Environmental. effects of power. supply. Victorian Desalination Project Environment Effects Statement Volume 5. A Victorian Government project

Transcription

1 Environmental effects of power supply Victorian Desalination Project Environment Effects Statement Volume 5 A Victorian Government project

2 Contents Contents

3 Table of Contents Victorian Desalination Project Document Structure...i Volume 5 Environmental Effects of Power Supply... ii 1 Introduction Basis of the Project Description Performance Requirements Power Supply components Purpose of the new Power Supply infrastructure Power requirements Evolution of the Reference Project Connection to the grid Transmission Connection Approach Assessment of grid connections Reference Project Construction of the Reference Project Operation of the Reference Project Decommissioning of the Reference Project Variations in the EES Variations to the alignment within the investigation corridor for the transmission line Variation to location of terminal stations Options Grid connection underground Northerly alternative alignment Gas-fired power station Hybrid Options Outside scope Direct sources of renewable energy supply Interactions with the environment Characterisation of the terrestrial environment Bass Coast Strzelecki foothills and Bass Valley Alluvial plain Impact pathways for the risk and impact assessment Risk Assessment Approach for Impact Assessment Table of Contents 1

4 3.4.1 Construction activities and risks assessed as medium or above Operation and risks assessed medium or higher Landscape character and visual amenity Existing conditions Landscape character Impact assessment Change to landscape character Visibility of the transmission line Visual impact at private viewpoints Mitigation and management Landscape planting Tree planting Performance Requirements Geology, geomorphology and soils Existing conditions Geology Topography and geomorphology Soils Impact assessment Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Risks assessed as low Performance Requirements Surface water and groundwater Existing conditions Surface water Groundwater Impact assessment Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Table of Contents

5 6.4.2 Risks assessed as low Performance Requirements Flora and fauna Existing conditions Flora Fauna Key areas of ecological value Impact assessment Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Risks assessed as low Performance Requirements Cultural heritage Existing conditions Aboriginal cultural heritage Non-Aboriginal cultural heritage Impact assessment Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Risks assessed as low Performance Requirements Air quality Existing conditions Dust Meteorology Rain Wind Cloud Frost and fog Impact Assessment Table of Contents 3

6 9.3 Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Risks assessed as low Performance Requirements Noise and vibration Existing conditions Potentially sensitive receptors Noise monitoring Vibration monitoring Noise and vibration goals Impact Assessment Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Risks assessed as low Performance Requirements Transport infrastructure Existing conditions Arterial and local roads Casualty crash history Bicycle trails Impact assessment Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Risks assessed as low Performance Requirements Socio-economic effects Existing conditions Table of Contents

7 Social assets and land use Impact assessment Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Risks assessed as low Performance Requirements Infrastructure and services Existing conditions Electricity Water Wastewater Gas Stormwater Telecommunications Oil pipeline Railway Crossing constraints Impact assessment Construction Risks assessed as medium or above Risks assessed as low Operation Risks assessed as medium or above Risks assessed as low Electromagnetic fields Existing conditions Impact assessment Overhead transmission lines Underground transmission cables Terminal stations Prudent avoidance Summary of effects of the Power Supply Assessment methodology Table of Contents 5

8 15.2 Existing environment Construction of the Power Supply Operation of the Power Supply Conclusions Table of Contents

