efficiency will be investigated as part of permitting (e.g., PPC permit, GHG permit, EU ETS). GDF SUEZ E&P UK will check whether contractors have ISO 14001. Chemical and produced water management Selections of chemicals will be made in accordance with the CEFAS ranked list, where chemicals ranked as lower potential hazards are preferentially chosen. Only chemicals permitted through the relevant Offshore Chemicals Regulations chemical permit (i.e., PON15B, C or D) and that have been subject to a risk assessment will be discharged. Chemical use will be monitored daily during construction to allow more refined and efficient use. Chemical use and discharge will be minimised where operationally possible by measures such as recycling. Cement dead volumes in mixing pits will be minimised by using a cement liquid additive system to calculate the volume of fluid required for the job. Produced water discharge will be closely monitored to ensure that all contaminants are at an acceptable level. Oil in water, chemical, aromatic and radionuclide concentrations will all be reported via the appropriate permit i.e., PON15D or OPPC. All oil discharges will be covered by an approved OPPC permit. Sections will be drilled with weighted fluids to prevent reservoir hydrocarbon intrusion into the wellbore. Hydrocarbon and chemical spill prevention and management A location specific approved OPEP will be in place for the development that covers drilling and production. The OPEP will detail all emergency procedures that will be in place to minimise the impact of any spill. Accidental spills will be kept to a minimum through good practice codes, collision avoidance and fuel handling and transfer procedures. The positioning of bunds / drip trays will be considered during detailed design. Pipeline connections will be minimised and welds maximised. Regular pipeline inspections will be carried out in line with the industry standard inspection frequencies. Chemical protection will be provided to prevent pipeline corrosion. All staff and contractors will be required to undertake training and maintain good housekeeping standards. CF00-00-EB-108-00001 Rev C1 Page 205 of 300

Management controls will be in place to reduce accidental events and eliminate bunkering spills. For example: Only bunkering during day light and in good weather, where possible. If during winter this is not possible transfers will be assessed to identify potential risks and any risks mitigated to acceptable levels. A continuous watch will be maintained during offloading. Fuel will be transferred between vessels via hoses that will be equipped with a one way valve. All bunkering operations will be conducted in strict compliance to contractor s procedures. These procedures will be referenced in a combined GDF SUEZ E&P UK Management System Bridging Document, which will be circulated to all appropriate personnel. The management of bunkering operations will be discussed with the contractor s team prior to commencement of operations. Third party contractors will have their own procedures in place to mitigate accidents. During the construction phase, the contractors owning each of the various construction vessels being used will retain individual responsibility for spills and maintain approved shipboard oil pollution emergency plans (SOPEP). GDF SUEZ E&P UK has access to Tier 1, 2 and 3 oil spill response capabilities through Oil Spill Response (OSR) and is also a member of OSPRAG. Mitigating collision risk and hazard avoidance A 500m safety exclusion zone around the drilling rig(s), platforms and subsea infrastructure will be enforced. To reduce the likelihood of collision, the drilling rig, platforms and construction vessels will be appropriately lit and sound warnings will be broadcast in poor visibility. Via the Kingfisher Fortnightly Bulletins, Notices to Mariners and, where appropriate, VHF radio broadcasts users of the sea will be notified of: The presence of exclusion zones. The presence and intended movements of construction vessels. The presence of new structures, and areas of mattressing or rock material. Footprints on the seabed will be minimised through careful design and where possible, by positioning drilling rig legs in existing footprints on return to the sites. Opportunities to reduce the number of rig moves are currently being explored. Vessel operating procedures should ensure anchor drag is minimised. Trench profiles will be designed to minimise the creation of berms. Subsea structures will be designed to be fishing friendly with no snag points. A debris clearance survey will be undertaken at the end of each construction period, ensuring that any significant objects are removed. For any dropped objects that cannot be removed, GDF SUEZ E&P UK will submit a PON2 form to the DECC, MCA and NFFO to notify other sea users of the position of the obstruction. Pipeline integrity will be ensured by pre-commissioning testing. GDF SUEZ E&P UK will have a collision risk management plan in place for the proposed development, compliant with IMO standard requirements. All vessels will follow the IMO Standards and will be properly marked. The pipelay vessels will have a National Federation of Fishermen's Organisations (NFFO) approved Fisheries Liaison Officer (FLO) onboard who will regularly communicate coordinates to the fishing industry. A dropped objects plan will be developed to address risk of dropping objects during construction and operations. CF00-00-EB-108-00001 Rev C1 Page 206 of 300

Waste management Every vessel will have and implement a written waste management plan compliant with the International Convention for the Prevention of Pollution from Ships (1973/1978) (Marpol 73/78) and its Annexes. As per Regulation 9 (Annex V, 1995) all vessels over 400 tonnes will have and maintain a Garbage Record Book. The plan will establish designated waste storage areas and implementation of the plan will ensure all waste is contained and stored away from open drains. All liquid waste will be stored with secondary containment Paper and food wastes will be disposed of in a manner that is compliant with the relevant regulations. No plastics nor plastic containing material, will be disposed at sea, regardless of location. Solid wastes will be compacted where possible and stored for appropriate disposal ashore. All project associated vessels will work to International Maritime Organisation (IMO) standards. Non-hazardous and hazardous area drains will be diverted to the oil / water separator, where oil will be removed. CF00-00-EB-108-00001 Rev C1 Page 207 of 300

13.0 CONCLUSIONS 13.1 THE PROJECT The Cygnus field development is a medium sized gas development located within the already extensively developed SNS gas basin. The development lies approximately 155km north-east of the north Norfolk (UK) coastline, 35km west of the UK/Netherlands median line and within the Dogger Bank csac. The construction phase of the development is likely to be executed over three and a half years and the field will produce for up to 35 years. 13.2 EXISTING ENVIRONMENT Existing environmental conditions were established through an environmental baseline and habitat assessment survey, which revealed that: The benthic community is typical of a moderately dynamic sandy substrate in the SNS with a biological community dominated by polychaetes, consistent with existing surveys in the region No habitats or species of conservation significance under the UK s Offshore Marine Conservation (Natural Habitats, &c) (Amendment) regulations 2010 were observed in the project area Metocean conditions in the region of the project were also identified as supporting a dilution and dispersion regime (i.e., winds are sufficient to disperse atmospheric emissions while tidal currents will refresh the water column within one hour and are sufficient to disperse drill cuttings or sediment piles on the seabed) rapidly reducing the impact significance of emissions to air, water and seabed. 13.3 POTENTIAL IMPACTS All potential effects of the project on the environment were identified and quantified by reviewing the existing environmental conditions within the development footprint (and surrounding environment) and identifying and evaluating the significance of any impacts associated with the development on these conditions. It should be noted that the majority of effects were assessed as having no impact (impact will not be detectable), no significant impact (impact will not be detectable beyond the immediate vicinity and duration of the activity) or a low impact (impact will not be detectable beyond the 500m exclusion zone or beyond two years), on the receiving environment. 13.3.1 Construction Impacts The EIA concluded that all construction activities would have either no impact or a low impact on environmental receptors. No impacts of moderate or major significance were identified. The following conclusions were reached: Atmospheric emissions will be generated from construction vessels and well clean-up and testing. It is predicted that concentrations of NOX and SO2 will be below European Commission threshold values to protect human health and the environment within 500m of the discharge point. The CO2 emissions represent approximately 0.8% of the total UKCS emissions of greenhouse gases, which is standard for a development of this size. Water quality may show a temporary decline as a result of chemical and other discharges during construction but this will restricted to the immediate vicinity of the discharge point and will toxic impacts are not expected. Approximately 1.46km 2 of seabed will be disturbed by construction activities. It is expected that physical disturbance will be unnoticeable against background levels within a year of cessation of construction activities. Benthic communities in the footprint are expected to recover to pre-impact levels within three months to two years. Comparison of pre-drilling and post-drilling surveys indicates that there will be no evidence of drill cuttings within a few months, and although there may be elevated levels of contaminants within sediments, the classification will not change from unpolluted to polluted. CF00-00-EB-108-00001 Rev C1 Page 208 of 300

There is a negligible risk of an offence occurring under the HR and OMR as a consequence of subsea noise generated from pile driving. The integrity of the Dogger Bank csac will not be affected by the project. 13.3.2 Production Impacts The Cygnus field development will have the following impacts on the environment: 2,542 tonnes of CO2 will be emitted from power generation equipment per annum. XX tonnes of condensate in produced water will be discharged per annum. All produced water discharges will be compliant with OSPAR recommendation 2005/03 i.e., oil in water concentrations <30mgl -1. Mitigation measures have been proposed to reduce the impacts on environmental receptors. The relevant UK Regulatory consents will be applied for and all emissions will be monitored within the conditions outlined on the permits. The EIA concluded that these impacts will not cause a residual impact on environmental receptors. 13.3.3 Accidental Events Three worst case scenarios were identified that could result in a substantial spill of condensate or diesel to the marine environment; loss of well control, loss of rig inventory; and failure of the export pipeline. Oil spill modelling was undertaken to inform the EIA which indicated that condensate and diesel will evaporate and disperse within eight hours. It is highly unlikely that hydrocarbons would beach on the coastline or cross any international boundary. Therefore, the EIA concluded that the potential impacts on environmental receptors were of low significance. Mitigation measures that GDF SUEZ E&P UK will put in place to minimise or eliminate identified impacts and been outlined and will be managed through the oil pollution emergency plan for the development and well control procedures. 13.3.4 Cumulative and Transboundary Impacts Consideration has been given to the potential for cumulative impacts from both existing and planned gas developments in the region and the combination of impacts from other industries with the Cygnus development. The project will have a small contribution to increased subsea noise levels during pile driving, the amount of rock material on the seabed and the decrease in area available for commercial fishing and navigation. GDF SUEZ E&P UK are in continued consultation with the operators of the Forewind wind farm development to ensure that cumulative impacts are managed and mitigated where appropriate. Overall, the EIA concluded that the significance of cumulative impacts will be low. The worst-case scenario oil spill modelling conducted to inform the EIA indicates that condensate / diesel will travel 2 to 3 km from the spill location, meaning the leading edge of the spill will still be 32km from the closest international boundary. In addition, cuttings dispersal modelling for the Cygnus exploration well (using PROTEUS) and similar modelling of other SNS wells indicate that drill cuttings become indistinguishable from sediments within 4.6km of the well location. These project aspects and all others with a potential to interact with environmental receptors have been fully considered and mitigated against, and therefore the EIA concluded that the project will not have a significant adverse environmental impact across the UK/Netherlands boundary. 13.3.5 Decommissioning It is anticipated that operations will cease between 2024 and 2038 depending on reservoir performance, economic variable and the potential for tie-back to the facilities from other developments. The arrangements for decommissioning the field will be developed in accordance with UK legislation and international agreements in force at the end of field life. Current decommissioning requirements have been taken into consideration in project design. The potential impacts from decommissioning have not been considered in this EIA as they will be the subject of a separate EIA submitted prior to decommissioning. CF00-00-EB-108-00001 Rev C1 Page 209 of 300

13.4 ENVIRONMENTAL MANAGEMENT The GDF SUEZ E&P UK BMS, QHSEMS and corporate policies provide a fit for purpose framework to implement the mitigation measures proposed in this ES. The QHSEMS also provides adequate control and bridging arrangements for GDF SUEZ E&P UK to ensure that the contractors implement these mitigation measures. During the construction and production operations, a set of permits and consents will be obtained from the regulatory bodies. Any conditions attached to these will also be fed into the QHSEMS to ensure compliance. QHSEMS performance will be regularly benchmarked against recommendations through independent verifications, by both internal and independent external audits and reviews. With mitigation measures in place, the Cygnus field development will have a negligible to low impact on the environment. CF00-00-EB-108-00001 Rev C1 Page 210 of 300

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Appendix 1 - Key Policy, Law and Guidelines 1.0 INSTITUTIONAL POLICY AND REGULATORY FRAMEWORKS This Appendix supports Section 2 of the ES and provides further details on the main policies, laws and guidelines relevant to this project that were considered when undertaking the EIA. 1.1 RELEVANT POLICY AND GUIDELINES Energy White Paper 2007 and the UK Carbon Transition Plan 2009 Sets out the UK Governments international and domestic energy strategy to respond to the changing circumstances in global energy markets and to address the long term energy challenges the country faces (DTI 2007, HM Government 2009). Marine Policy Statement UK Government and devolved administrations have worked together to set out a number of high level marine objectives which articulate the outcomes they are seeking for the UK marine area as a whole. Their vision is to achieve clean, healthy, safe, productive and biologically diverse oceans and seas. The Department for Environment, Food and Rural Affairs (Defra) are responsible for developing this strategy. It will set out the general environmental and human considerations that need to be taken into account in marine planning. Consultation on the Statement and supporting documents has been ongoing since 2008 and the Marine Policy Statement was adopted in March 2011. UK Biodiversity Action Plan (UK BAP) The UK BAP is the UK Government s response to the Convention on Biological Diversity (CBD) (1992). It describes the UK s biological resources and provides detailed plans for the protection of these resources. In 2007 the UK BAP list was reviewed and now includes 1,150 species and 65 habitats. Action plans, which set out priorities, actions, targets and reporting targets, have been created for 382 species and 45 habitats. 1.2 INTERNATIONAL CONVENTIONS, EC AND UK LAWS AND REGULATIONS International Conventions Convention for the Protection of the Marine Environment of the North East Atlantic (Oslo Paris Convention (OSPAR) Convention) 1992 main legislative instrument regulating international cooperation. It concentrates on provisions to protect the marine environment through the use of best available techniques, best environmental practice and where appropriate clean technologies. The precautionary principle concept also features prominently. The convention regulates European standards on the offshore oil and gas industry, marine biodiversity and baseline monitoring of environmental conditions (OGUK 2008). As a signatory to the Convention, the UK, and therefore the UK oil and gas industry and this project, are governed by the legislative framework the Convention enforces. For example, the OSPAR convention prohibits the discharge of oil based mud (OBM), which determines how drill mud and/or cuttings are managed during a drilling operation. Convention on Biological Diversity (CBD) 1992 this international treaty sets out commitments for maintaining ecological biodiversity as the world develops. The Convention establishes three main goals: the conservation of biological diversity, the sustainable use of its components, and the fair and equitable sharing of the benefits from the use of genetic resources. UK Government has reacted to the commitments of the Convention by establishing the UK BAP discussed in Section 2.1. United Nations Framework Convention on Climate Change (1994) - The Convention sets an overall framework for intergovernmental efforts to tackle the challenge posed by climate change. It recognises that the climate system is a shared resource whose stability can be affected by industrial and other emissions of carbon dioxide and other greenhouse gases. Under the Convention the Government is committed to gather and share information on greenhouse gas emissions and launch national strategies for addressing greenhouse gas emissions (UNFCCC 2008). The convention has also influenced EC and UK legislation, being CF00-00-EB-108-00001 Rev C1 Page 219 of 300

pivotal in the establishment of the EC Council Directive 2003/87/EC and the UK Greenhouse Gas Emissions Trading Scheme Regulations, discussed in Sections 2.2.2 and 2.2.3. Convention on Environmental Impact Assessment in a Transboundary Context (Espoo) 1991 The Espoo Convention sets out the obligations of Parties to assess the environmental impact of certain activities at an early stage of planning. It also lays down a general obligation to States to notify and consult each other on all major projects unde r consideration that are likely to have a significant adverse environmental impact across boundaries. The Convention was adopted in 1991 and entered into force in 1997. EC Law The European Commission issues directives, regulations, decisions, opinions and recommendations (see glossary for definitions) to member states. The above cover all aspects of society from culture, technology and human rights to the environment, wildlife and nature conservation. The development will be subject to a wide range of Directives and Regulations as they are implemented in UK law. A number of the key Directives are listed below: Council Directive 97/11/EC (EIA Directive) Amended Directive 85/337/EC on the assessment of the effects of certain public and private projects on the environment. Requires environmental assessments to be carried out for certain types of offshore oil and gas activities. Council Directive 2003/35/EC (Public Participation Directive) provides for public participation in respect of the drawing up of certain plans and programmes relating to the environment and amending with regard to public participation and access to justice. Council Directive 2001/42/EC (SEA Directive) The purpose of the Strategic Environmental Assessment (SEA) Directive is to ensure that environmental consequences of certain plans and programmes are identified and assessed during their preparation and before their adoption. This will mean that environmental assessments carried out for individual projects will be able to take advantage of additional data and information on the regional impacts of the oil and gas industry. Council Directive 92/43/EC (Habitats Directive) Directive on the conservation of natural habitats and wild fauna and flora. The Directive introduces a range of measures to protect 189 habitats and 788 species listed in the Annexes. Each member state is also required to prepare and propose a national list of sites to be adopted as Special Areas of Conservation (SACs). Council Directive 79/409/EC (Birds Directive) The Directive provides a framework for the conservation and management of, and human interactions with, wild birds in Europe. Like the Habitats Directive it introduces a range of measures to maintain the favourable conservation status of all wild bird species across their distributional range and allows for the establishment of Special Protection Areas (SPAs) for rare or vulnerable species. Council Directive 2008/1/EC (Integrated Pollution Prevention and Control (IPPC) Directive) replaces Directive 96/61/EC and aims to prevent and control emissions to air, water and soil from industrial installations. The directive aims to increase the use of best available techniques (BATs), to ensure a higher level of environmental protection. Council Directive 2003/87/EC (EU Emissions Trading Scheme (EU ETS) Directive) The Directive establishes a scheme for greenhouse gas emissions allowance trading within the European Community. The Directive requires that member states establish national allocation plans for emissions. Council Regulation 1907/2006 Registration, Evaluation, Authorisation and Restriction of Chemicals (REACH) - Applies to substances manufactured or imported into the EU in quantities of 1 tonne or more per year. Aims to protect human health and the environment from chemical use. OSPAR Recommendation 2010/5 on the assessment of environmental impacts on threatened and/or declining species Requires that Contracting Parties to OSPAR take into consideration the relevant species and habitats on the OSPAR List of threatened and/or declining species and habitats when assessments of environmental impacts of human activities that may affect the marine environment of the OSPAR maritime area are prepared. CF00-00-EB-108-00001 Rev C1 Page 220 of 300