9 Figures Figure 1-1 Reference Project, Variation and Options for the Power Supply Figure 2-1 Existing electrical network Figure 2-2 Network supply options Figure 2-3 Schematic of northerly 220 kv overhead connection Figure 2-4 Transmission line alignment and investigation corridor Figure 2-5 Corridor and alignment for the northerly 220 kv overhead connection Figure 2-6 Typical 220kV transmission lines using steel lattice towers (left) and steel poles (right) Figure 2-7 Proposed location of the Tynong North Terminal Station Figure 2-8 Proposed location of the Woolamai Terminal Station Figure 2-9 Typical layout of underground cables in a trench Figure 2-10 Potential envelope for alternative northerly alignment Figure 2-11 Gas pipeline alignment Figure 4-1 Topography characteristics of areas of the grid connection Figure 4-2 Landscape units overlaid over the grid connection alignment Figure 4-3 View of the coastline adjacent to the proposed site Figure 4-4 Coastal dunes near the plant site Figure 4-5 Coastal plains Figure 4-6 Undulating cleared farmland Figure 4-7 The Powlett River as it crosses the coastal plain near the coast Figure 4-8 Riverine landscape character Figure 4-9 Looking north-west over Kilcunda Figure 4-10 Alluvial plain Figure 4-11 Typical work for bored pier foundations Figure 4-12 Typical works for pad and pier foundations Figure 4-13 Installation of underground cables Figure 4-14 Photomontage of the Tynong terminal station view north from the Princes Highway Figure 4-15 Example of transmission structures used for assessment Figure 4-16 Example of 220 kv steel poles Figure 4-17 Seen area analysis for the transmission line Figure 4-18 Publicly accessible viewpoints Figure 4-19 Residential properties assessed Figure 4-20 View to the north west towards the transmission line Figure 4-21 Existing distribution line within viewpoint C Figure 4-22 Stockyards in property at viewpoint D Figure 4-23 Oak Tree Figure 4-24 View looking north Figure 4-25 View across the valley from viewpoint F Figure 4-26 Photomontage of lattice towers at viewpoint G Table of Contents 7

10 Figure 4-27 Photomontage of steel poles at viewpoint G Figure 4-28 Photomontage of lattice tower at viewpoint H Figure 4-29 Photomontage of steel poles at viewpoint H Figure 4-30 Photomontage showing lattice towers at viewpoint I Figure 4-31 Photomontage showing steel pole at viewpoint I Figure 4-32 View from the northern side of existing residence at viewpoint J Figure 4-33 Photomontage showing lattice towers at viewpoint K Figure 4-34 Photomontage showing the steel pole transmission line at viewpoint K Figure 4-35 Photomontage showing lattice tower at viewpoint L Figure 4-36 Photomontage showing steel pole transmission line at viewpoint L Figure 4-37 Photomontage showing lattice towers at viewpoint M Figure 4-38 Photomontage showing steel pole at Viewpoint M Figure 4-39 View from 328 Ferriers Road Figure 4-40 View along the driveway of 55 Hornbuckle Road Figure 4-41 View from 125 Ferriers Road Figure 4-42 View from 35 Tynong North Road Figure 4-43 View looking west towards the transmission line Figure 4-44 Existing view from proposed house location Figure 4-45 View from rear of house at 574 Lang-Lang Poowong Road Figure 4-46 Existing view from rear of house at 240 Berry s Road Figure 4-47 View from rear of house at 501 Stewarts Road, Kernot Figure 4-48 Photomontage of lattice tower at viewpoint W Figure 4-49 Photomontage of steel poles at viewpoint W Figure 4-50 Existing view from rear of house at Goldies Road, Loch Figure 4-51 Existing view from rear of house at 3 Goldies Road, Loch Figure 4-52 Landscape mitigation planting Figure 4-53 Tree planting in front of the transmission line Figure 4-54 Tree planting behind the transmission line Figure 4-55 Foreground planting Figure 4-56 Planting of deciduous trees Figure 4-57 Recommended infrastructure selection Figure 4-58 Transmission line perpendicular to roads Figure 4-59 Transmission line parallel to roads Figure 5-1 Proposed Power Supply alignments Figure 5-2 Regional geology and structure (faults) of Western Port Basin and margins Figure 5-3 Tynong Granite at Tynong North showing existing powerlines Figure 5-4 Weathered Strzelecki Group sediments in cutting on Kilcunda Ridge Road Figure 5-5 Baxter Formation sands and sandy clays with a capping of Cranbourne Sand Figure 5-6 Main drain across former Koo Wee Swamp near Vervale Figure 5-7 3D view of West Gippsland showing proposed Power Supply transmission line alignment Table of Contents