UK Law Although not an exhaustive list, the main UK regulations applying to the project are listed below: Petroleum Act 1998 Requires all offshore oil and gas developments to apply for consent to undertake the project. Consent is issued by the Secretary of State (SoS) and in addition to giving consent to construct the development authorises the owners to operate the development. Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) (Amendment) Regulations 2007 amend the 1999 regulations of the same name. The regulations implement the EC EIA Directive and Public Participation Directive; requiring an ES to be submitted for offshore oil and gas projects and public participation in the consent process. Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001 (amended in 2007) The regulations apply the Habitats Directive and Birds Directive in relation to oil and gas projects on the UKCS. Offshore Marine Conservation (Natural Habitats, &c.) Regulations 2007 (as amended in 2009 and 2010) These regulations apply in the offshore area of the UK and protect marine species and wild birds through a number of offences that aim to prevent environmentally damaging activities. It is now an offence under the Regulations to deliberately disturb wild animals of a European Protected Species. The regulations also implement in the UK the EC Directives 92/43/EC (Habitats Directive) and 79/409/EC (Birds Directive). Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2011 The regulations are designed to encourage operators to reduce the quantities of hydrocarbons discharged during the course of offshore operations. Offshore Chemical (Amendment) Regulations 2011 Requires all offshore operators using and/or discharging chemicals to apply for a chemical permit. With respect to the project this will take the form of Petroleum Operations Notices (PONs) for the well interventions / completions (PON15F) and pipeline (PON15C) which will be submitted to the Department of Energy and Climate Change (DECC) in advance of operations. Merchant Shipping (Oil Pollution Preparedness, Response Co-operation Convention) Regulations 1998 Under these regulations operators of offshore oil and gas installations and pipelines must have an approved oil pollution emergency plan (OPEP) setting out arrangements for responding to incidents which cause or may cause marine pollution by oil, with a view to preventing such pollution or reducing or minimising its effect. The Offshore Installations (Emergency Pollution Control) Regulations 2002 The Regulations give the UK Government powers to intervene in the event of an incident or accident involving an offshore installation where there is, or may be risk of, significant pollution, or where the operator is failing or has failed to implement effective control and preventative operations. Marine and Coastal Access Act (MCAA) 2009 The Act seeks to improve management and increase protection of the marine environment. It is a large Act that covers a multitude of provisions. Amongst other things it establishes a new Marine Management Organisation, to produce marine plans, administer marine environmental licensing, enforce environmental protection law and manage marine fisheries, and introduces new mechanisms for the designation of marine conservation zones. Energy Act 2008 The provisions of the Coast Protection Act relating to navigation considerations regarding the oil and gas industry were transferred to the Energy Act in April 2011 by the MCAA. The change introduces a formal application process linked the environmental regime for consent to locate fixed infrastructure e.g., pipelines, platforms, wellheads, drilling rigs etc. It will also apply to some vessel activities if the vessel is physically connected to the seabed that could constrain their ability to navigate e.g., drill ships and intervention vessels. The Merchant Shipping (Prevention of Pollution by Sewage and Garbage from Ships) Regulations 2008 The regulations implement in the UK the requirements of MARPOL 73/78 Annex IV. It should be noted that MARPOL also defines a ship to include fixed and or floating platforms and these are required where appropriate to comply with the requirements similar to those set out of vessels. CF00-00-EB-108-00001 Rev C1 Page 221 of 300

The Greenhouse Gas Emissions Trading Scheme Regulation 2005 (as amended) provide a framework for a greenhouse gas emissions trading scheme and implement EC Directive 2003/87/EC. Any installation with combustion plant that on its own or in aggregate with any other combustion plant has a rated thermal input exceeding 20MW(th) is required to be registered under the EU ETS. The Offshore Combustion Installations (Prevention and Control of Pollution) (Amendment) Regulations 2007 The regulations implement EC Directive 96/61/EC and apply to combustion installations located on offshore oil and gas platforms where an item of combustion plant on its own, or together with any other combustion plant installed on a platform, has a rated thermal input exceeding 50MW(th). CF00-00-EB-108-00001 Rev C1 Page 222 of 300

Appendix 2 - Environmental Impact Assessment 2.1 INTERACTION MATRIX Environmental Receptor Physical Biological Human A B C D E F G H I J K L M N Construction Project Activity Air Quality Climate Change Water resources Seabed conditions Physical presence and movement of transportation Drilling of wells Installation of infrastructure Production Presence of platform Physical presence and movement of transportation Power generation Gas venting Flaring Produced water Maintenance of platforms, pipelines and wells Accidental Events Spill of chemicals or hydrocarbons (<1 tonne) Spill of chemicals or hydrocarbons (>1 tonne) Overboard loss of equipment or waste Plankton Benthic ecology Fish and shellfish Seabirds Marine mammals Protected Sites and Species Commercial fishing Shipping and Navigation Archaeology Other Marine Users CF00-00-EB-108-00001 Rev C1 Page 223 of 300

2.2 CONSTRUCTION Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section A Air Quality A-1 Physical presence and movement of transportation Exhaust gas emissions Localised deterioration in air quality Definite Site Specific Short-term Ensure all machinery is maintained. Use of low sulphur content fuels where possible. Check whether contractors have ISO 14001. Atmospheric emissions from exhaust gases will be small (Section 6.1.1.1). Modelling indicates that pollutants (such as NO x and SO x) will be dispersed and diluted to levels below health and environmental guidelines within 500m of the discharge point. See Section 8.1.5 for full discussion. N - - - - 8.1.5 A-2 Drilling of wells Flaring of gas Localised deterioration in air quality B Climate Change B-1 Physical presence and movement of transportation Exhaust gas emissions Loading of greenhouse gases e.g., CO 2, CH 4 Definite Site Specific Unlikely Wider Environment Short-term Short-Term Flaring will be within permitted levels as outlined in the relevant permits and will be kept to the minimum required for safe operations. Ensure all machinery is maintained. Use of low sulphur content fuels where possible. Check whether contractors have ISO 14001. Each of the ten development wells will be flared for a maximum of 24 hours to clean up and test the reservoir. There is the potential that three of the wells will be flared for a further 9 days as an extended well test. The atmospheric emissions are presented in Section 6.1.1.2. Flaring is a standard oil and gas industry activity and is always carried out within permitted levels. Modelling indicates that concentrations of NO x and SO x will be diluted to less than 1µgm -3, below health and environmental guidelines within 500m of the discharge point. See Section 8.1.5 for full discussion. The construction phase not including well testing will emit up to around 31,000 tonnes of CO 2 per year which is 0.6% of the annual offshore emissions for similar activities in 2009 (Section 8.2.5). This is a relatively small contributor to annual UK emissions, and is typical for a gas development of this size. N - - - - N - - - - 8.1.5 8.2.5 B-2 Drilling of wells Flaring of gas Loading of greenhouse gases e.g., CO 2, CH 4 Unlikely Wider Environment Short-Term Flaring will be within permitted levels as outlined in the relevant permits and will be kept to the minimum required for safe operations. Each of the ten development wells will be tested for a maximum of 24 hours. There is the potential that three of the wells will be flared for a further 9 days as an extended well test. The atmospheric emissions are presented in Section 6.1.1.2. Assuming that four wells will be tested per year, including one extended well test, approximately 25,843 tonnes of CO 2 will be emitted which is approximately 15.3% of the total UK annual emissions from well testing. This figure is standard for UK O&G offshore developments and therefore no residual impact on climate change is expected. N - - - - 8.2.5 CF00-00-EB-108-00001 Rev C1 Page 224 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section C Water Resources C-1 Physical presence and movement of transportation C-2 Physical presence and movement of transportation Discharge of sewage, grey water, food waste & drainage water Use of thrusters in shallow water Deterioration in water quality Increased suspended sediment loads & turbidity Definite Definite Site Specific Site Specific Medium Short-term Short-term All project associated vessels will have It is likely that much of the sewage and grey water produced from and implement a written waste construction vessels will be retained onboard. However, for the management plan compliant with the purposes of the assessment it has been assumed that all vessels could International Convention for the potentially discharge sewage and grey water, generating a maximum Prevention of Pollution from Ships 44,300m 3 of sewage and grey water during the entire construction (1973/1978) (Marpol 73/78) and its period (Section 6.1.2.3). Although much of the project area is relatively Annexes. shallow, it is considered that given the current speeds (average of Paper and food wastes will be 0.3ms -1 ), the refreshment rates in the area (<1hr) and the relatively disposed of in a manner that is small cumulative volumes of discharges, any discharge will be quickly compliant with the relevant dispersed and the marine environment will be able to rapidly assimilate regulations. Solid wastes will be the discharges and deal with them through natural bacterial action it is compacted where possible and stored likely that any degradation in water quality will be transient (limited to a for appropriate disposal ashore. few hours after the discharge) and there will be no residual impact on water quality Selections of chemicals will be made in accordance with the CEFAS ranked list, where chemicals ranked as lower potential hazards are preferentially chosen. Sewage discharge from the rig will undergo treatment prior to release. Discharges from construction vessels will undergo the level of treatment required by shipping regulations. All project associated vessels will work to IMO standards. None envisaged. The shallowest point along the pipeline route is 15.99m (Senergy 2011a). If a DP vessel is used, the maximum depth that thrusters will have an impact on the water column is approximately 14m from the sea surface. Below this depth the effects are generally not discernible from natural currents and wave orbital motions. However, the short distance to the seabed (2m) at the shallowest point may mean that seabed sediments are disturbed, increasing sediment loads. It is considered the disturbance will be similar to storm events. The DP vessel will only be active along the pipeline routes for a maximum of 40 days and any disturbance will be transitory, therefore no residual impact on water quality from suspended sediments is anticipated. N - - - - N - - - - 8.3.5 8.3.5 CF00-00-EB-108-00001 Rev C1 Page 225 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section C-3 Drilling of wells Discharge of reservoir hydrocarbons Deterioration in water quality Definite Site Specific Short-term All oil discharges will be covered by an approved OPPC permit. Sections will be drilled with weighted fluids to prevent reservoir hydrocarbon intrusion into the wellbore. The wells will target a dry gas reservoir where the condensate-gas ratio is N - - - - 1.9bbl/mmscf (Section 6.4.2.1). Considering the mitigation measures, contamination of drilling fluids discharged to sea by condensate is not expected. 8.3.5 C-4 Drilling of wells Installation of infrastructure Discharge of chemicals (including WBM) Deterioration in water quality Definite Site Specific Short-term Selection of chemicals will be made in accordance with the CEFAS ranked list, where chemicals ranked as lower potential hazards are preferentially chosen. Only chemicals permitted through the relevant Offshore Chemicals Regulations chemical permit (i.e., PON15B, C or D) and that have been subject to a risk assessment will be discharged. Chemical use will be monitored daily during construction to allow more refined and efficient use. Chemical use and discharge will be minimised where operationally possible by measures such as recycling. Cement dead volumes in mixing pits will be minimised by using a cement liquid additive system to calculate the volume of fluid required for the job. All chemical discharges will be risk assessed and within permitted levels. Currents in the project area are of average strength for the SNS (0.3ms - 1 ) and combined with wave action will disperse and dilute chemical discharges. Currents will refresh a 500m column of water surrounding the discharge location within one hour (Section 8.3.5). No residual impact on water quality is expected from chemical discharges N - - - - 8.3.5 CF00-00-EB-108-00001 Rev C1 Page 226 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section C-6 Installation of infrastructure Trenching Increased suspended sediment loads & turbidity Definite Site Specific Medium Short-term Pipeline route will be optimised Assuming the V shaped trench has a maximum trench width of 6m and Y depth of 3m, the maximum volume of sediments disturbed by trenching is 9,000m 3 km -1. Sediment particle analysis indicates that sediments are predominantly sand sized material which will quickly fall out of suspension due to its weight. Silt sized material (which constitutes less than 2% for the first half of the pipeline route and between 3.8 to 9.7% in the last half of the route) is likely to remain in suspension for longer, temporarily increasing the suspended sediment loads in the water column. However, the impact occurs against a background of seabed disturbance as a result of wave and tidal activity, is localised and very short-term (trenching is scheduled to take approximately forty days to complete). - - 8.3.5 C-7 Installation of infrastructure Concrete mattressing and rock material Increased suspended sediment loads & turbidity Definite Site Specific Short-term None envisaged A maximum of 36,600m 2 of seabed will be covered by concrete mattresses and rock placement. As the material is placed on the seabed, sediments will be displaced and suspended. Sediment particle analysis indicates that sediments are predominantly sand, which will quickly fall out of suspension due to its weight. The silt content is very low and there is unlikely to be a significant increase in suspended sediment loads in the water column. In addition, the impact occurs against a background of seabed disturbance as a result of wave and tidal activity. The impact will be localised and very short-term in terms of effects on water quality. N - - - - 8.3.5 C-8 Physical presence and movement of transportation Installation of infrastructure Positioning structure on seabed e.g., jack-up legs, platforms, other subsea structures, and anchors Increased suspended sediment loads and turbidity Definite Site Specific Short-term Vessel operating procedures should ensure anchor drag is minimised. The jack-up rig and accommodation vessel spud cans, the platforms and N - - - - other subsea structures and the anchor lay barge and heavy lift vessel anchors will have a combined seabed footprint of 1.46km 2. Sediments may be displaced and suspended during these operations. Sediment particle analysis indicates that sediments are predominantly sand, which will quickly fall out of suspension due to its weight. The silt content is very low and there is unlikely to be a significant increase in suspended sediment loads in the water column. In addition, the impact occurs against a background of seabed disturbance as a result of wave and tidal activity. The impact will be localised and very short-term in terms of effects on water quality. 8.3.5 CF00-00-EB-108-00001 Rev C1 Page 227 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section D Seabed Conditions D-1 Physical presence and movement of transportation Installation of infrastructure D-2 Physical presence and movement of transportation Positioning structure on seabed e.g., jack-up legs, platforms, other subsea structures, and anchors Use of thrusters in shallow water Compaction / disturbance of surface sediments. Change in seabed topography Change / disturbance of surface sediments Definite Definite Site Specific Site Specific Medium Medium-term Short-term Footprints on the seabed will be minimised through careful design and where possible, by positioning drilling rig legs in existing footprints on return to the sites. Opportunities to reduce the number of rig moves are currently being explored. Opportunities to reduce the number of rig moves are currently being explored. Vessel operating procedures should ensure anchor drag is minimised. None envisaged. The jack-up rig and accommodation vessel spud cans, the platforms and N - - - - other subsea structures and the anchor lay barge and heavy lift vessel anchors will have a combined seabed footprint of 1.46km 2. The platforms and subsea structures will cover a small area of seabed for the duration of the development field life. Whilst the impacts will be medium term they will be localised and are considered to be negligible. The jack-up rig and accommodation vessel spud cans will leave depressions in the seabed on their removal which will have a minor impact on the seabed topography. However, the impacts will be localised and occur against a background of seabed disturbance as a result of wave and tidal activity. As no depressions are evident in SSS images from the exploration well site (drilled in late 2005/early 2006) it suggests that sediments in the immediate vicinity of Cygnus A drilling location are mobile enough to infill any depressions created and any impact will be of a short-duration. Anchor mounds associated with the use of anchors by the heavy lift vessel and anchor lay barge if used, will also be localised and research in the SNS (BMT Cordah Ltd 2006) indicates they are likely to have been dispersed within a month. The shallowest point along the pipeline route is 15.99m (Senergy 2011a). If a DP vessel is used, the maximum depth that thrusters will have an impact on the water column is approximately 14m from the sea surface. Below this depth the effects are generally not discernible from natural currents and wave orbital motions. However, the short distance to the seabed (2m) at the shallowest point may mean that seabed sediments are disturbed, increasing sediment loads. It is considered the disturbance will be similar to storm events. The DP vessel will only be active along the pipeline routes for a maximum of 40 days and any disturbance will be transitory, therefore no residual impact on disturbance of surface sediments is anticipated. N - - - - 8.4.5 8.4.5 CF00-00-EB-108-00001 Rev C1 Page 228 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect D-3 Drilling of wells Installation of infrastructure D-4 Drillings of wells Discharge of chemicals (including WBM) Discharge of cuttings D-5 Drilling of wells Discharge of reservoir hydrocarbons Potential Impact Sediment contamination Change in seabed topography Sediment contamination Likelihood Possible Definite Unlikely Spatial extent Site Specific Site Specific Site Specific Magnitude Medium Medium Duration Medium-term Short-term Long-term Mitigation Measures As for C-4 None envisaged As for C-3 Consideration of Measures Typically a WBM has very low toxicity, with the vast majority of chemicals Y proposed for discharge considered PLONOR. However, contamination of sediments by heavier particles such as barite and bentonite is possible. Elevated levels of both elements have been noted in sediment analysis conducted at existing drill locations. Seabed surveys conducted in 2009 around the Cygnus exploration well, indicated that the barite discharged at the exploration well site in 2006 had not remained resident in the sediments but had dispersed over a wider area (UTEC Survey Ltd 2009b). The barium had become undetectable above background levels and reflected the natural variations in levels expected for the sediment type. In addition, the majority of the barite (79-90%) remained insoluble, unavailable to marine fauna, and in its insoluble form is considered non-toxic (Gerrand et al.1999 in UTEC Survey Ltd 2009b), see Section 8.4.2.4 for full details. The sediment analysis at the Cygnus exploration well therefore suggests that although some contamination will occur it will not change the classification of sediments from unpolluted to polluted. Cuttings discharged directly on the seabed from the wells will form deposition piles around the wellheads covering a maximum footprint of 631m 2 at each well. Given the five wells at each drill site will be located within close proximity to each other, the footprints are likely to overlap and the overall footprint could be higher. However, there will be approximately a one month gap between the drilling of each well and given evidence which shows cuttings piles in this area of the SNS disperse within 16 days, the area of seabed impacted at any one time is more likely to be equivalent to the seabed foot print for one well. Significant erosion of cuttings piles starts when the seabed current velocity exceeds 0.35ms -1 (UKOOA 1999) i.e., during storm events within the project area. Studies in the SNS have shown that drill cuttings mounds within this region of the SNS are quickly dispersed (see 8.4.4.2). Dispersed cuttings will be incorporated into the sediment through general sediment mobility. The wells will target a dry gas reservoir where the condensate-gas ratio is N - - - - 1.9bbl/mmscf (Section 6.4.2.1). Considering the mitigation measures, contamination of drilling fluids discharged to sea by condensate is not expected. RIA? (Y/N) Y Sensitivity Recoverability - - Importance - - Significance Report Section 8.4.5 8.4.5 8.4.5 CF00-00-EB-108-00001 Rev C1 Page 229 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect D-6 Installation of infrastructure D-7 Installation of infrastructure Physical presence and movement of transportation E - Plankton E-1 Drilling of wells. Installation of infrastucture Potential Impact Trenching Change / disturbance of surface sediments. Change in seabed topography Concrete mattressing and rock material (including rig stabilisation) Discharge of chemicals (including WBM) Change in seabed topography. Possible scour around object. Change / disturbance of seabed sediments Potential toxic effects Likelihood Definite Definite Definite Spatial extent Site Specific Site Specific Site Specific Magnitude Medium Medium Duration Medium-term Long-term Short-term Mitigation Measures Pipeline route will be optimised. Footprints on the seabed will be minimised through careful design. As for C-4 Consideration of Measures 1.32km 2 of seabed will be impacted by trenching. As the pipelines are Y trenched sediment will be repositioned on either side of the trench. If the trench is mechanically backfilled, these berms will then be pushed back into the trench by the backfill plough. If the trench will be naturally backfilled, the berms will be left and the trench will fill through sediment transportation. The bottom of the trenches will be approximately 3m and 2m below seabed level for the export and intra-field pipelines respectively. The route surveys showed that surface sediments in the project area, are generally up to 17m thick but from KP33 on the export pipeline route to the ETS pipeline tie-in the underlying Bolder Banks clay formation dominates at the surface. Trenching is likely to bring some of the underlying sediments to the surface locally changing surface sediments. Even in the event that the trench is backfilled mechanically, it is likely that small berms will be left on either side of the trench. Natural backfilling will only be undertaken following an assessment of BAT and BEP and as appropriate, modelling of sediments. Seabed profiles are expected to change slightly along the route, but not to any degree that will affect current movements, sediment transport or cause scour. A maximum of 36,600m 2 of seabed will be covered by concrete mattresses and rock placement. Evidence from the post drilling seabed clearance survey (Section 8.4.4.2) at the Cygnus exploration well (Rudall Blanchard Associates Ltd 2008) suggests material placed on the seabed in the high energy environment on top of the Dogger Bank (i.e., <20m water depth) will be covered by sand within three months. However, in the lower energy deeper waters towards the ETS pipeline tie-in, it is likely that the hard substrate will not be covered so quickly. The mattresses have a low profile (0.15m) and although the pipeline crossings will be higher (~2m) they cover a small area of seabed. It is unlikely that the deposition of material will change the topography significantly enough to affect sediment transport pathways or currents. N - - - - All discharges will be risk assessed and be within permitted levels. Although sensitive to changes in water quality, the plankton community undergoes a continual change in individuals with those from the surrounding waters and therefore has extremely rapid recovery rates. RIA? (Y/N) Sensitivity Recoverability - Importance - N - - - - Significance Report Section 8.4.5 8.4.5 9.1.5 CF00-00-EB-108-00001 Rev C1 Page 230 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section E-2 Drilling of wells Discharge of reservoir hydrocarbons Potential toxic effects Unlikely Site Specific Short-term As for C-3 The wells will target a dry gas reservoir where the condensate-gas ratio is N - - - - 1.9bbl/mmscf (Section 6.4.2.1). Considering the mitigation measures, contamination of drilling fluids discharged to sea by condensate is not expected. 9.1.5 E-3 Physical presence and movement of transportation F Benthic Ecology Discharge of sewage, grey water, food waste & drainage water Organic enrichment leading to raised biological oxygen demand. May increase plankton populations changing balance of food chain. Possible Site Specific Short-term As for C-1 It is likely that much of the sewage and grey water produced from construction vessels will be retained onboard. However, for the purposes of the assessment it has been assumed that all vessels could potentially discharge sewage and grey water, generating a maximum of 44,300m 3 of sewage and grey water during the entire construction period (Section 6.1.2.3). Although much of the project area is relatively shallow, it is considered that given the current speeds (average of 0.3ms -1 ), the refreshment rates in the area (<1hr) and the relatively small cumulative volumes of discharges, any discharge will be quickly dispersed and the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action (Section 8.3.5). It is likely that any degradation in water quality will be transient (limited to a few hours after the discharge) and there will be no residual impact water quality and therefore no residual impacts on plankton are expected. N - - - - 9.1.5 F-1 Installation of infrastructure Discharge of chemicals Drilling of wells (including WBM) Potential toxic effects. Definite Site specific Short-term As for C-4 Conditions in the vicinity of the development are such that any permitted discharges will be quickly dispersed (currents in the region [0.3ms -1 ] refresh a 500m radius column of water in <1hr). Discharged materials will therefore not be present within the water column for long enough or at concentrations that are likely to pose a significant toxic threat to marine ecology as a whole. Concentrations outside the immediate discharge area/time will be close to background or undetectable. N - - - - 9.2.5 CF00-00-EB-108-00001 Rev C1 Page 231 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section F-2 Physical presence and movement of Positioning structure on seabed e.g., transportation. jack-up legs, Installation of infrastructure platforms, other subsea structures, and anchors Physical damage to individuals. Habitat removal. Smothering. Definite Site Specific Medium Short-term Footprints on the seabed will be minimised through careful design and where possible, by positioning drilling rig legs in existing footprints on return to the sites. Opportunities to reduce the number of rig moves are currently being explored. Vessel operating procedures should ensure anchor drag is minimised. Positioning of vessels and structures on the seabed at the Cygnus Y development will disturb 1.46km 2 of seabed. This will result in the mortality of flora and fauna within the impact footprint. The species identified in the project area are typical of the SNS and Dogger Bank region and no rare or protected species were identified. The species present are generally tolerant of moderate disturbance and increased levels of suspended sediments as a consequence of the high energy environment and the strong storm events they are subject to. This suggests that individuals outside the direct impact footprint will be tolerant to increased levels of suspended sediments. The types of benthic communities that typically colonise such sediments have much faster recovery rates than those colonising low energy environments. The impact from the majority of the construction activities will cease within a few days or at most, a few months. A literature review on recovery rates (Metoc 2008b) concluded the recovery times in the area are likely to be in the region of three months to two years, i.e., short term. This is supported by the findings from survey data at the Cygnus exploration well site, where two years after operations ceased the site is nearly fully recovered. Although there will be a residual impact on the benthic ecology from physical disturbance to the seabed, which will be noticeable when compared to the baseline, disturbance will be localised, short-term and with no lasting effects. - - 9.2.5 F-3 Physical presence and movement of transportation Use of thrusters in shallow water Physical damage to individuals. Habitat removal. Smothering Possible Site Specific Short-term None envisaged The shallowest point along the pipeline route is 15.99m (Senergy 2011a). If a DP vessel is used, the maximum depth that thrusters will have an impact on the water column is approximately 14m from the sea surface. Below this depth the effects are generally not discernible from natural currents and wave orbital motions. However, the short distance to the seabed (2m) at the shallowest point may mean that seabed sediments are disturbed, increasing sediment loads. It is considered the disturbance will be similar to storm events. Benthic communities are typical of a moderately disturbed habitat where frequent storm events and tidal currents cause high levels of suspended sediments. The DP vessel will only be active along the pipeline routes for a maximum of 40 days and any disturbance will be transitory, therefore no residual impact on disturbance of surface sediments is anticipated. N - - - - 9.2.5 CF00-00-EB-108-00001 Rev C1 Page 232 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section F-4 Drilling of wells Discharge of cuttings. Smothering. Physical damage to individuals. Definite Site specific Medium Short-term None envisaged Cuttings discharged directly on the seabed from the ten wells will smother or kill sessile species within the impact footprint. Mobile species are expected to avoid areas of active disturbance. However, the benthic community in the project area is typical of the SNS and Dogger Bank habitat and no rare or protected species were identified in the environmental baseline surveys (Gardline Environmental 2011a, b). Studies in the SNS have shown that drill cuttings mounds are dispersed within a couple of weeks to a few months allowing rapid recolonisation of disturbed areas. As the benthic community is generally tolerant of moderate disturbance and increased levels of suspended sediments (see Section 9.2.5.2) recovery times are likely to be in the region of three months to two years (Metoc plc 2008b). Given all the above the residual impacts of drill cuttings on benthic communities is considered to be low. Y - - 9.2.5 F-5 Drilling of wells Discharge of reservoir hydrocarbons Potential toxic effects. Unlikely Site specific Short-term As for C-3 The wells will target a dry gas reservoir where the condensate-gas ratio is N - - - - 1.9bbl/mmscf (Section 6.4.2.1). Considering the mitigation measures, contamination of drilling fluids discharged to sea by condensate is not expected. 9.2.5 F-6 Installation of infrastructure Concrete mattressing and rock material Physical damage to individuals. Habitat removal. Smothering. Definite Site-specif Medium Medium-term Precise positioning of rock materials by manoeuvring the fall-pipe with an ROV, allowing accurate berm profiles to be built up. Only using sufficient material e.g., concrete mattresses or rock for protection or stabilisation. A maximum of 36,600m 2 of seabed will be covered by concrete mattresses and rock placement. Individuals will be smothered within the immediate footprint resulting in the localised mortality of flora and fauna. The post-drilling survey at the Cygnus exploration well suggested material placed in the high energy environment on top of the Bank is likely to be covered with sand within three months (Section 8.4.4.2) following which the area can be recolonised. However, in the lower energy deeper waters towards the ETS pipeline tie-in it is likely that the hard substrate will not be covered so quickly. These areas may be colonised by species that prefer harder substrates, but the rate of colonisation will be dependent on the level of larvae or juveniles in the surrounding area and communities will be different to the pre-impact structure. Y - - 9.2.5 CF00-00-EB-108-00001 Rev C1 Page 233 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section F-7 Installation of infrastructure Trenching Physical damage to individuals. Habitat removal. Smothering. Definite Site specific Medium Short-term Pipeline routes will be optimised. Trench profiles will be designed to minimise the creation of berms. A maximum of 1.32km 2 of seabed will be affected by trenching. During trenching, sediments will be placed as spoil piles on the seabed on either side of the trench. Sessile species within the sediments and in the footprint of the piles are likely to be killed. As discussed in D-6, trenching will also temporarily increase the levels of suspended sediment. Sand is likely to fall out of suspension within a few minutes, in close proximity to the pipeline route. Finer silt particles are likely to remain in suspension for longer before settling out over a much wider area. Sessile species within this deposition footprint will be smothered to some degree, and filter feeding mechanisms may become clogged. In addition, in the deeper waters along the export pipeline the underlying Bolders Bank formation clay may be bought to the surface during trenching locally changing the habitat. The benthic community is typical of the region being a moderately disturbed population with relatively few species and low abundance on the sandbank area. The key species identified in the project area are tolerant to increased suspended sediment loads (Section 9.2.5.2), and as such, recovery is expected within three months to two years (Metoc plc 2007). No rare or protected species were identified in the baseline survey (Gardline Environmental 2011a,b,c). N - - - - 9.2.5 G-Fish and Shellfish CF00-00-EB-108-00001 Rev C1 Page 234 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section G-1 Physical presence and movement of transportation. Installation of infrastructure. Drilling of wells. Subsea noise Species avoid spawning and nursery grounds. Physical damage to individuals. Possible Site specific Short-term None envisaged Levels of underwater noise generated by construction activities are generally below 180dB (see Section 6.1.2.4). Pile driving to secure the Cygnus platforms in place will be the main source of subsea noise and will generate sound source levels of 237dB re 1µPa at 1m (see Section 6.1.2.4). Piling will be limited to 36 hour periods for each platform. Little is known about the impact of subsea noise on fish. It is anticipated that species could show avoidance behaviour but that they will not have a sufficient dose to damage hearing. Investigations in relation to seismic survey s have shown a voluntary reaction and that at the moment the noise ceases, they return to their previous activities. In addition there is no perceived impact on long-term day to night shoal behaviour (Gausland 2003). The shorter duration of piling in comparison with a seismic survey indicates that there will not be a significant impact on adult fish from these activities. The development is an important area for spawning and nursery activity (see Section 9.3.2). Some species may avoid the area during the period of increased noise, but given the short-duration of the activity and the large spawning/nursery grounds, disturbance at the development site is not expected to significantly affect populations long-term. N - - - - 9.3.5 G-2 Physical presence and movement of transportation Discharge of sewage, grey water, food waste & drainage water Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Possible Local Short-term As for C-1 It is likely that much of the sewage and grey water produced from construction vessels will be retained onboard. However, for the purposes of the assessment it has been assumed that all vessels could potentially discharge sewage and grey water, generating a maximum of 44,300m 3 of sewage and grey water during the entire construction period (Section 6.1.2.3). Although much of the project area is relatively shallow, it is considered that given the current speeds (average of 0.3ms -1 ), the refreshment rates in the area (<1hr) and the relatively small cumulative volumes of discharges, any discharge will be quickly dispersed and the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action (Section 8.3.5). It is likely that any degradation in water quality will be transient (limited to a few hours after the discharge) and there will be no residual impact water quality and therefore no lasting effect on fish, shellfish or elasmobranchs is expected. N - - - - 9.3.5 CF00-00-EB-108-00001 Rev C1 Page 235 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect G-3 Physical presence and movement of transportation Installation of infrastructure Positioning structure on seabed e.g., jack-up legs, platforms, other subsea structures, and anchors G-4 Drilling of wells Discharge of cuttings G-5 Drilling of wells Installation of infrastructure Discharge of chemicals (including WBM) Potential Impact Loss of spawning and nursery ground affecting stock viability. Physical damage to individuals. Loss of spawning and nursery ground affecting stock viability. Potential toxic effects Likelihood Possible Definite Possible Spatial extent Site specific Site Specific Site specific Magnitude Medium Duration Short-term Short-term Short-term Mitigation Measures Footprints on the seabed will be minimised through careful design and where possible, by positioning drilling rig legs in existing footprints on return to the sites. Opportunities to reduce the number of rig moves are currently being explored. Vessel operating procedures should ensure anchor drag is minimised. None envisaged As for C-4 Consideration of Measures As construction activities at the Cygnus development will disturb 1.46km 2 of seabed, they have the potential to disturb the spawning grounds for demersal species. However, the area of potential impact is relatively small compared to the total spawning and nursery areas across the North Sea and given the disturbance will be short term, it is not considered that a small disruption at the development site will have an impact on stock viability or population levels (see section 9.3.5). There is a possibility that pelagic fish species could collide with the anchor chains and become entangled whilst the drilling rig is on station. There is no mitigation envisaged for this potential impact as it is a very minor risk. No residual impact is expected. RIA? (Y/N) Sensitivity Recoverability Importance N - - - - Cuttings discharged directly on the seabed from the ten wells will smother or kill sessile species within the impact footprint. Mobile species are expected to avoid areas of active disturbance and therefore the impact on individual species is expected to be negligible. Demersal species could be affected through temporary disturbance of habitat around drill centres. This would impact three out of the six species which spawn in the area. Whilst the development is located in and adjacent to six spawning and three nursery grounds, these make up only a small percentage of the total spawning and nursery areas across the North Sea. As such populations and stock viability should not be affected longterm and no residual impact is expected. N - - - - Conditions in the vicinity of the development are such that any permitted discharges will be quickly dispersed (currents in the region [0.3ms -1 ] refresh a 500m radius column of water in <1hr). Discharged materials will therefore not be present within the water column for long enough or at concentrations that are likely to pose a significant toxic threat to fish, shellfish and elasmobranchs. Concentrations outside the immediate discharge area/time will be close to background levels or undetectable. N - - - - Significance Report Section 9.3.5 9.3.5 9.3.5 G-6 Drilling of wells Discharge of reservoir hydrocarbons Potential toxic effects Possible Site specific Short-term As for C-3 The wells will target a dry gas reservoir where the condensate-gas ratio is N - - - - 1.9bbl/mmscf (Section 6.4.2.1). Considering the mitigation measures, contamination of drilling fluids discharged to sea by condensate is not expected. 9.3.5 CF00-00-EB-108-00001 Rev C1 Page 236 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section G-7 Installation of infrastructure Trenching Loss of spawning and nursery ground affecting stock viability. Possible Site specific Medium Short-term Pipeline route will be optimised. The seabed footprint of trenching the pipelines has been calculated as 1.46km 2. Although this is across the spawning grounds of six commercially important species and three nursery sites, D-6 concluded that trenching would have a low residual impact on surface sediments. This was due to the fact that in the deeper waters along the export pipeline route the underlying Bolders Bank formation clay may be brought to the surface during trenching locally changing the habitat. Those species which spawn demersally (three out of the six spawning species in the area) would be most affected, but as the spawning and nursery sites make up only a small percentage of the total area in the North Sea, the impact on fish populations in the area long-term is expected to be minimal. N - - - - 9.3.5 G-8 Installation of infrastructure Concrete mattressing and rock material Loss of spawning and nursery ground affecting stock viability. Possible Site specific Medium Short-term Precise positioning of rocks is possible by manoeuvring the fall-pipe with an ROV, allowing accurate berm profiles to be built up. Only sufficient material for protection or stabilisation will be used. A maximum of 36,600m 2 of seabed will be covered by concrete mattresses and rock placement. Although activities will result in a loss of some spawning and nursery grounds, the development site makes up only a small percentage of the total spawning and nursery areas for these species in the North Sea. Therefore the impact on fish populations is expected to be minimal and short-lived. N - - - - 9.3.5 H-Seabirds H-1 Physical presence and movement of transportation Drilling of wells. Installation of infrastructure Noise Avoidance of territorial areas Possible Site specific Short-term None envisaged In general, construction noise will be similar to general shipping activity, which is not known to significantly affect seabird distributions. However, pile and conductor driving will generate increased noise levels which may temporarily cause seabirds to avoid the construction area. Pile driving will be limited to approximately 36 hours per platform and each conductor will take only six hours to drive, therefore it is expected that seabirds will return to the area once the activity has stopped. N - - - - 9.4.5 CF00-00-EB-108-00001 Rev C1 Page 237 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect H-2 Physical presence and movement of transportation H-3 Drilling of wells. Installation of infrastructure Use of thrusters in shallow water Discharge of chemicals (including WBM) H-4 Drilling of wells Discharge of reservoir hydrocarbons Potential Impact Increased suspended sediment loads & turbidity effecting feeding Potential toxic effects Potential toxic effects. Likelihood Possible Possible Unlikely Spatial extent Site specific Side specific Magnitude Site specific Duration Short-term Short-term Short-term Mitigation Measures None envisaged As for C-4 As for C-3 Consideration of Measures The use of thrusters in the shallow water on top of the Bank has the potential to increase the suspended sediment load and affect turbidity which may have a knock-on effect on feeding seabirds. Diving seabirds may find it more difficult to feed in these conditions, but the overall water quality will not be affected long-term. The current speeds in the area (0.3ms -1 ) and the short-term scale of the activity will mean that the marine environment will recover quickly and long-term impacts on seabird species is expected to be minimal. RIA? (Y/N) Sensitivity Recoverability Importance N - - - - Conditions in the vicinity of the development are such that any permitted N - - - - discharges will be quickly dispersed (currents in the region [0.3ms -1 ] refresh a 500m radius column of water in <1hr). Discharged materials will therefore not be present within the water column for long enough or at concentrations that are likely to pose a significant toxic threat to seabirds. Concentrations outside the immediate discharge area/time will be close to background or undetectable. The wells will target a dry gas reservoir where the condensate-gas ratio is N - - - - 1.9bbl/mmscf (Section 6.4.2.1). Considering the mitigation measures, contamination of drilling fluids discharged to sea by condensate is not expected. Significance Report Section 9.4.5 9.4.5 9.4.5 CF00-00-EB-108-00001 Rev C1 Page 238 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section H-5 Installation of infrastructure Trenching Increased suspended sediment loads & turbidity effecting feeding Possible Spite specific Short-term None envisaged Installation of the pipeline will require trenching which will disturb seabed sediments. As a result, waters in the project area may experience increased suspended sediment loads and increased turbidity. Conditions could be magnified in the shallow water part of the pipeline route. These impacts could have a knock-on effect on feeding seabirds, especially those species that are divers. However, as discussed in C-6 the increased turbidity occurs against a back ground of seabed disturbance as a result of wave and tidal activity, is localised and very short-term (trenching is scheduled to take approximately forty days to complete). Therefore, any impacts on feeding birds are not expected to be significant and no residual impacts are expected. N - - - - 9.4.5 H-6 Physical presence and movement of transportation Discharge of sewage, grey water, food waste and drainage water Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Possible Site specific Short-term As for C-1 It is likely that much of the sewage and grey water produced from construction vessels will be retained onboard. However, for the purposes of the assessment it has been assumed that all vessels could potentially discharge sewage and grey water, generating a maximum of 44,300m 3 of sewage and grey water during the entire construction period (Section 6.1.2.3). Although much of the project area is relatively shallow, it is considered that given the current speeds (average of 0.3ms -1 ), the refreshment rates in the area (<1hr) and the relatively small cumulative volumes of discharges, any discharge will be quickly dispersed and the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action (Section 8.3.5). It is likely that any degradation in water quality will be transient (limited to a few hours after the discharge) and there will be no residual impact on water quality and therefore no lasting effect on seabirds is expected. N - - - - 9.4.5 CF00-00-EB-108-00001 Rev C1 Page 239 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section I-Marine Mammals I-1 Physical presence and movement of transportation. Installation of infrastructure Drilling of wells Subsea noise Can cause physical injury or disturbance Possible Local Medium Short-term The JNCC Statutory nature conservation agency protocol for minimising the risk of injury to marine mammals from piling noise (JNCC 2010) guidance will be followed. Levels of underwater noise generated by construction activities are Y generally below 180dB (see Section 6.1.2.4). Pile driving to secure the Cygnus platforms and subsea structures in place will be the main source of subsea noise. Driving the top section conductor will also generate noise but will create less due to the significantly smaller diameter. Piling is an impulsive sound, characterised by short percussive noise events resulting from the instantaneous application of pressure to a solid structure. For the full field development 18 platform piles and 8 smaller manifold and SSIV piles will be driven. 10 conductors will be driven. Piling will be limited in duration to approximately two hours per pile for the smaller piles and six hours per pile for the 1.5m platform piles. The conductor will take up to 6 hours. Piling of each structure will be undertaken during one 24 to 36 hour period. A noise assessment (see Section 9.5.5.1), to ascertain whether physical injury and/or disturbance thresholds are likely to be exceeded, found the sound experienced at 400m from the source does not exceed the injury thresholds and given the mitigation measures in place, there is negligible risk of an offence under the Habitats Regulations and Offshore Marine Conservation (Natural Habitats &c.) Regulations. Although calculations indicate that disturbance thresholds may be exceeded, JNCC guidance described disturbance as being a sustained or chronic disturbance and the duration of piling at Cygnus will be for less than two days at a time. Therefore it is considered that there is negligible risk of an offence and the residual impact on marine mammals has been assessed as low. - - 9.5.5 CF00-00-EB-108-00001 Rev C1 Page 240 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect I-2 Physical presence and movement of transportation I-3 Physical presence and movement of transportation I-4 Drilling of wells Installation of infrastructure Physical presence Discharge of sewage, grey water, food waste & drainage water Discharge of chemicals (including WBM) Potential Impact Increased risk of collision Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Potential toxic effects. Likelihood Possible Unlikely Possible Spatial extent Site-specific Local Site-specific Magnitude Duration Short-term Short-term Short-term Mitigation Measures During award of the contracts for any support vessels, DP vessels or self propelled barges, GDF SUEZ E&P UK will review the use of ducted propellers. Where possible vessels without these propellers will be preferentially selected, however if this is not feasible, GDF SUEZ E&P UK will consult with the JNCC concerning the use of MMOs. GDF SUEZ E&P UK will continue to consult with the JNCC in order to respond to any appropriate changes in best practice. As for C-1 As for C-4 Consideration of Measures During construction, a number of vessels will be used for a variety of construction activities (see Section 6.1.1.1). This increase in vessel activity has been identified as a potential concern for marine mammals which may be injured or killed as a result of a ship strike. Under the Habitats Directive it is an offence to disturb marine mammals. In and adjacent to the development area, five species of cetacean are present, and two species of pinniped. Three of these species are nonqualifying features of the Dogger Bank csac (see Section 9.6.2). However, the fact that the number of vessels is not expected to be considerably more than current levels in the area, it is considered that the residual impact will be of low significance as a change may only just be noticeable compared to the baseline. Recent reports have suggested that fatal injuries caused to pinnipeds may be the result of being drawn head-first through ducted propellers (Thompson et al. 2010). There is currently limited information about the extent of these instances or the significance of pinniped populations on the Dogger Bank, therefore the likelihood of this occurring during the project is unknown. It is considered that with the mitigation measures in place, the residual impact will be of low significance. It is likely that much of the sewage and grey water produced from construction vessels will be retained onboard. However, for the purposes of the assessment it has been assumed that all vessels could potentially discharge sewage and grey water, generating a maximum of 44,300m 3 of sewage and grey water during the entire construction period (Section 6.1.2.3). Although much of the project area is relatively shallow, it is considered that given the current speeds (average of 0.3ms -1 ), the refreshment rates in the area (<1hr) and the relatively small cumulative volumes of discharges, any discharge will be quickly dispersed and the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action. There is not expected to be any residual effect on water quality and therefore no lasting effect on marine mammals. Conditions in the vicinity of the development are such that any permitted discharges will be quickly dispersed (currents in the region [0.3ms -1 ] refresh a 500m radius column of water in <1hr). Discharged materials will therefore not be present within the water column for long enough or at concentrations that are likely to pose a significant toxic threat to marine mammals. Concentrations outside the immediate discharge area/time will be close to background or undetectable. RIA? (Y/N) Y Sensitivity Recoverability - Importance - N - - - - N - - - - Significance Report Section 9.5.5 9.5.5 9.5.5 CF00-00-EB-108-00001 Rev C1 Page 241 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section I-5 Drilling of wells Discharge of reservoir hydrocarbons Potential toxic effects. Smothering Unlikely Site-specific Short-term As for C-3 The wells will target a dry gas reservoir where the condensate-gas ratio is N - - - - 1.9bbl/mmscf (Section 6.4.2.1). Considering the mitigation measures, contamination of drilling fluids discharged to sea by condensate is not expected. 9.5.5 I-6 Physical presence and movement of transportation Use of thrusters in shallow water Could cause physical injury Possible Site-specific Short-term GDF SUEZ E&P UK will consult JNCC in advance of construction starting to determine whether any mitigation measures have been recommended that should be followed. Recent reports have been made with regard to fatal injuries to pinnipeds. Thompson et al. (2010) report 15 instances of harbour and grey seals found in Eastern Scotland and 24 in North Norfolk between 2008 and 2010 all showing spiral lacerations consistent with being drawn head first through a ducted propeller. In all cases the injuries were fatal. The report concludes that very limited information about the circumstances of the deaths is available and the potential extent of the issue is not yet known. It is likely that the incidents identified have occurred close to shore and have all been in areas with high seal populations (St Andrews Bay and Blakeney Point). It has possible a DP vessel will be used on the shallow bank where seals are known to occur, although not in high abundances. However, due to lack of available information it is not possible to determine the likelihood of this occurring during the project. N - - - - 9.5.5 J-Protected Sites and Species J-1 Physical presence and movement of transportation Use of thrusters in shallow water Could affect integrity of protected site Could harm protected species Possible Site specific Short-term None envisaged As discussed in D-2, it is considered the use of thrusters over the Dogger Bank at the shallowest point along the route will have a similar impact on the seabed as a normal storm event. As such the integrity of the bank is not likely to be affected. N - - - - 9.6.5 CF00-00-EB-108-00001 Rev C1 Page 242 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect J-2 Physical presence and movement of transportation Installation of infrastructure Drilling of wells J-3 Physical presence and movement of transportation Installation of infrastructure Potential Impact Subsea noise Can cause physical injury or disturbance to protected species Positioning structures on seabed e.g., jack-up legs, platforms, other subsea structures, and anchors Could affect integrity of protected site Likelihood Possible Definite Spatial extent Local Site specific Magnitude Medium Duration Short-term Long-term Mitigation Measures The JNCC Statutory nature conservation agency protocol for minimising the risk of injury to marine mammals from piling noise (JNCC 2010) guidance will be followed. Footprints on the seabed will be minimised through careful design and where possible, by positioning drilling rig legs in existing footprints on return to the sites. Opportunities to reduce the number of rig moves are currently being explored. Vessel operating procedures should ensure anchor drag is minimised. Consideration of Measures The development area is within the Dogger Bank csac. Its selection as a Y protected site is, in part, because it supports a population of harbour porpoise and grey and common seals are occasionally present. The three species are all non qualifying interest features under the EU Habitats Directive. As discussed in I-1 above a noise assessment to determine if marine mammals will be injured and or disturbed by construction activities (see Section 9.5.5.1 for full assessment) concluded that injury thresholds would not be exceeded and whilst disturbance thresholds could be exceeded, the duration would be less than two days at a time. JNCC guidance describes disturbance as being sustained or chronic disruption of behaviour. Therefore it is considered that there is negligible risk of an offence under the Habitats Regulations and Offshore Marine Conservation (Natural Habitats &c.) Regulations and the residual impact on marine mammals, has been assessed as low. No rare or protected species were identified in the baseline survey (Gardline Environmental 2011a, b). The development area is within the Dogger Bank csac which has been designated on account of its sandbank feature. JNCC assessed the Dogger Bank as being highly vulnerable to physical disturbance, such as oil and gas infrastructure development or pipeline burial. This assessment suggests that activities which cause physical disturbance may cause deterioration or disturbance to the sand bank which the designation protects (JNCC 2008a). Positioning of structures on the seabed at the Cygnus development will impact 1.46km 2 of seabed during construction. Of this, 1.22km 2 will be within the csac boundary. The csac encompasses 12,331km 2. Therefore, the footprint is equivalent to 0.01% of this site. As discussed in F-1 above, all impacts are likely to be restricted to the project area, the majority of construction activities will cease within a few days or at most, a few months and recovery rates are likely to be in the region of three months to two years i.e., short term. In addition, the high waveinduced sediment mobility is likely to infill scars left as a consequence of activities, and cover material placed on the seabed. Based on the above, the EIA concluded activities may cause short-term damage to the habitat which may be noticeable when compared to the baseline but that there will be no lasting effect on the integrity of the feature. As such it has been assessed as of low significance. RIA? (Y/N) Y Sensitivity Recoverability - - - - Importance Significance Report Section 9.6.5 9.6.5 CF00-00-EB-108-00001 Rev C1 Page 243 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section J-4 Physical presence and movement of transportation Discharge of sewage, grey water, food waste & drainage water Potential toxic effects on protected species. Unlikely Site specific Short-term As for C-1 As discussed above in C-1, although the project area is relatively shallow, it is considered that given the current speeds (average of 0.3ms -1 ), the refreshment rates in the area (<1hr), the short-time scale of the construction activity, and the relatively small cumulative volumes of discharges, any discharge will be quickly dispersed and the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action (Section 8.3.5). Considering the active mitigation in place it is likely that any degradation in water quality will be transient (limited to a few hours after the discharge) and there will be no residual impact water quality. As such it is unlikely that there will be any significant toxic effects on protected marine mammals in the project area and no residual impacts are expected. N - - - - 9.6.5 J-5 Drilling of wells Discharge of cuttings Could affect integrity of protected site Definite Site specific Short-term None envisaged No rare or protected species were identified in the baseline survey Y (Gardline Environmental 2011a, b). The development area is within the Dogger Bank csac which has been designated on account of its sandbank feature. JNCC have assessed the Dogger Bank as having low vulnerability to drill cuttings (JNCC 2008a). This is partly as evidence suggests that cuttings piles in the SNS are dispersed within a few months (see 8.4.5.2) and that the benthic community is of low abundance and diversity typical of a moderately disturbed habitat. - - 9.6.5 J-6 Drilling of wells Installation of infrastructure Discharge of chemicals (including WBM) Potential toxic effects on protected species. Definite Site specific Medium Medium-term As for C-4 No rare or protected species were identified in the baseline surveys (Gardline Environmental 2011a, b). The csac is important for seven species of marine mammal with three listed as non qualifying interest features of the protected site (harbour porpoise, common and grey seals) under the EU Habitats Directive. I-4 concluded that permitted chemical discharges would not have an impact on marine mammals. N - - - - 9.6.5 J-7 Drilling of wells Discharge of reservoir hydrocarbons Potential toxic effects on protected species. Unlikely Site specific Short-term As for C-3 The wells will target a dry gas reservoir where the condensate-gas ratio is N - - - - 1.9bbl/mmscf (Section 6.4.2.1). Considering the mitigation measures, contamination of drilling fluids discharged to sea by condensate is not expected. 9.6.5 CF00-00-EB-108-00001 Rev C1 Page 244 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section J-8 Installation of infrastructure Trenching Could affect integrity of protected site Definite Site specific Medium Short-term Pipeline route will be optimised. JNCC have assessed the biological and physical structure of the Dogger Y Bank has been impacted by the presence of oil and gas installations, however they note that on cessation of activities, the community naturally recovers (JNCC 2010b). Construction activities will disturb 1.46km 2 of seabed. Of this, 1.22km 2 is within the csac. This is equivalent to 0.01% of the area of the csac. Trenching will affect 1.32km 2 of seabed. The low faunal population and lack of surface vegetation indicate the benthic environment has no particular sensitivity for physical disturbance (Gardline Environmental 2011a,b). The sediments of the Dogger Bank are highly dynamic and the benthic communities there are tolerant to a moderate level of disturbance. It is considered that communities will recover within two months to three years. The high wave induced sediment mobility will infill the scars of the trenching and it is likely that although short term damage may be caused to the habitat, there will be no lasting effect on the integrity of the feature. - - 9.6.5 J-9 Installation of infrastructure. Concrete mattressing Drilling of wells and rock material Could affect integrity of protected site Definite Site specific Long-term Precise positioning of rocks is possible by manoeuvring the fall-pipe with an ROV, allowing accurate berm profiles to be built up. Only sufficient material for protection or stabilisation will be used. JNCC have assessed the biological and physical structure of the Dogger Bank has been impacted by the presence of oil and gas installations, however they note that on cessation of activities, the community naturally recovers (JNCC 2010b). A maximum of 36,600m 2 of seabed will be covered by concrete mattresses and rock placement. This will change approximately 0.0003% of the csac area from a sandy habitat to one dominated by hard substrate. This is an extremely small proportion of the protected area and is not expected to affect the integrity of the feature. Using only the necessary amount of material will help mitigate against unnecessary habitat loss. Evidence suggests that hard material on the top of the Bank may become covered by sand due to the high energy environment and sediment transport. It is considered that, although there will be some habitat loss causing a short term impact, the areas will be recolonised as sediment coverage increases and the residual impact will be low. Y - - 9.6.5 CF00-00-EB-108-00001 Rev C1 Page 245 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section K-Commercial Fishing K-1 Physical presence and movement of transportation Exclusion zones Exclusion from fishing grounds. Increased collision risk. Definite Site Specific Short-term A 500m safety exclusion zone around the drilling rig(s), platforms and subsea infrastructure will be enforced. To reduce the likelihood of collision, the drilling rig, platforms and construction vessels will be appropriately lit and sound warnings will be broadcast in poor visibility. Users of the sea will be notified of the presence and intended movements of construction vessels, presence of exclusion zones and the presence of new structures and areas of mattressing or rock material via the Kingfisher Fortnightly Bulletins, Notices to Mariners and VHF radio broadcasts. All vessels will follow the IMO Standards and will be properly marked. The pipelay vessel will have a National Federation of Fishermen's Organisations (NFFO) approved Fisheries Liaison Officer (FLO) onboard who will regularly communicate coordinates to the fishing industry. It is standard practice to establish a 500m safety exclusion zone around the drilling rig to prevent collisions. Fishing vessels will be excluded from this area for the duration of construction activities. Drilling will be undertaken between May 2013 and September 2016. A 500m exclusion zone will also be in place along the pipeline route. In total, an area of 27km 2 would be excluded but in reality the exclusion zone will be much smaller and will migrate along the pipeline route as sections are being laid. If vessels were excluded from the entire area this would represent <0.1% of an ICES rectangle. The project area has a moderate relative value for commercial species with a relatively high catch per unit effort (see Section 9.1.2). However, fishing vessels will be able to relocate and it is not considered that the impact will be significant. Y - - 10.1.5 K-2 Physical presence and movement of transportation Anchoring Persistent anchor piles could snag fishing gear Unlikely Site specific Short-term None envisaged The heavy lift vessel and anchor lay barge could create anchor mounds. Given the nature of the sediments (loose coarse to fine sands) in the project area and the high energy environment it is expected that these mounds will disperse rapidly. As such the risk of fishing gear snagging on the mounds is temporary and will not have a residual impact. N - - - - 10.1.5 CF00-00-EB-108-00001 Rev C1 Page 246 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section K-3 Drilling of wells Discharge of cuttings Persistent drill cuttings piles could snag gear. Unlikely Site Specific Short-term None envisaged Although drilling will generate cuttings piles these will be directly underneath the Cygnus A and B platforms. As fishing vessels will be excluded from an area of 500m radius around the drilling rig the risk of gear snagging is extremely low. N - - - - 10.1.5 K-4 Installation of infrastructure Trenching Persistent spoil piles could snag fishing gear Unlikely Site Specific Short-term Trench profiles will be designed to minimise the creation of berms. During trenching of the pipeline, material is removed and deposited either side along the pipeline route in berms approximately 3m wide and 2m high. If the trench is mechanically backfilled, these berms will then be pushed back into the trench by the backfill plough. If the trench is naturally backfilled, the berms will be left and the trench will fill through sediment transportation. Even in the event that the trench is backfilled mechanically, it is likely that small berms will be left on either side of the trench. Should spoil piles be left, these will be very shallow, comprising fine sand and will be quickly dispersed due to the high energy environment on the bank. It is not thought they will present a snagging hazard to the fishing industry. Natural backfilling will only be undertaken following an assessment of BAT and BEP and as appropriate, modelling of sediments. This will consider the potential impact of the berms on fishing. N - - - - 10.1.5 K-5 Installation of infrastructure Concrete mattressing and rock material Could snag fishing gear Possible Site Specific Short-term Fishermen will be informed of seabed deposits via the Kingfisher Fortnightly Bulletins and Notices to Mariners. Precise positioning of rock material by manoeuvring the fall-pipe with an ROV, allowing accurate berm profiles to be built up. Profiles of the pipeline crossings will be designed to minimise snagging potential. Only using sufficient material e.g., concrete mattresses or rock for protection or stabilisation. A maximum of 36,600m 2 of seabed will be covered by concrete mattresses and rock placement. It is possible that fishing gear could become snagged on rock material or mattresses which have a raised profile in comparison to the seabed. Protecting pipeline crossings is a standard practice and the mitigation measures in place have proven to be sufficient to negate the impact on fishing gear from snagging. With regards to the impact on fish populations for commercial fishing, it is possible that pipelines could play an ecologically significant role as a nursery ground for juveniles of commercially important fish species and habitat for benthic invertebrates (Metoc plc 2008b). In the long-term this could bring benefits to the commercial fishing industry in the area. N - - - - 10.1.5 CF00-00-EB-108-00001 Rev C1 Page 247 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section K-6 Installation of infrastructure Positioning structures on seabed e.g., SSIV wye manifold Could snag fishing gear Possible Site-specific Long-term A 500m safety zone will be The mitigation measures are sufficient to preclude any impacts on established around subsea commercial fishing and no residual impacts are anticipated. infrastructure Users of the sea will be informed of the structures presence via the Kingfisher Fortnightly Bulletins and Notices to Mariners. Subsea structures will be designed to be fishing friendly with no snag points. GDF SUEZ E&P UK will consider using a guard vessel to protect the pipelines for the period between being laid on the seabed and being trenched. The vessel will liaise with fishing vessels in the area to ensure that they are aware of the pipeline and risks involved with trawling over it. If the pipeline is mechanically buried, this should reduce the likelihood of snagging of fishing gear. The assessment of natural backfill will consider the potential for snagging of fishing gear when determining whether it is an appropriate course of action. The pipelay vessel will have an NFFO approved Fisheries Liaison Officer (FLO) onboard who will regularly communicate coordinates to the fishing industry. N - - - - 10.1.5 CF00-00-EB-108-00001 Rev C1 Page 248 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect L-Shipping and Navigation L-1 Physical presence and movement of transportation Physical presence / exclusion zones Potential Impact Obstruction of shipping lanes leading to increased collision risk. Likelihood Unlikely Spatial extent Site specific Magnitude Duration Short-term Mitigation Measures Consideration of Measures A 500m safety exclusion zone will be 500m safety exclusion zones will be established around the platforms Y enforced around the drilling rig, and drilling rig, along the pipeline route and the subsea infrastructure platforms, subsea infrastructure. To during construction. The collision risk assessment undertaken for the reduce the likelihood of collision, the field (Anatec 2011) concluded that there is sufficient sea room available drilling rig, platforms and construction for vessels using the routes to manoeuvre however, even considering the vessels will be appropriately lit and mitigation measures in place, it is possible that vessels will have to reroute as a result of the exclusion zones. It is considered that this will sound warnings will be broadcast in poor visibility have a low impact on shipping. Users of the sea will be informed of the structures presence via the Kingfisher Fortnightly Bulletins and Notices to Mariners. GDF SUEZ E&P UK will have a collision risk management plan in place for the proposed development, compliant with IMO standard requirements. All vessels will follow IMO standards and will be properly marked. The pipelay vessel will have an NFFO approved Fisheries Liaison Officer (FLO) onboard who will regularly communicate coordinates to the fishing industry. RIA? (Y/N) Sensitivity Recoverability - - Importance Significance Report Section 10.2.5 M-Other Marine Users M-1 Physical presence and movement of transportation Physical presence / exclusion zones Increased vessel activity and obstructions leading to increased collision risk. Unlikely Site specific Short-term As for L-1 The mitigation measures are sufficient to preclude any impacts on other marine users and no residual impacts are anticipated. N - - - - 10.3.5 CF00-00-EB-108-00001 Rev C1 Page 249 of 300

N-Archaeology N-1 Physical presence and movement of transportation. Installation of infrastructure N-2 Physical presence and movement of transportation N-3 Installation of infrastructure Positioning structures on seabed e.g., jack-up legs, platforms, anchors, subsea structures Use of thrusters in shallow water Trenching Could disturb or damage currently unknown maritime archaeological features. Could disturb or damage currently unknown maritime archaeological features. Removal of protective overburden can leave remains with insufficient cover to protect them from activities such as trawling. Possible Possible Possible Site specific Site specific Site specific Short-term Short-term Short-term The British Marine Aggregate Producers Association (BMAPA) protocol will be followed should any It has been estimated that 1.46km 2 of seabed will be affected by the construction activities. No archaeological features other than a wreck, were identified during the site surveys (Gardline Environmental N - - - - artefacts be discovered on the seabed 2011a,b,c). The mitigation measures in place will ensure that damage to which could potentially be of archaeological significance. any previously undiscovered archaeological feature is likely to be minimised and will be properly reported. Activities undertaken during construction are not considered likely to have a residual impact. N - - - - N - - - - 10.4.5 10.4.5 10.4.5 CF00-00-EB-108-00001 Rev C1 Page 250 of 300

2.3 PRODUCTION Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect A Air Quality Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section A-1 Physical presence and movement of transportation Exhaust gas emissions Localised deterioration in air quality. Unlikely Site specific Long-term Ensure all machinery is maintained and serviced. Use of low sulphur content fuels where possible. It has been estimated that approximately 90 tonnes of NO x and 3.1 tonnes of SO x will be emitted by support vessels per annum from the field development. Dispersion modelling, undertaken for activities burning 15 tonnes of fuel per day, associated with the Cygnus exploration well demonstrated that concentrations of NO x and SO x were diluted to <1μgm -3 within 500m of the discharge point, well below health and environmental guidelines. All daily use figures are comparable to the figures modelled and it can be assumed that concentrations of NO x and SO x will be diluted to similar concentrations in the generally windy offshore environment. N - - - - 8.1.5 A-2 Power generation Exhaust gas emissions Localised deterioration in air quality. Unlikely Site specific Long-term Inspection and maintenance programmes will be used in line with the requirements of indicative BAT to ensure that combustion equipment is kept and operated in a manner to optimise efficiency and minimise fuel consumption where appropriate Use of low sulphur content fuels where possible. Emissions from power generation will be managed under the appropriate permits for the development. Energy efficiency will be investigated as part of permitting (e.g., PPC permit, GHG permit, EU ETS). It is estimated that power generation will result in the emission of 2,542 tonnes of CO 2, 8 tonnes of NO x and 3.15 tonnes of SO x per annum. Emissions are generally comparable with other manned installations in the SNS. Given the generally dynamic environment offshore, concentrations of NO x and SO x and expected to reach European Commission alert thresholds and no residual impacts on regional air quality are expected. N - - - - 8.1.5 A-3 Gas venting Release of gas Localised deterioration in air quality. Unlikely Site specific Long-term Venting will be within permitted levels as outlined in the relevant permits and will be kept to the minimum required for safe operations Natural gas may be vented for operational or safety purposes. Any venting will be undertaken within the conditions of the applicable consent. On release to air, natural gas will have a minor risk of causing toxic or asphyxiant affects. Cygnus gas contains approximately 87% methane meaning that it will rapidly disperse and dilute in the air. Any degradation in air quality will be transient and no residual impacts are expected. N - - - - 8.1.5 CF00-00-EB-108-00001 Rev C1 Page 251 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect A-4 Flaring Release of combustion gases B Climate Change B-1 Physical presence and movement of transportation B-2 Power generation Exhaust gas emissions Exhaust gas emissions B-3 Gas venting Release of gas Potential Impact Localised deterioration in air quality. Loading of greenhouse gases e.g., CO2, CH4 Loading of greenhouse gases e.g., CO 2, CH 4 Loading of greenhouse gases e.g., CO 2, CH 4 Likelihood Unlikely Spatial extent Site Specific Magnitude Unlikely Site specific Unlikely Unlikely Site specific Site specific Duration Long- term Long-term Long-term Long-term Mitigation Measures Flaring will be within permitted levels as outlined in the relevant permits and will be kept to the minimum required for safe operations High efficiency burners will be used for flaring. Ensure all machinery is maintained and serviced. Use of low sulphur content fuels where possible. Select combustion equipment in line with the requirements of indicative BAT, to minimise emissions and energy consumption. Inspection and maintenance programmes will be used in line with the requirements of indicative BAT to ensure that combustion equipment is kept and operated in a manner to optimise efficiency and minimise fuel consumption where appropriate. Emissions from power generation equipment will be managed under the appropriate permit conditions. Energy efficiency will be investigated as part of permitting (e.g., PPC permit, GHG permit, EU ETS). Venting will be within permitted levels and kept to the minimum required for safe operations Consideration of Measures Any deterioration in air quality around the Cygnus A platform is expected to be extremely localised; the prevailing atmospheric conditions indicate that combustion emissions will quickly be dispersed and it is not expected that flaring will noticeably impact regional air quality. RIA? (Y/N) Sensitivity Recoverability Importance N - - - - It has been estimated that approximately 4,933 tonnes of CO 2 will be emitted by support vessels per annum from the field development. This represents 0.1% of the annual offshore emissions for similar activities in 2009 (OGUK 2009). This is a negligible contributor to annual UK emissions. N - - - - Approximately 2,542 tonnes of CO 2 will be emitted from power generation. This represents 0.005% of the annual offshore emissions for similar activities in 2009 (OGUK 2009). This is a relatively small contributor to annual UK emissions, and is in line with similar developments of this size. It is not considered that this development will cause a significant contribution to climate change. N - - - - Natural gas may be vented for operational or safety purposes. Any venting will be undertaken within the conditions of the vent consent. Cygnus gas contains approximately 87% methane meaning that it will rapidly disperse and dilute in the air. Quantities vented are expected to be minimal and negligible in relation to standard UK greenhouse gas emitters such as transport and power stations N - - - - Significance Report Section 8.1.5 8.2.5 8.2.5 8.2.5 CF00-00-EB-108-00001 Rev C1 Page 252 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section B-4 Flaring Release of combustion gases Loading of greenhouse gases e.g., CO 2, CH 4 Unlikely Site specific Long-term Flaring will be within permitted levels and kept to the minimum required for safe operations High efficiency burners will be used for flaring. Flaring will be undertaken to safely dispose of natural gas when required for operational or safety purposes. It will be undertaken within the requirements of the relevant permits and consents. Quantities of gas flared are expected to be minimal and it is not considered that they will have a significant impact on climate change N - - - - 8.2.5 C Water Resources C-1 Presence of platform Physical presence and movement of transportation Discharge of sewage, grey water, food waste and drainage water Deterioration in water quality Unlikely Site specific Long-term GDF SUEZ E&P UK are currently considering sewage treatment options for Cygnus A. Where possible they will endeavour to follow industry best practice for the region. Waste storage procedures will be compliant with the International Convention for the Prevention of Pollution from Ships (1973/1978) (Marpol 73/78) and its Annexes. Paper and food wastes will be disposed of in a manner that is compliant with the relevant regulations. No plastics nor plastic containing material, will be disposed at sea, regardless of location. Solid wastes will be compacted where possible and stored for appropriate disposal ashore. All project associated vessels will work to IMO standards. The positioning of bunds / drip trays will be considered during detailed design. Non-hazardous and hazardous area drains will be diverted to the oil / water separator, where oil will be removed. Given the prevalent metocean conditions in the project area (e.g., winds, N - - - - waves, tides and currents) and the small cumulative volume of discharges, the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action. Any degradation in water quality will be transient (limited to a few hours after the discharge) and there will not be any residual impacts on water quality. 8.3.5 CF00-00-EB-108-00001 Rev C1 Page 253 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section C-2 Produced water Discharge of reservoir hydrocarbo ns Deterioration in water quality Unlikely Site specific Long-term All oil discharges will be covered by an approved OPPC permit. Produced water discharge will be closely monitored to ensure that all contaminants are at an acceptable level. Oil in water, chemical, aromatic and radionuclide concentrations will all be reported via the appropriate permit i.e., PON15D or OPPC. It is anticipated that a maximum of 9.5kg of condensate could be discharged in the produced water per annum with normal operations likely to result in 0.95 kg discharged per day. Given the quantities involved and the high energy dispersive environment at the discharge point, it is not considered that there is a significant risk of residual impacts on water quality. N - - - - 8.3.5 C-3 Maintenance of platforms, pipelines and wells Discharge of chemicals Deterioration in water quality Unlikely Local Long-term Selections of chemicals will be made in accordance with the CEFAS ranked list, where chemicals ranked as lower potential hazards are preferentially chosen. Only chemicals permitted through the PON15 D and that have been subject to a risk assessment will be discharged. All production chemicals will be in closed systems with no discharge to sea. N - - - - 8.3.5 D Seabed Conditions D-1 Produced water Discharge of reservoir hydrocarbo ns Sediment contamination Unlikely Site specific Long-term As for C-2 It is anticipated that a maximum of 9.5kg of condensate could be discharged in the produced water per annum with normal operations likely to result in 0.95 kg discharged per day. Given the quantities involved and the high energy dispersive environment at the discharge point, it is not considered that there is a significant risk of sediment contamination. N - - - - 8.4.5 D-2 Maintenance of platform, pipelines and wells Discharge of chemicals Sediment contamination Unlikely Site specific Long-term As for C-3 All production chemicals will be in closed systems with no discharge to sea. N - - - - 8.4.5 CF00-00-EB-108-00001 Rev C1 Page 254 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect E - Plankton Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section E-1 Presence of platforms Physical presence and movement of transportation Discharge of sewage, grey water, food waste and drainage water Organic enrichment leading to raised biological oxygen demand. May increase plankton populations changing balance of food chain. Unlikely Site specific Long-term As for C-1 Given the prevalent metocean conditions in the project area (e.g., winds, N - - - - waves, tides and currents) and the small cumulative volume of discharges, the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action. Any degradation in water quality will be transient (limited to a few hours after the discharge) and there will not be any residual impacts on water quality. It is therefore considered that there is unlikely to be any significant change in plankton populations. 9.1.5 E-2 Produced water Discharge of reservoir hydrocarbo ns Potential toxic effects Unlikely Site specific Long-term As for C-2 It is anticipated that a maximum of 9.5kg of condensate could be discharged in the produced water per annum with normal operations likely to result in 0.95 kg discharged per day. Given the quantities involved and the high energy dispersive environment at the discharge point, it is not considered that there is a significant risk of toxic effects on the plankton community. N - - - - 9.1.5 E-3 Maintenance of platforms, pipelines and wells Discharge of chemicals Potential toxic effects Unlikely Local Long-term As for C-3 All production chemicals will be in closed systems with no discharge to sea. N - - - - 9.1.5 F Benthic Ecology F-1 Produced water Discharge of reservoir hydrocarbo ns Potential toxic effects Unlikely Site specific Long-term As for C-2 It is anticipated that a maximum of 9.5kg of condensate could be discharged in the produced water per annum with normal operations likely to result in 0.95 kg discharged per day. Given the quantities involved and the high energy dispersive environment at the discharge point, it is not considered that there is a significant risk of toxic effects on benthic ecology. N - - - - 9.2.5 CF00-00-EB-108-00001 Rev C1 Page 255 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section F-2 Maintenance of platforms, pipelines and wells Discharge of chemicals Potential toxic effects Unlikely Local Long-term As for C-3 All production chemicals will be in closed systems with no discharge to sea. N - - - - 9.2.5 F-3 Presence of platforms Physical presence and movement of transportation Discharge of sewage, grey water, food waste and drainage water Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Unlikely Site specific Long-term As for C-1 Given the prevalent metocean conditions in the project area (e.g. winds, waves, tides and currents) and the small cumulative volume of discharges, the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action. Any degradation in water quality will be transient (limited to a few hours after the discharge) and there will not be any residual impacts on water quality. It is therefore considered that there is unlikely to be any significant change in the benthic community. N - - - - 9.2.5 G-Fish and Shellfish G-1 Produced water Discharge of reservoir hydrocarbo ns Smothering Potential toxic effects Unlikely Site specific Long-term As for C-2 It is anticipated that a maximum of 9.5kg of condensate could be discharged in the produced water per annum with normal operations likely to result in 0.95 kg discharged per day. Given the quantities involved and the high energy dispersive environment at the discharge point, it is not considered that there is a significant risk of smothering or toxic effects on fish and shellfish. N - - - - 9.3.5 G-2 Presence of platforms Discharge of sewage, grey water, food waste & drainage water Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Unlikely Site specific Long-term As for C-1 Given the prevalent metocean conditions in the project area (e.g. winds, waves, tides and currents) and the small cumulative volume of discharges, the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action. Any degradation in water quality will be transient (limited to a few hours after the discharge) and there will not be any residual impacts on water quality. It is therefore considered that there is unlikely to be any significant change in the food chain. N - - - - 9.3.5 CF00-00-EB-108-00001 Rev C1 Page 256 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section G-3 Maintenance of platform, pipelines and wells Discharges of chemicals Potential acute or long-term toxic effects which may affect balance of food chain. Unlikely Local Long-term As for C-3 All production chemicals will be in closed systems with no discharge to sea. N - - - - 9.3.5 H - Seabirds H-1 Presence of platforms Physical presence and movement of transportation H-2 Presence of platforms Physical presence and movement of transportation Discharge of sewage, grey water, food waste and drainage water Emission of light Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Disturbance of migratory routes and changes to behaviour Unlikely Site specific Long-term As for C-1 Given the prevalent metocean conditions in the project area (e.g. winds, waves, tides and currents) and the small cumulative volume of discharges, the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action. Any degradation in water quality will be transient (limited to a few hours after the discharge) and there will not be any residual impacts on water quality. It is therefore considered that there is unlikely to be any significant change in the food chain. N - - - - - - - - - There is not sufficient information publically available to inform an assessment of the potential impact of artificial light from the platforms on the migration of birds during darkness, therefore an EIA has not been undertaken. - - - - - 9.4.5 9.4.5 H-3 Physical presence and movement of transportation H-4 Maintenance of platforms, pipelines and wells Noise Discharge of chemicals Avoidance of territorial areas Potential toxic effects through bioaccumulation of chemicals in food chain. Unlikely Unlikely Site specific Local Long-term Long-term None envisaged. As for C-3 During production a range of activities will generate subsea noise including vessel manoeuvring and power generation, however these activities generally create noise levels that are below 180dB. It is not considered that production noise levels will adversely affect seabird populations and there is no evidence to suggest that birds avoid the area around production platforms. All production chemicals will be in closed systems with no discharge to sea. N - - - - N - - - - 9.4.5 9.4.5 CF00-00-EB-108-00001 Rev C1 Page 257 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section H-5 Produced water Discharge of reservoir hydrocarbo ns Smothering Potential toxic effects Unlikely Site specific Long-term As for C-2 It is anticipated that a maximum of 9.5kg of condensate could be discharged in the produced water per day with normal operations likely to result in 0.95kg discharged per day. Given the quantities involved and the high energy dispersive environment at the discharge point, it is not considered that there is a significant risk of smothering or toxic effects on seabirds. N - - - - 9.4.5 I Marine Mammals I-1 Presence of platforms I-2 Physical presence and movement of transportation I-3 Physical presence and movement of transportation Presence of platforms Discharge of sewage, grey water, food waste and drainage water Physical presence Subsea noise Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Increased risk of collision Can cause physical injury or disturbance Unlikely Unlikely Definite Site specific Site specific Site specific Long-term Long-term Long-term As for C-1 None envisaged None envisaged Given the prevalent metocean conditions in the project area (e.g. winds, waves, tides and currents) and the small cumulative volume of discharges, the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action. Any degradation in water quality will be transient (limited to a few hours after the discharge) and there will not be any residual impacts on water quality. It is therefore considered that there is unlikely to be any significant change in the food chain. N - - - - Cygnus A will require the presence of a standby vessel at all times. In addition there will be approximately one visit by a supply vessel per week (estimated maximum 64 per year). This increase in vessel movements is unlikely to be noticed above the current background of shipping and other vessel movements in this area (Section 10.2.2). It is therefore considered that vessel movements associated with the platforms are unlikely to significantly increase the potential for a collision with marine mammals and will not result in a residual impact. During production a range of activities will generate subsea noise including vessel manoeuvring and power generation. Noise levels are expected to be below disturbance thresholds outside the immediate area of the power generators and will not be at a level that would cause physical injury or disturbance. Todd et al. (2009) concluded that offshore fixed installations could be an important foraging area for harbour porpoises, with individuals recorded frequenting the structures with surprising regularity at night. N - - - - N - - - - 9.5.5 9.5.5 9.5.5 CF00-00-EB-108-00001 Rev C1 Page 258 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section I-4 Produced water Discharge of reservoir hydrocarbo ns Smothering Unlikely Site specific Long-term As for C-2 It is anticipated that a maximum of 9.5kg of condensate could be discharged in the produced water per day with normal operations likely to result in 0.95kg discharged per day. Given the quantities involved and the high energy dispersive environment at the discharge point, it is not considered that there is a significant risk of smothering to marine mammals. N - - - - 9.5.5 I-5 Maintenance of platforms, pipelines and wells Discharge of chemicals Potential toxic effects through bioaccumulation of chemicals in food chain. Unlikely Local Long-term As for C-3 All production chemicals will be in closed systems with no discharge to sea. N - - - - 9.5.5 J Protected Sites and Species J-1 Produced water Discharge of reservoir hydrocarbo ns Potential toxic effects through bioaccumulation of chemicals in food chain. Unlikely Site specific Long-term As for C-2 It is anticipated that a maximum of 9.5kg of condensate could be discharged in the produced water per annum with normal operations likely to result in 0.95 kg discharged per day. Given the quantities involved and the high energy dispersive environment at the discharge point, it is not considered that there is a significant risk of smothering to marine mammals. N - - - - 9.6.5 J-2 Maintenance of platforms, pipelines and wells Discharge of chemicals Potential toxic effects through bioaccumulation of chemicals in food chain. Unlikely Site specific Long-term As for C-3 All production chemicals will be in closed systems with no discharge to sea. N - - - - 9.6.5 J-3 Physical presence and movement of transportation Discharge of sewage, grey water, food waste and drainage water Organic enrichment leading to raised biological oxygen demand. May increase plankton & fish populations changing balance of food chain. Unlikely Site specific Long-term As for C-1 Given the prevalent metocean conditions in the project area (e.g. winds, waves, tides and currents) and the small cumulative volume of discharges, the marine environment will be able to rapidly assimilate the discharges and deal with them through natural bacterial action. Any degradation in water quality will be transient (limited to a few hours after the discharge) and there will not be any residual impacts on water quality. It is therefore considered that there is unlikely to be any significant change in the food chain. N - - - - 9.6.5 CF00-00-EB-108-00001 Rev C1 Page 259 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section J-4 Physical presence and movement of transportation Physical presence Increased collision risk Possible Site specific Medium Long-term None envisaged I-2 concluded that the increase in vessel movements would not have a residual impact on marine mammals which are EPS. N - - - - 9.6.5 J-5 Physical presence and movement of transportation Presence of platforms Subsea noise Can cause physical injury or disturbance to protected species Definite Site specific Long-term None envisaged I-3 concluded that subsea noise would not have a residual impact on marine mammals which are EPS. N - - - - 9.6.5 K Commercial Fishing K-1 Presence of platforms Exclusion zones Exclusion from fishing grounds. Increased collision risk. Definite Site specific Long-term A 500m safety exclusion zone will be It is standard practice to establish a 500m safety exclusion zone around Y enforced around the platforms. platforms to prevent collisions. Fishing vessels will be excluded from The platforms will be appropriately this 2.35km 2 for the life of the platforms and as such the residual impact marked and lit and sound warnings will be has been assessed as low. broadcast in poor visibility. The project area has a moderate relative value for commercial species Users of the sea will be informed of the with a relatively high catch per unit effort (see Section 9.1.2). However, structures presence via the Kingfisher fishing vessels will be able to relocate. Fortnightly Bulletins, Notices to Mariners and where appropriate VHF radio broadcasts. GDF SUEZ E&P UK will have a collision risk management plan in place for the proposed development, compliant with IMO standard requirements. - - 10.1.5 CF00-00-EB-108-00001 Rev C1 Page 260 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section K-2 Physical presence and movement of transportation Physical presence Increased vessel activity leading to increased collision risk Possible Site specific Long-term All vessels will follow the IMO standards and will be properly marked Cygnus A will require the presence of a standby vessel at all times. In addition there will be approximately one visit by a supply vessel per week (estimated maximum 64 per year). This increase in vessel movements is unlikely to be noticed above the current background of shipping and other vessel movements in this area (Section 10.2.2). It is therefore considered that vessel movements associated with the platforms are unlikely to significantly increase the potential for a collision with a fishing vessel. N - - - - 10.1.5 L Shipping and Navigation L-1 Presence of platform L-2 Physical presence and movement of transportation Physical presence / exclusion zones Physical presence M Other Marine Users Obstruction of shipping lanes leading to increased collision risk Increased vessel activity leading to increased collision risk. Possible Site specific Medium Possible Site specific Medium Long-term Long-term As for K-1 All vessels will follow the IMO standards and will be properly marked 500m safety exclusion zones will be established around the platforms. Y Shipping studies undertaken for the development (Anatec 2011) indicate that the risk of collision with the Cygnus A platform is1x10-4 with a collision return period of 9,900 years and the risk of collision with the Cygnus B platform is 4x10-4 with a return period of 2,500 years. Although the collision risk for Cygnus A is below the historical average for UKCS offshore installations, the collision risk for Cygnus B is greater than the historical average. However, the collision risk assessment concluded that there is sufficient sea room available for vessels using the routes to manoeuvre around a fixed obstruction. Given the high density of shipping in the SNS even considering the mitigation measures, it is still possible that the presence of the exclusion zones may lead to vessels re-routing. The residual impact of the presence of the platforms on shipping and navigation has been assessed as of low significance. Cygnus A will require the presence of a standby vessel at all times. In addition there will be approximately one visit by a supply vessel per week (estimated maximum 64 per year). This increase in vessel movements is unlikely to be noticed above the current background of shipping and other vessel movements in this area (Section 10.2.2). - - N - - - - 10.2.5 10.2.5 CF00-00-EB-108-00001 Rev C1 Page 261 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect M-1 Presence of platforms M-2 Physical presence and movement of transportation Physical presence / exclusion zones Physical presence / exclusion zones Potential Impact Potential collision risk Potential collision risk Likelihood Spatial extent Magnitude Duration Unlikely Site specific Longterm Unlikely Site specific Long-term Mitigation Measures As for K-1 All vessels will follow the IMO standards and will be properly marked Consideration of Measures The mitigation measures are sufficient to preclude any impacts on other marine users and no residual impacts are anticipated. Cygnus A will require the presence of a standby vessel at all times. In addition there will be approximately one visit by a supply vessel per week (estimated maximum 64 per year). This increase in vessel movements is unlikely to be noticed above the current background of shipping and other vessel movements in this area (Section 10.2.2). RIA? (Y/N) Sensitivity Recoverability Importance N - - - - N - - - - Significance Report Section 10.3.5 10.3.5 CF00-00-EB-108-00001 Rev C1 Page 262 of 300

2.4 ACCIDENTAL EVENTS Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect C Water Resources C-1 Spill of chemicals or hydrocarbons (< 1 tonne) Chemical, diesel or condensate spill Potential Impact Deterioration in water quality. Likelihood Possible Spatial extent Site specific Magnitude Duration Short-term Mitigation Measures Consideration of Measures Accidental spills will be kept to a During the operation there will be chemicals on site that are not minimum through training, good permitted to be discharged e.g., oil based mud. If these or marine diesel housekeeping and through are spilt, there is the potential that they could cause localised storage/handling procedures e.g., deterioration in water quality However, the environment is sufficiently sumps, drains and bunding should dynamic and energetic to allow adequate dispersal of any spills, and catch accidental spills. tidal currents will refresh a 500m radius column of water surrounding Management controls will be in place in the spill location within one hour. Considering this and that the eliminate bunkering spills e.g., only mitigation measures will minimise the potential for any spills to occur, it bunkering during day light and in good is thought to be unlikely that there will be any significant residual impact weather. on water quality. A location specific OPEP will be in place for the development. The OPEP will detail all emergency procedures that will be in place to minimise the impacts of any spill. Pipeline connections will be minimised and welds maximised. Regular pipeline inspections will be carried out in line with the industry standard inspection frequencies. Chemical protection will be provided to prevent pipeline corrosion. RIA? (Y/N) Sensitivity Recoverability Importance N - - - - Significance Report Section 8.3.5 CF00-00-EB-108-00001 Rev C1 Page 263 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect C-2 Spill of chemicals or hydrocarbons (> 1 tonne) D Seabed Conditions D-1 Overboard loss of equipment or waste Chemical, diesel or condensate spill Dropped objects Potential Impact Deterioration in water quality. Potential for small scour around object. Likelihood Unlikely Possible Spatial extent Local Site specific Magnitude Medium Duration Short-term Short-term Mitigation Measures Consideration of Measures As for C-1 but in addition: The two worst case spill scenarios identified for the Cygnus development N - - - - GDF SUEZ E&P UK has access to Tier 1, would be loss of well containment resulting in 670m 3 of condensate 2 and 3 oil spill response capabilities released, and loss of rig inventory resulting in spillage of 750m 3 of through Oil Spill Response (OSR). marine diesel. Modelling for these scenarios indicates that both the condensate and diesel may reach 2-3km from the discharge point and GDF SUEZ E&P UK is a member of that condensate and diesel would both evaporate very rapidly, with the OSPRAG which will provide support in a diesel dispersing within 8 hours. Tidal currents will refresh a 500m well blow out event. radius column of water surrounding the discharge location within one Pipeline integrity will be ensured by precommissioning testing. to pre-impact levels if the spill is associated with a significant gas hour; although it may take slightly longer for the water column to return Control measures will be in place to release. The main components of natural gas are soluble in water and ensure rapid response to loss of are essentially not toxic (BC 2001). Minor components include benzene pipeline containment. and n-hexane which are toxic but will be rapidly dispersed and diluted by the surface currents. This will rapidly dilute within the water column which at the shallowest point of the pipeline will be 16m deep. Any degradation in water quality is anticipated to be transient and therefore this impact has not been taken forward for residual impact assessment. It is not considered that there will be any significant residual impact from the spill scenarios considered. A debris clearance survey will be It is possible that small areas of scour will occur to the leeward side of conducted at the end of each any dropped objects. The greatest potential for objects to be dropped is construction phase and any significant during construction with this very unlikely to occur during production. objects will be removed. Given the mitigation measures in place any residual impacts are likely to A dropped objects plan will be be negligible. developed to address risk of dropping objects during operations. Every reasonable measure will be taken to retrieve dropped objects. If the object cannot be retrieved, GDF will submit a PON2 form to the DECC, MCA and NFFO notifying other users of the sea of the position of the obstruction. RIA? (Y/N) Sensitivity Recoverability Importance N - - - - Significance Report Section 8.3.5 8.4.5 CF00-00-EB-108-00001 Rev C1 Page 264 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section D-2 Spill of chemicals or hydrocarbons (< 1 tonne) Chemical, diesel or condensate spill Sediment contamination Unlikely Site specific Short-term As for C-1 Spills of diesel and condensate < 1 tonne will rapidly evaporate and disperse and are not expected to reach the seabed. There is the potential that some chemicals used during construction and production may be toxic and could cause localised contamination of sediments if they were to accidentally enter the sea. However, the environment is sufficiently dynamic and energetic to disperse any spill, minimising the potential for allowing accumulation of contaminants to higher than background concentrations. Considering this, and that the mitigation measures will minimise the potential for any spills to occur, it is thought to be unlikely that there will be any significant contamination of sediments from a spill of this size. N - - - - 8.4.5 D-3 Spill of chemicals or hydrocarbons (> 1 tonne) Chemical, diesel or condensate spill Sediment contamination Unlikely Local Short-term As for C-2 Sediments may become contaminated if a breach of the pipeline Y occurred or in the instance of a loss of well control. The potential pipeline failure frequency for both the intra-field and the export pipelines has been calculated as 0.0057 failures per year (Section 7.2). If a breach were to occur, the sediments over the breach may be mobilised or trap gas. Sediments in the immediate vicinity of a pipeline breach or a loss of well control may become contaminated with hydrocarbons from gas or condensate. The ratio of gas to condensate in the pipelines is low (1.9bbls/mmscf) and the high proportion of light fractions within the condensate mean it is readily biodegradable. The high energy environment of the area also indicates that any spill will be rapidly dispersed over a wider area, reducing concentrations at the site of impact. The generally low background concentrations of THC and PAHs in sediments in the project area indicate that any change is unlikely to be sufficient to alter the classification of sediments from unpolluted. It is therefore considered that there will be a low residual impact on sediments. Moderate High - 8.4.5 E - Plankton E-1 Spill of chemicals or hydrocarbons (< 1 tonne) Chemical, diesel or condensate spill Release of gas Potential toxic effects. Possible Site specific Short-term As for C-1 C-1 concluded that a spill of < 1 tonne of chemicals, diesel or condensate would not have a residual impact on water quality. Some chemicals which are not permitted for discharge can be extremely toxic and plankton in the immediate vicinity of the spill may be affected. However, split materials will not be in the water column for long enough or at concentrations that are likely to pose a significant toxic effect to plankton. Although vulnerable to a change in water quality the plankton community undergoes a continual change in individuals with the surrounding waters and therefore is not considered sensitive. N - - - - 9.1.5 CF00-00-EB-108-00001 Rev C1 Page 265 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section E-2 Spill of chemicals or hydrocarbons (> 1 tonne) F Benthic Ecology Chemical, diesel or condensate spill Release of gas Potential toxic effects. Unlikely Local Short-term As for C-2 Modelling demonstrates that a spill of condensate or diesel will be evaporated or dispersed within 8 hours. Concentrations of hydrocarbons may reach levels that pose a significant toxic effect to plankton, but this is likely to be transient, returning to background concentrations within a few tidal cycles. Although vulnerable to a change in water quality the plankton community undergoes a continual change in individuals with the surrounding waters and therefore is not considered sensitive. N - - - - 9.1.5 F-1 Overboard loss of equipment or waste Dropped objects Physical damage to individuals Possible Site specific Short-term As for D-1 The overboard loss of equipment or waste is likely to kill individuals directly underneath the object and potentially movement of sediments may smoother those in very close proximity. The benthic community is typical of the sandbank habitat being a moderately disturbed population with relatively few species and low abundance. No rare or protected species were identified in the baseline surveys (Gardline Environmental 2011a,b,c). Any impacts will be restricted to a few individuals and not felt on the population level. N - - - - 9.2.5 F-2 Spill of chemicals or hydrocarbons (< 1 tonne) Chemical, diesel or condensate spill Release of gas Potential toxic effects Possible Site specific Short-term As for C-1 There is the potential that some chemicals used during construction and production may be toxic and could cause localised toxic effects in benthic communities if they were to enter the sea close to the seabed. However, the environment is sufficiently dynamic and energetic to disperse any spill, minimising the toxic potential. Considering this, and that the mitigation measures will minimise the potential for any spills to occur, it is thought to be unlikely that there will be any significant impacts on the benthic community from a spill of this size. N - - - - 9.2.5 CF00-00-EB-108-00001 Rev C1 Page 266 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section F-3 Spill of chemicals or hydrocarbons (> 1 tonnes) Chemical, diesel or condensate spill Release of gas Potential toxic effects Unlikely Local Short-term As for C-2 Modelling demonstrates that the worst case spill scenarios identified for the development of condensate or diesel will evaporate or disperse within 8 hours. As both diesel and condensate are lighter than water they will typically float on the surface rather than pool on the seabed, minimising the risk to benthic communities. Any components that settle to the seabed will be naturally biodegraded by microbes within one to two months. The high energy environment of the area also indicates that any spill will be rapidly dispersed over a wider area, reducing concentrations at the site of impact. Elevated concentrations of hydrocarbons may be noticeable in sediments close to the discharge point, which in turn could be toxic to benthic species. However, given the low background concentrations of THC & PAHs in sediments in the project area (see Section 8.4.2) any change is unlikely to be sufficient to change the classification of sediments from unpolluted, and toxic effects on benthic ecology are expected to be limited. If the spill is at the seabed i.e., from a well blow out, there is the potential that hydrocarbon concentrations may reach a level that is toxic to benthic species. The benthic community is typical of a moderately disturbed community (Section 9.2.3) and recovery after an impact of this kind is expected within three months to two years. It is therefore considered that there may be a localised low residual impact. Y - - 9.2.5 G-Fish and Shellfish G-1 Spill of chemicals or hydrocarbons (< 1 tonne) Chemical, diesel or condensate spill Potential toxic effects, which may affect recruitment and stock viability. Possible Site specific Short-term As for C-1 C-1 concluded that a spill of < 1 tonne of chemicals, diesel or condensate would not have a residual impact on water quality. Some chemicals which are not permitted for discharge can be extremely toxic and adults, larvae and eggs in the immediate vicinity of the spill may be affected. However, split materials will not be in the water column for long enough or at concentrations that are likely to pose a significant toxic effect to the community structure as a whole. Considering this, and that the mitigation measures will minimise the potential for any spills to occur, it is thought to be unlikely that there will be any significant impacts on finfish and shellfish from a spill of this size. N - - - - 9.3.5 CF00-00-EB-108-00001 Rev C1 Page 267 of 300

Determination of Potential Impact Consideration of Mitigation Measures RIA Section Project Activity Aspect Potential Impact Likelihood Spatial extent Magnitude Duration Mitigation Measures Consideration of Measures RIA? (Y/N) Sensitivity Recoverability Importance Significance Report Section G-2 Spill of chemicals or hydrocarbons (> 1 tonnes) Chemical, diesel or condensate spill Potential toxic effects, which may affect recruitment and stock viability. Unlikely Local Short-term As for C-2 Modelling demonstrates that the worst case spill scenarios identified for the development of condensate or diesel will evaporate or disperse within 8 hours. In the instance of a pipeline breach the main components of natural gas are sparingly soluble in water and are essentially not toxic (BOC 2001), although minor components include potentially toxic chemical species. Eggs and juveniles are most vulnerable to toxicity, and fish and shellfish will be vulnerable to toxic effects from gas and condensate dissolved in the water column. However tidal currents will refresh a 500m radius column of water surrounding the discharge location within one hour and the rapid dispersion and evaporation of condensate and diesel will minimise the impacts. There may be fatalities local to the spill or breach, although adults are likely to avoid the area. If the incident occurred during particularly sensitive periods, it is possible that recruitment for that year could be affected, however given the size of the spawning and nursery grounds within the SNS, it is unlikely that this will be seen at population level. It is therefore considered that the residual impact will be low. Y - - 9.3.5 G-3 Overboard loss of equipment or waste Dropped objects Smothering/ fatality Possible Site specific Short-term As for D-1 The overboard loss of equipment or waste may cause physical harm to sessile individuals and suspension of sediments may smoother benthic eggs or juveniles in very close proximity. The greatest potential for objects to be dropped is during construction with this very unlikely to occur during production. Given that large areas of the SNS are used for spawning and nursery grounds, it is unlikely that a small disruption at the development site will have an impact on stock viability or population levels. Considering the mitigation measures in place any residual impacts are likely to be negligible. N - - - - 9.3.5 CF00-00-EB-108-00001 Rev C1 Page 268 of 300

H - Seabirds H-1 Spill of chemicals or hydrocarbons (< 1 tonnes) Chemical, diesel or condensate spill Smothering. Potential toxic effects. Unlikely Site specific Short-term As for C-1 Accidental spills of chemicals will be rapidly diluted and dispersed with the marine environment. Uptake of toxic chemicals by plankton can have effects throughout the food chain, either as a result of direct mortality of food species or through transmission of bio accumulating chemicals to higher trophic levels. Released gas will be rapidly diluted and dispersed and levels in the atmosphere are unlikely to reach toxic levels. This level of spill would rapidly dilute and disperse within the energetic marine environment and will not pose a significant toxic potential to individuals. N - - - - 9.4.5 H-2 Spill of chemicals or hydrocarbons (> 1 tonnes) Chemical, diesel or condensate spill Smothering. Potential toxic effects. Unlikely Local Medium Short-term As for C-2 Further details of prevention, control and remediation measures are provided in Section 9.4.4 Modelling demonstrates that the worst case spill scenarios identified for the development of condensate or diesel will evaporate or disperse within 8 hours and will only reach 2-3km from the spill point. Feathers of seabirds landing on the water may become contaminated with hydrocarbons, which in turn may be ingested. Seabird vulnerability to hydrocarbon pollution is high to very high between March and May and September to November. Should a spill occur during one of these sensitive periods an intervention response may be required to minimise the risk of smothering and species injury. It is therefore considered that the residual impact would be moderate. Y Moderate Moderate Moderate Medium 9.4.5 I Marine Mammals I-1 Spill of chemicals or hydrocarbons (< 1 tonnes) Chemical, diesel or condensate spill Potential toxic effects. Smothering Unlikely Site specific Short-term As for C-1 Accidental spills of chemicals will be rapidly diluted and dispersed with the marine environment. Tidal currents will refresh a 500m radius column of water surrounding the discharge location within one hour. Discharged materials will not be present within the water column for long enough or at concentrations that are likely to pose a significant toxic or smothering threat to marine mammals. Concentrations outside the immediate discharge area/time will be close to background or undetectable. N - - - - 9.5.5 CF00-00-EB-108-00001 Rev C1 Page 269 of 300

I-2 Spill of chemicals or hydrocarbons (> 1 tonnes) Chemical, diesel or condensate spill Potential toxic effects. Smothering Unlikely Local Short-term As for C-2 Further details of prevention, control and remediation measures are provided in Section 9.4.4 Released gas will be rapidly diluted and dispersed in the water column Y and atmosphere and levels in both mediums are unlikely to reach toxic levels that would affect marine mammals. Condensate or diesel spills may cause eye or skin irritation or respiratory problems in marine mammals. Although marine mammal abundances are typically low in the SNS there are resident populations of harbour porpoise and white-beaked dolphins in the project area. It was identified that the two worst case spill scenarios during construction would be loss of well containment resulting in 670m 3 of condensate released, and loss of rig inventory resulting in spillage of 750m 3 of marine diesel. Modelling for these scenarios indicates that both the condensate and diesel may reach 2-3km from the discharge point and that condensate and diesel would both evaporate very rapidly, with the diesel dispersing within 8 hours. The mitigation measures in place minimise the potential for a spill, however should a spill occur an intervention response may be required to minimise the risk of species injury. - - 9.5.5 J Protected Sites and Species J-1 Overboard loss of equipment or waste Dropped objects Could affect the integrity of the protected feature Possible Site specific Short-term As for D-1 The development area is within the Dogger Bank csac which has been designated on account of its sandbank feature, however the highly energetic nature of the area indicates that it is not particularly sensitive to physical disturbance (Gardline 2011a,b,c). It is possible that small areas of scour will occur to the leeward side of any dropped objects. The greatest potential for objects to be dropped is during construction with this very unlikely to occur during production. Given the mobile nature of the sediments and the mitigation measures in place any residual impacts are likely to be negligible. N - - - - 9.6.5 J-2 Spill of chemicals or hydrocarbons (< 1 tonnes) Chemical, diesel or condensate spill Smothering Potential effects on integrity of a protected site Unlikely Site specific Short-term As for C-1 The project area is within the Dogger Bank csac designated for its sandbank feature and also has populations of harbour porpoise, and the occasional occurrence of common seals and grey seals. The potential impact of a spill on marine mammals has been assessed in Section I-1 above. The potential impact on the sediment of the sandbank has been assessed in D-2. It is considered that, with the mitigation measures in place, there will be no significant residual impact on the protected site as a result of a spill of this size. N - - - - 9.6.5 CF00-00-EB-108-00001 Rev C1 Page 270 of 300

J-3 Spill of chemicals or hydrocarbons (> 1 tonnes) Chemical, diesel or condensate spill Smothering Potential effects on integrity of a protected site. Unlikely Local Short-term As for C-2 The project area is within the Dogger Bank csac designated for its Y sandbank feature and also has populations of harbour porpoise, and the occasional occurrence common seals and grey seals. The potential impact of a spill on marine mammals has been assessed in I-2 above. The potential impact on the sediment of the sandbank has been assessed in D-3. As discussed in D-3 sediments over the breach may be mobilised, trap gas or become contaminated with hydrocarbons. Any effects are expected to be minimal and confined to a small area around the breach. The overall integrity of the Dogger Bank will not be affected. A release of gas will not affect interest features species - see I-2. Moderate High - 9.6.5 K Commercial Fishing K-1 Overboard loss of equipment or waste Dropped objects Could snag fishing gear. Possible Site specific Shortterm As for D-1 The industry standard best practise measures are considered to be sufficient to reduce the impact on fishing vessels in the area. As such, they have not been taken forward for residual impact significance assessment. N - - - - 10.1.5 K-2 Spill of chemicals or hydrocarbons (< 1 tonnes) Chemical, diesel or condensate spill Potential decrease in catch if stocks affected Unlikely Site specific Short-term As for C-1 Accidental spills of chemicals will be rapidly diluted and dispersed with the marine environment. Tidal currents will refresh a 500m column of water surrounding the discharge location within one and a half hours. Section G-1 has assessed the potential impact of a spill of this size on the fish populations and it is not considered that there will be a significant residual impact, therefore there will be no impact on fishing activities in the area. N - - - - 10.1.5 K-3 Spill of chemicals or hydrocarbons (> 1 tonnes) Chemical, diesel or condensate spill Potential decrease in catch if stocks affected Exclusion from fishing grounds Unlikely Local Medium Short-term As for C-2 Section G-3 has assessed the potential impact on fish and shellfish and identified that the residual impact will be low and that there is unlikely to be an effect at wild population levels. It is therefore unlikely that there will be a residual impact in fish availability for fishing activities. The presence of a spill may require that fishing vessels are excluded from an area for a short period during any clean-up activities. Modelling of the two worst case spill scenarios has indicated that both the condensate and diesel may reach 2-3km from the spill point and that condensate and diesel would both evaporate very rapidly, with the diesel dispersing within 8 hours. This is not a significant proportion of the SNS fishing grounds and it is considered unlikely that there would be a significant loss of income associated with any cleanup activities. It is possible that there would be a loss of market confidence therefore it is considered that the residual impact of a spill of this size would be low. Y - - 10.1.5 CF00-00-EB-108-00001 Rev C1 Page 271 of 300

L Shipping and Navigation L-1 Spill of chemicals and hydrocarbons (> 1 tonne) L-2 Overboard loss of equipment or waste Chemical or hydrocarbon spill Dropped objects M Other Marine Users M-1 Overboard loss of equipment or waste M-2 Spill of chemicals or hydrocarbons (> 1 tonnes) N - Archaeology N-1 Overboard loss of equipment or waste Dropped objects Chemical, diesel or condensate spill Dropped objects Damage to vessels Restrictions on shipping lanes Could cause hazard to shipping Could cause hazard to shipping Restricted access Could disturb currently unknown maritime archaeological features Unlikely Local Short-term Possible Site specific Shortterm Unlikely Site specific Shortterm Unlikely Possible Local Site specific Short-term Short term As for C-2 As for D-1 As for D-1 As for C-2 As for D-1 Modelling of the two worst case spill scenarios (670m 3 of condensate or 750m 3 of marine diesel) has indicated that the condensate and diesel may reach 2-3km (1.1 nm to 1.6 nm) from the discharge point and that they would both evaporate very rapidly, with the diesel dispersing within 8 hours. Three shipping routes are within 1.6 nm of Cygnus A and four are within 1.6nm of Cygnus B. These routes are not heavily used with a total of 124 ships per year using those close to Cygnus A, and 228 per year using those near Cygnus B. It is possible that a ship passing at the time of the incident will have to re-route around the spill or that a shipping lane may be closed for a short period during spill response operations. The relatively small nature of the estimated spills, the rapid dispersion and evaporation and the frequency of use of the shipping routes indicates that the closures would be short term and temporary and are likely to have a low residual impact. The industry standard best practise measures are considered to be sufficient to reduce the impact on shipping in the area. As such, they have not been taken forward for residual impact significance assessment. The industry standard best practise measures are considered to be sufficient to reduce the impact on other marine users in the area. As such, they have not been taken forward for residual impact significance assessment. Y - - N - - - - N - - - - The presence of a spill may require that marine users are excluded from an area for a short period during any cleanup activities. Modelling of the two worst case spill scenarios during construction (670m 3 of condensate or 750m 3 of marine diesel) has indicated that both the condensate and diesel may reach 2-3km from the spill point and that condensate and diesel would both evaporate very rapidly, with the diesel dispersing within 8 hours. The size of the area that will require exclusion will not be significant and the period of exclusion will be temporary therefore it is not considered that there will be any residual impacts. N - - - - No archaeological features other than the wreck, were identified during the site surveys (Gardline Environmental 2011a,b,c). The mitigation measures in place will ensure that damage to any previously undiscovered archaeological feature is likely to be minimised and will be properly reported. N - - - - 10.2.5 10.2.5 10.3.5 10.3.5 10.4.5 CF00-00-EB-108-00001 Rev C1 Page 272 of 300

3.1 DRILLING CHEMICALS FOR ONE WELL 36" Section Appendix 3 - Chemical Summary Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) Caustic Soda E 3 3 Citric Acid E PLO 2 2 DUO-VIS Gold 2 2 Dynared Seepage Control Fibre E PLO 2 2 EMI-2224 Gold 1 1 Flowzan Biopolymer E PLO 2 2 GUAR GUM E PLO 9 9 LIME E PLO 1 1 M-I BAR (All Grades) E PLO 180 180 M-I GEL E PLO 90 90 Mica E PLO 2 2 Nutshells All Grades E PLO 2 2 POLYPAC All Grades E PLO 4 4 POTASSIUM CHLORIDE E PLO 150 150 Potassium Chloride Brine E PLO 150 150 SAFE-CARB (ALL GRADES) E PLO 18 18 Safe-cide Gold 0.5 0.5 SAPP E PLO 2 2 Soda Ash E PLO 3 3 Sodium Bicarbonate E PLO 2 2 Sugar E PLO 2 2 17 ½ Section Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) Caustic Soda E 3 3 Citric Acid E PLO 2 2 DUO-VIS Gold 4 4 Dynared Seepage Control Fibre E PLO 4 4 EMI-2224 Gold 1 1 Flowzan Biopolymer E PLO 4 4 GUAR GUM E PLO 13 13 KWIK-SEAL (All Grades) E 4 4 CF00-00-EB-108-00001 Rev C1 Page 273 of 300

Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) LIME E PLO 2 2 M-I BAR (All Grades) E PLO 320 320 M-I GEL E PLO 240 240 Mica E PLO 4 4 Nutshells All Grades E PLO 4 4 POLYPAC All Grades E PLO 7 7 POTASSIUM CHLORIDE E PLO 10 10 Potassium Chloride Brine E PLO 300 300 SAFE-CARB (ALL GRADES) E PLO 24 24 Safe-Cide Gold 2 2 SAPP E PLO 2 2 Soda Ash E PLO 3 3 Sodium Bicarbonate E PLO 2 2 Sugar E PLO 2 2 12 ¼ Section Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) CALCIUM CHLORIDE (ALL GRADES) E PLO 120 0 Calcium Chloride Brine E PLO 1170 0 Caustic Soda E 1 0 Citric Acid E PLO 2 0 DF1 E 855 0 DUO-TEC Gold 1 0 DUO-VIS Gold 1 0 Dynared Seepage Control Fibre E PLO 5 0 ECOTROL RD E SUB 5 0 FORM-A-BLOK Gold SUB 8 0 G-SEAL PLUS E PLO 5 0 Ironite Sponge E PLO 2 0 Koplus LL E PLO 8 0 Koplus LO Gold 8 0 KWIK-SEAL (ALL GRADES) E 5 0 LIME E PLO 36 0 M-I BAR (All Grades) E PLO 1480 0 Mica E PLO 5 0 Nutshells All Grades E PLO 5 0 CF00-00-EB-108-00001 Rev C1 Page 274 of 300

Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) POTASSIUM CHLORIDE E PLO 20 0 Potassium Chloride Brine E PLO 35 0 SAFE-CARB (ALL GRADES) E PLO 22 0 SAFE-SCAV HSB Gold 2 0 SAFE-SURF E Gold SUB 4 0 SAFE-SURF NS Gold SUB 4 0 SAPP E PLO 1 0 Sodium Bicarbonate E PLO 3 0 Soltex Additive Gold SUB 5 0 Sugar E PLO 2 0 TRUVIS E 23 0 VERSACLEAN CBE B SUB 30 0 Versaclean FL B SUB 30 0 Versaclean VB B SUB 2290 0 VERSAGEL HT E 17 0 VERSATROL M E SUB 15 0 VG-Supreme E 4 0 WT-1040 Gold 2 0 8 1/2 Section (OBM Option) Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) CALCIUM CHLORIDE (ALL GRADES) E PLO 36 0 Calcium Chloride Brine E PLO 153 0 Caustic Soda E 1 0 Citric Acid E PLO 2 0 DF1 E 450 0 DUO TEC Gold 1 0 DUO-VIS Gold 1 0 Dynared Seepage Control Fibre E PLO 5 0 ECOTROL RD E SUB 5 0 FORM-A-BLOK Gold SUB 8 0 G-SEAL PLUS E PLO 5 0 Ironite Sponge E PLO 2 0 Koplus LL E PLO 8 0 Koplus LO Gold 8 0 KWIK-SEAL (ALL GRADES) E 5 0 CF00-00-EB-108-00001 Rev C1 Page 275 of 300

Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) LIME E PLO 20 0 M-I BAR (All Grades) E PLO 408 0 Mica E PLO 5 0 Nutshells All Grades E PLO 5 0 POTASSIUM CHLORIDE E PLO 20 0 Potassium Chloride Brine E PLO 35 0 SAFE-CARB (ALL GRADES) E PLO 18 0 SAFE-SCAV HSB Gold 2 0 SAFE-SURF E Gold SUB 4 0 SAFE-SURF NS Gold SUB 6 0 SAPP E PLO 1 0 Sodium Bicarbonate E PLO 3 0 Soltex Additive Gold SUB 5 0 Sugar E PLO 2 0 TRUVIS E 25 0 VERSACLEAN CBE B SUB 14 0 Versaclean FL B SUB 726 0 Versaclean VB B SUB 20 0 VERSAGEL HT E 10 0 VERSATROL M E SUB 12 0 VG-Supreme E 4 0 WT-1040 Gold 2 0 8 1/2 Section (WBM Option) Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) Caustic Soda E 3 3 Citric Acid E PLO 4 4 CONQOR 404NS Gold 9 9 DRILLING STARCH E PLO 33 33 Drispac Plus Superlo Polymer E 10 10 DUO-VIS Gold 9 9 Dynared Seepage Control Fiber E PLO 6 6 EMI-2224 Gold 2 2 FLO-TROL E PLO 10 10 Flowzan Biopolymer E PLO 9 9 Glydril HC Gold PLO 80 80 G-SEAL PLUS E PLO 5 5 CF00-00-EB-108-00001 Rev C1 Page 276 of 300

Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) Ironite Sponge E PLO 4 4 KWIK-SEAL (ALL GRADES) E PLO 6 6 LIME E PLO 1 1 M-I BAR (All Grades) E PLO 1725 1725 Mica E PLO 20 20 Nutshells All Grades E PLO 20 20 POLYPAC All Grades E PLO 13 13 POTASSIUM CHLORIDE E PLO 40 40 Potassium Chloride Brine E PLO 1125 1125 SAFE-CARB (ALL GRADES) E PLO 30 30 Safe-cide Gold 3 3 SAFE-SCAV HSB Gold 2 2 SAFE-SURF E Gold SUB 4 4 SAPP E PLO 1 1 SODA ASH E PLO 2 2 Sodium Bicarbonate E PLO 2 2 Sodium Chloride Brine E PLO 2223 2223 Sodium Chloride Powder (Salt PVD or Granular Salt) E PLO 585 585 Sugar E PLO 1 1 6 Section (OBM Option) Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) CALCIUM CHLORIDE (ALL GRADES) E PLO 128 0 Calcium Chloride Brine E PLO 200 0 Caustic Soda E 1 0 Citric Acid E PLO 2 0 DF1 E 540 0 DUO-VIS Gold 1 0 Dynared Seepage Control Fiber E PLO 5 0 ECOTROL RD E SUB 5 0 FORM-A-BLOK Gold SUB 8 0 G-SEAL PLUS E PLO 5 0 Ironite Sponge E PLO 2 0 Koplus LL E PLO 8 0 Koplus LO Gold 8 0 KWIK-SEAL (ALL GRADES) E 5 0 CF00-00-EB-108-00001 Rev C1 Page 277 of 300

Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) LIME E PLO 32 0 M-I BAR (All Grades) E PLO 400 0 Mica E PLO 5 0 Nutshells All Grades E PLO 5 0 POTASSIUM CHLORIDE E PLO 20 0 Potassium Chloride Brine E PLO 35 0 SAFE-CARB (ALL GRADES) E PLO 800 0 SAFE-SCAV HSB Gold 2 0 SAFE-SURF E Gold SUB 4 0 SAFE-SURF NS Gold SUB 6 0 SAPP E PLO 1 0 Sodium Bicarbonate E PLO 3 0 Soltex Additive Gold SUB 5 0 Sugar E PLO 2 0 TRUVIS E 20 0 VERSACLEAN CBE B SUB 40 0 Versaclean FL B SUB 20 0 Versaclean VB B SUB 20 0 VERSAGEL HT E 20 0 VERSATROL M E SUB 16 0 VG-Supreme E 4 0 WT-1040 Gold 2 0 6 Section (WBM Option) Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) Citric Acid E PLO 4 4 CONQOR 404NS Gold 9 9 DUO-VIS Gold 12 12 Dynared Seepage Control Fibre E PLO 6 6 EMI-2224 Gold 3 3 FLO-TROL E PLO 39 39 FLO-VIS PLUS Gold 12 12 Flowzan Biopolymer E PLO 6 6 FORM-A-BLOK Gold SUB 8 8 G-SEAL PLUS E PLO 5 5 Ironite Sponge E PLO 6 6 CF00-00-EB-108-00001 Rev C1 Page 278 of 300

Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) KLA-STOP NS Gold 40 40 Koplus LL E PLO 8 8 KWIK-SEAL (ALL GRADES) E PLO 6 6 MAGNESIUM OXIDE E PLO 3 3 Nutshells All Grades E PLO 20 20 POTASSIUM CHLORIDE E PLO 141 141 Potassium Chloride Brine E PLO 1035 1035 SAFE-CARB (ALL GRADES) E PLO 700 700 Safe-cide Gold 3 3 SAFE-SCAV HSB Gold 4 4 SAFE-SCAV NA E 3 3 SAPP E PLO 1 1 SODA ASH E PLO 3 3 Sodium Bicarbonate E PLO 3 3 Sodium Chloride Brine E PLO 2400 2400 Sodium Chloride Powder (Salt PVD or Granular Salt) E PLO 225 225 CF00-00-EB-108-00001 Rev C1 Page 279 of 300

3.2 CEMENTING CHEMICALS Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) 95% Calcium Chloride S002 E PLO 12.84 1.28 AccuSET D197 Gold 21.75 2.17 Antifoam Agent D175A Gold SUB 0.21 0.02 Antifoaming Agent D206 Gold SUB 0.51 0.16 Antisedimentation Agent B18 E PLO 21.52 2.15 Anti-Settling Agent D153 E PLO 79.02 41.08 Bentonite Extender D20 E PLO 0.75 0.21 Class G Oilwell (Portland) Cement (CEBO) E PLO 1610.76 161.08 D095 Cement Additive Total E PLO 2.89 0.76 D600G GASBLOK* Gas Migration Control Additive Gold SUB 22.53 7.11 Dispersant B213 Gold 20.60 1.50 Dye B275 Gold 0.63 0.24 Environmentally Friendly Dispersant B165 E PLO 7.76 0.78 GASBLOK* LT D500 Gold SUB 36.17 1.93 Granulated Salt D44 E PLO 81.60 9.60 Liquid Accelerator D77 E PLO 11.14 1.12 Liquid Antifoam B143 Gold 3.64 1.10 Liquid Antifoam B411 Gold 3.65 1.10 Liquid Retarder D81 E PLO 12.56 2.89 MI-BAR (MI Drilling Fluids) E PLO 215.44 64.63 Mid-Temp Retarder-L D801 E PLO 4.65 1.31 Mutual Solvent U66 Gold 14.99 1.10 Silica Flour (CEBO) E PLO 465.75 46.58 Silicate Additive D75 E PLO 31.08 3.11 Surfactant B323 Gold 12.24 3.34 Surfactant D191 Gold 12.24 3.34 UNIFLAC-L D168 Gold 16.43 1.64 Viscosifier for MUDPUSH II spacer B174 E PLO 3.50 1.05 CF00-00-EB-108-00001 Rev C1 Page 280 of 300

3.3 COMPLETION AND OTHER CHEMICALS Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) Completion Chemicals CALCIUM CHLORIDE (ALL GRADES) E PLO 20 20 Calcium Chloride Brine E PLO 1300 1300 Caustic Soda E 1.5 1.5 Citric Acid E PLO 1 1 DF1 E 100 0 DRILLING STARCH E PLO 2 2 DUO-VIS Gold 5 5 Dynared Seepage Control Fibre E PLO 2.5 2.5 EMI 2224 Gold 2 2 HEC E PLO 5 5 KI-3924 Silver SUB 0.05 0.05 KWIK-SEAL (All Grades) E 2 2 LIME E PLO 1.5 1.5 MAGNESIUM OXIDE E PLO 1 1 MEG E PLO 10 0 Methanol E PLO 4 0 M-I BAR (All Grades) E PLO 50 50 Plugsal E PLO 2 2 Plugsal-X E PLO 2 2 POLYPAC - All Grades E PLO 4.5 4.5 Potassium Chloride Brine E PLO 432 432 SAFE COR 220X Gold 10 10 SAFE-CARB (ALL GRADES) E PLO 15 15 SAFE-CIDE Gold 2 2 SAFE-COR EN Gold 20 20 SAFE-SCAV CA Gold 2 2 SAFE-SCAV HSB Gold 1 1 SAFE-SCAV NA E PLO 2 2 SAFE-SURF E Gold SUB 8 0 SAFE-SURF NS Gold SUB 16 0 SI-414N Gold 1 1 Soda Ash E PLO 0.5 0.5 Sodium Chloride Brine E PLO 1150 1150 CF00-00-EB-108-00001 Rev C1 Page 281 of 300

Chemical Name HQ Chemical Label Code Estimated Use (tonnes) Estimated Discharge (tonnes) Sodium Chloride Powder (Salt PVD or Granular Salt) E PLO 40 40 Sugar E PLO 1 1 Frac Chemicals 100 mesh Sand E PLO 9.1 9.1 BA-20 E PLO 33.8 16.9 CL-28E E 24.7 12.4 GasPerm 1000 Gold SUB 16.7 8.4 GEL-STA STABILIZER E PLO 18.2 9.1 HII-124F E PLO 22.9 11.5 K-38 E PLO 1 0.5 KCl E PLO 236.3 118.2 LGC-1M E 452.9 226.5 LGC-IIM E 449 224.5 LOSURF-400 Gold SUB 15.2 7.6 MO-67 E 38.6 19.3 NF-6 Gold 16.9 8.5 OPTIFLO-III Gold SUB 1.9 1 OptiProp Coated Ceramic Proppant Gold SUB 1269.9 1269.9 Sodium Hypochlorite E 0.1 0.1 SP-BREAKER D 1.9 1 Starcide Gold 0.3 0.2 VICON NF BREAKER B 25.6 12.8 CF00-00-EB-108-00001 Rev C1 Page 282 of 300

Appendix 4 - Oil Spill Modelling 4.1 INTRODUCTION This report is to support the Environmental Statement for the and to meet the latest Department of Energy and Climate Change (DECC) guidance letter regarding hydrocarbon release assessment released to industry on the 23 December 2010. The guidance states that the ES assessment of potential impacts from hydrocarbon releases must be extended to match the scope of the recently amended oil pollution emergency plan (OPEP) guidelines. 4.2 CYGNUS FIELD DEVELOPMENT The Cygnus Field development is a medium-sized gas development located in the UKCS Blocks 44/11a and 44/12a, in the Southern North Sea (SNS). It lies approximately 155km north-east of the north Norfolk (UK) coastline and 35km west of the UK/Netherlands median line. The development comprises: The Cygnus Alpha (Cygnus A) Hub, a permanently manned main platform with central production, processing and accommodation facilities. The Cygnus Bravo (Cygnus B) satellite wellhead platform, a not permanently attended installation (NPAI) tied back to the Cygnus A central facility. The drilling of ten horizontal wells A c.51km 24-inch export pipeline tied in to the existing ETS pipeline A 5.9km 12-inch infield pipeline and umbilical between Cygnus A and Cygnus B located WNW of Cygnus A Associated subsea infrastructure Operation and production of the field for an expected 35 years Cygnus A and B lie within the Dogger Bank candidate Special Area of Conservation (csac) in water depths of 22m. The boundaries of the csac lie 40km to the east and 35km to the south of the platforms. The export pipeline passes through the csac to the boundary 40km to the south-west of Cygnus A and extends 10km beyond this boundary. Water depths along the route range from 15.7m on top of the Dogger Bank to 48.8m at the ETS pipeline tie-in point. A total of ten wells are to be drilled as part of the field development, five wells at Cygnus A and five wells at Cygnus B. The coordinates for the wells are provided in Section 1.2.2. Drilling will be conducted from a jack-up drilling rig similar to the ENSCO 100. GDF SUEZ E&P UK will submit an OPEP to the DECC Offshore Inspectorate for approval to cover the drilling and production activities. The OPEP will comply with the requirements of The Offshore Installations (Emergency Pollution Control) Regulations 2002 and The Merchant Shipping (Oil Pollution Preparedness, Response Co-operation Convention) Regulations 1998 and take into consideration recent revised guidance from the DECC following the Gulf of Mexico Macondo incident. 4.3 WORST CASE OIL SPILL MODELLING Three spill scenarios have been identified within the project scope, which represent the worst case spill scenarios of condensate and diesel: Complete loss of well control (e.g., well blow out) 2.8m 3 /hour of condensate (for the purposes of modelling a figure of 670m 3 has been used which represents the total quantity spilt after ten days) Total loss of containment of the diesel inventory on the rig as a result of a collision 750m 3 (578 tonnes) of marine diesel Loss of integrity to the gas export pipeline 14,146m 3 of gas containing 0.151m 3 of condensate CF00-00-EB-108-00001 Rev C1 Page 283 of 300

As the potential spill of condensate from the gas export pipeline is smaller than that which would occur from the loss of well control it has not been modelled. Oil Spill Response (OSR) was commissioned to undertake oil spill modelling of the first tw o scenarios using OSIS 5.0 software (OSR 2011). The Oil Spill Information System (OSIS), developed by BMT Cordah Ltd, is an oil spill model that predicts the movement of oil on the water surface and the distribution of oil in the marine environment. It is a fully validated and calibrated oil spill model based upon extensive research conducted by Warren Spring Laboratories and subsequently AEA Technology plc. The weathering model within OSIS has been validated against controlled actual spills at sea and real spill events supported with laboratory calibration. The model has a number of limitations that should be considered when interpreting the results: Modelling results are for guidance purposes only and response strategies should not be based solely on modelling results alone. The resolution / quality of tidal and oceanic current data varies between regions and models. As with any other model, results are dependent on the quality of the environmental parameters and scenario inputs used. The properties of the oil in the model s database may not precisely match those of the product spilled. If the same scenario was conducted in another oil spill modelling programme, with identical parameters and inputs, the results may show a degree of variance. This is expected as the different fate and weathering models have been developed and programmed independently. In addition the following assumptions were made when commissioning the models: An air temperature of 13 C and sea temperature of 10 C were used as representative of temperatures in June. Wind data was taken from the Met Office European model (54.6 N 2.3 E) for the period 1991 2000 and from the Met Office UK Water Model for the period 2000-2008. The June wind rose was selected to match the start date of the spring tide. The principal tidal current data used was used was the High Resolution Continental Shelf Model (CS20) from the Proudman Oceanographic Laboratory (www.pol.ac.uk/appl/supply.html). The 24 th June 2013 was used as the start date of the model. This is the first high spring tide currently forecast after the May 2013 drilling start date. A start date at a high spring tide represents a period when tides would be moving at a greater rate than usual and therefore potentially demonstrates the greatest movement of surface oil. The oils specified for modelling were marine diesel and Cygnus condensate. Cygnus condensate is not in the OSIS oil database but oil matching was undertaken to find a suitable substitute condensate within the OSIS database. Tormore condensate (API 48.4293, density 0.78642) was selected as this condensate has the most similar characteristics to Cygnus condensate. 4.4 SPILL SCENARIOS AND MODELLING RESULTS The loss of well control scenario was modelled using two types of model: Stochastic - This type of modelling is carried out for the most persistent type of hydrocarbon within the project scope. A stochastic model, also known as a probability model shows the probability distribution for potential impacts of a hydrocarbon spill, over a defined time. The model uses historical wind data to run a series of trajectories for all wind directions i.e., the 12 points of the compass, and then calculates the probability of a spill following any particular trajectory. The contours indicate the probability of the spill spreading to the extent shown for a particular wind direction. The results for each of the 12 wind directions are overlain in to one final diagram which indicates the probability of oil being found at a distance from the spill rather than the total extent of a single spill. This type of modelling is an important tool for determining the areas of coastline that could potentially be affected by a spill and therefore the best locations to place oil spill response equipment. However, this type of diagram is typically the most misunderstood part of an Environmental Statement or Oil Pollution Emergency Plan. CF00-00-EB-108-00001 Rev C1 Page 284 of 300

The most important thing to note is that it does not illustrate the extent of the area which will be affected if a spill occurs. Trajectory - A trajectory or deterministic model is used to predict the route of a hydrocarbon slick over time and under defined weather and current conditions. UK legislation requires that two trajectory models are undertaken for each spill scenario investigated by the oil and gas industry; one trajectory using a 30 knot wind blowing towards the nearest stretch of UK coastline; and one trajectory using a 30 knot wind blowing towards the closest international boundary. In accordance with DECC guidelines on oil spill modelling, one stochastic and two trajectory models were run for the loss of well control scenario. Although the estimated time to mobilise and drill a relief well is 90 days, modelling using the OSIS software is not possible for this duration. Instead, the model was run for a period of 10 days, which for planning purposes is believed to be sufficient. Condensate is a light hydrocarbon and modelling over 10 days shows that any condensate released in this period will fully disperse and evaporate within this time period. Therefore, any condensate released after 10 days will not increase the extent of the area impacted by a spill. Modelling undertaken for this period of time also acts as a good indicator of beached volumes as after 10 days additional response procedures (i.e., shoreline recovery and use of dispersants) should be in place to reduce the amount of oil that will beach. In addition, one stochastic and two trajectory models were commissioned for the instantaneous loss of the diesel inventory of the drilling rig (750m 3 ). The scenarios and volumes modelled are presented in Table 4-1 below. Table 4-2 presents a summary of the modelling results as illustrated in Figures 4-1 to 4-5. For the trajectory models, the red lines show the direction of the leading edge of the spill where as the black dots show the areas which the oil is likely to spread to. Appendix Table 4-1 : Spill scenarios modelled Scenario Hydrocarbon Type of spill Quantity (m 3 ) Model run type Conditions 1 Stochastic 2 670 Trajectory 30 knot wind towards UK Total loss of well Condensate control (released over 30 knot wind towards ten days) nearest international 3 Trajectory boundary (i.e., UK/Netherlands) 4 Stochastic 5 Trajectory 30 knot wind towards UK Total loss of rig 750 Diesel inventory 30 knot wind towards (instantaneous) nearest international 6 Trajectory boundary (i.e., UK/Netherlands) Appendix Table 4-2 : Modelling results N/A N/A Scenario Model run type Fate of spill, as modelled 1 Stochastic 2 Trajectory (towards UK) Figure 4-1 There is a zero probability of condensate beaching on the coastline or crossing the UK / Netherlands international boundary. Figure 4-2 The leading edge of the spill is 1.2km from the release site. It is estimated that approximately 640m 2 of the condensate will evaporate and the remainder will disperse within the water column. No condensate will reach the coastline. CF00-00-EB-108-00001 Rev C1 Page 285 of 300

Scenario 3 Model run type Trajectory (towards international boundary) Figures 4-3 Fate of spill, as modelled The leading edge of the spill is 1.4km from the release site. It is estimated that approximately 640m 2 of the condensate will evaporate and the remainder will disperse within the water column. No condensate will cross the UK / Netherlands international boundary which would still be 37.2km from the leading edge of the spill. 4 Stochastic Figure 4-4 There is zero probability of diesel beaching on the coastline or crossing the UK/Netherlands international boundary. 4 5 Trajectory (towards UK) Trajectory (towards international boundary) Figures 4-5 The leading edge of the spill is 16.6km from the release site. Within eight hours the spill has evaporated and dispersed into the water column. Approximately 305m 3 will evaporate and 445m 3 will disperse. No diesel will beach on the UK coastline. Figures 4-6 The leading edge of the spill is 20.5km from the release site. Within eight hours the spill has evaporated and dispersed into the water column. Approximately 306m 3 will evaporate and 444m 3 will disperse. No condensate will cross the UK / Netherlands international boundary which would still be 18km from the leading edge of the spill. Appendix Figure 4-1 : Scenario 1 Condensate spill of 670m 3 over ten days from loss of well control - stochastic model a) Overview b) Detailed view Note: Plot represents the combination of spill scenarios from 12 different wind directions Probability legend Wind data CF00-00-EB-108-00001 Rev C1 Page 286 of 300

Appendix Figure 4-2 : Scenario 2 Condensate spill of 670m 3 over ten days from loss of well control trajectory towards UK coastline a) Overview b) Detailed view c) Fate of spill volume CF00-00-EB-108-00001 Rev C1 Page 287 of 300

Appendix Figure 4-3 : Scenario 3 Condensate spill of 670m 3 over ten days from loss of well control trajectory towards closest international boundary a) Overview b) Detailed view c) Fate of spill volume CF00-00-EB-108-00001 Rev C1 Page 288 of 300

Appendix Figure 4-4 : Scenario 4 Instantaneous diesel spill of 750m 3 from loss of rig inventory stochastic model Note: Plot represents the combination of spill scenarios from 12 different wind directions Probability legend Wind data Appendix Figure 4-5 : Scenario 5 Instantaneous diesel spill of 750m 3 from loss of rig inventory trajectory towards UK coastline a) Overview b) Detailed view CF00-00-EB-108-00001 Rev C1 Page 289 of 300

c) Fate of spill volume CF00-00-EB-108-00001 Rev C1 Page 290 of 300

Appendix Figure 4-6 : Scenario 6 Instantaneous diesel spill of 750m 3 from loss of rig inventory trajectory towards closest international boundary a) Overview b) Detailed view c) Fate of spill volume CF00-00-EB-108-00001 Rev C1 Page 291 of 300

4.5 ENVIRONMENTAL IMPACT ASSESSMENT Fish An accidental spill of chemicals, diesel or hydrocarbons greater than 1 tonne was assessed as having the potential to have a residual impact of low significance. In fish life cycles the egg and juvenile stages are the most vulnerable to toxicity in the water column, as adult fish are highly mobile and generally able to avoid polluted areas. Fish and shellfish will be vulnerable to toxic effects from gas and condensate dissolved in the water column. Although, minor components of the Cygnus gas are toxic to marine animals, they will be rapidly diluted and dispersed by currents minimising their toxic potential. In general, lighter refined petroleum products such as diesel and condensate will also mix in the water column, with toxic consequences. However, they tend to evaporate quickly and do not persist. Localised fatalities may occur in the immediate vicinity of the spill, but fish are likely to avoid the area if the situation persists, and any effects are unlikely to be felt on a population level. There are particular periods of the year when fish species are more sensitive e.g., during periods of high spawning activity, and a spill during a particular sensitive period could affect recruitment for that year. However, the spawning/nursery grounds span large areas of the North Sea which should mean that long-term changes to populations are negligible. Seabirds An accidental spill of chemicals, diesel or hydrocarbons greater than 1 tonne was assessed as having the potential to have a residual impact of low significance. Seabirds that spend the majority of the time on the sea surface are most vulnerable as their feathers can become contaminated with hydrocarbons, which in turn may be ingested. Seabird vulnerability to hydrocarbon pollution is generally moderate for the year with peaks of high to very high vulnerability between April to May and September to November. However, as identified above, condensate and diesel will evaporate quickly reducing the potential for species injury. Drilling activity is scheduled to occur throughout the year and may therefore overlap at some stage with the sensitive periods for seabirds identified by the JNCC. Should a spill occur during one of these sensitive periods an intervention response may be required to minimise the risk of smothering and species injury. Mitigation measures, in the form of: management controls to eliminate bunkering spills; and the absence of heavy hydrocarbons, should prevent any sizeable spills. In addition, the development will be covered by a site -specific OPEP which will outline response actions to be undertaken to minimise the environmental impact of a spill should one occur. Marine Mammals An accidental spill of chemicals, diesel or hydrocarbons greater than 1 tonne was assessed as having the potential to have a residual impact of low significance. Cetaceans have smooth hairless skins over a thick layer of insulating blubber, so hydrocarbons are unlikely to adhere persistently or cause breakdown in isolation. A diesel or condensate spill may cause eye or skin irritation or respiratory problems in marine mammals. However, in the offshore SNS environment and particularly on the high -energy Dogger Bank, any diesel or condensate spill will begin to dissipate immediately and will fully dissipate within eight hours. Therefore, the expected contact between marine mammals and any accidental spill is predicted to be minimal. Furthermore, marine mammal abundances are typically low in the SNS, although there are resident populations of harbour porpoise and white-beaked dolphins in the project area. Mitigation measures, in the form of: management controls to eliminate bunkering spills; and the absence of heavy hydrocarbons, should prevent any sizeable spills. In addition, the development will be covered by a site-specific OPEP which will outline response actions to be undertaken to minimise the environmental impact of a spill should one occur. However, if a spill were to occur, an intervention response may be required to minimise the risk of species injury. Protected Sites An accidental spill of chemicals, diesel or hydrocarbons greater than 1 tonne was assessed as having the potential to have a residual impact of low significance. Oil spill modelling presented above illustrates that for the worst case hydrocarbon spill scenarios identified for the Cygnus development, diesel and condensate will evaporate and naturally CF00-00-EB-108-00001 Rev C1 Page 292 of 300

disperse rapidly and will not beach on any shoreline. Given the nature of the hydrocarbons present it is unlikely that the integrity of the Dogger Bank csac will be affected by a large spill. In addition, the management controls in place should prevent any sizeable spills and measures outlined in the OPEP should minimise the impact of any spill should one occur. CF00-00-EB-108-00001 Rev C1 Page 293 of 300

Appendix 5 - Seasonal Wind Roses CF00-00-EB-108-00001 Rev C1 Page 294 of 300

5.1 JANUARY CF00-00-EB-108-00001 Rev C1 Page 295 of 300

5.2 APRIL CF00-00-EB-108-00001 Rev C1 Page 296 of 300

5.3 JULY CF00-00-EB-108-00001 Rev C1 Page 297 of 300

5.4 OCTOBER CF00-00-EB-108-00001 Rev C1 Page 298 of 300

Appendix 6 - JNCC Risk Assessment Flow Charts Appendix Figure 6-1 : Risk assessment flow chart for non-trivial disturbance Source: JNCC (2010) Appendix Figure 6-2 : Risk assessment flow chart for physical injury Source: JNCC (2010) CF00-00-EB-108-00001 Rev C1 Page 299 of 300

Appendix Figure 6-9 : M-weighting functions for low-, mid-, and high-frequency cetaceans Source: Southall et al. (2007) CF00-00-EB-108-00001 Rev C1 Page 300 of 300