11 Figure 5-8 Geomorphological units of the Western Port sunkland Figure 5-9 Area of potential acid sulfate soil at powerline crossing of Powlett River Figure 6-1 River health for major waterways crossed by the grid connection corridor Figure 9-1 Monthly rainfall statistics for the Wonthaggi area Figure 9-2 Wind roses from on-site monitoring at Wonthaggi Figure 9-3 Summer wind roses at weather stations local to the grid connection Figure 9-4 Pakenham annual wind rose Figure 9-5 Rhyll annual wind rose Figure 9-6 Kilcunda annual wind rose Figure 9-7 PM10 dust concentration from continuously operating construction site at Wonthaggi Figure 9-8 PM10 dust concentration from continuously operating construction site on the Kilcunda Ridge 9-13 Figure 9-9 PM10 dust concentration from continuously operating construction site north of Grantville (eastern edge of Western Port) Figure 9-10 PM10 dust concentration from continuously operating construction site at Pakenham Figure 10-1 Woolamai Terminal Station noise modelling results Figure 10-2 Tynong North Terminal Station noise modelling results Figure 11-1 Bass Highway north of Grantville, southbound view Figure 11-2 Bass Highway south of Grantville, southbound view Figure 11-3 South Gippsland Highway north of Bass Highway, southbound view Figure 11-4 South Gippsland Highway at the grid connection crossing, eastbound view Figure 11-5 Lang Lang Poowong Road at the grid connection crossing, westbound view Figure 11-6 Westernport Road near Wildes Road, westbound view Figure 11-7 Koo Wee Rup-Longwarry Road in the vicinity of the proposed grid connection crossing, eastbound view Figure 11-8 Nar Nar Goon-Longwarry Road, eastbound view Figure 11-9 Princes Freeway, west of Brew Road at the grid connection crossing, eastbound view Figure 12-1 Locality of the grid connection Figure 14-1 Comparison of typical magnetic field for 220 kv, 132 kv and 66 kv double circuit overhead lines Table of Contents 9

12 Tables Table 1-1 Reference Project, Variation and Options for the Power Supply Table 2-1 Estimated average electrical energy requirements Table 2-2 Summary of impacts for grid connection options considered Table 2-3 Key distinguishing factors for grid connection options Table 2-4 Criteria for location of terminal station Table 2-5 Tower and pole dimensions for 220 kv line Table 2-6 Pole dimensions for 66 kv and 22 kv lines Table 2-7 Key elements for gas supply Table 3-1 Risk assessment matrix Table 3-2 Summary of construction effects for the Power Supply assessed as medium and above Table 3-3 Summary of operational effects of the Power Supply assessed as medium and above Table 4-1 Landscape sensitivity Table 4-2 Transmission line viewshed extent and zones of visual influence Table 4-3 Visual impact on publicly accessible viewpoints Table 4-4 Infrastructure specification Table 4-5 Houses within 2 km and 700 m of the northerly gird corridor Table 4-6 Properties assessed Table 4-7 Performance Requirements Table 5-1 Geology and geomorphology along the transmission line Table 5-2 Construction risks assessed as medium or above Table 5-3 Performance Requirements Table 6-1 SEPP Water Quality Guidelines for Waters of Western Port and catchment Table 6-2 River catchments for the 66 kv underground cables and 220 kv transmission line Table 6-3 Estimation of aquifer confinement Table 6-4 Groundwater flow Table 6-5 Protected uses of the segments Table 6-6 Summary of groundwater salinity Table 6-7 Summary of bore use along the grid connection Table 6-8 Construction risks assessed as medium or above Table 6-9 Impacts associated with pipejacking and trenching Table 6-10 Reasons for waterways recommended for pipejacking Table 6-11 Performance Requirements Table 7-1 Ecological Vegetation Classes along the grid connection corridor Table 7-2 EPBC Act listed flora species Table 7-3 Significant fauna species Table 7-4 Construction risks assessed as medium or above Table 7-5 Performance Requirements Table 8-1 Previously recorded Aboriginal sites within the grid connection corridor Table of Contents

13 Table 8-2 Previously recorded Aboriginal sites within the grid connection corridor Table 8-3 Construction risks assessed as medium or above Table 8-4 Performance Requirements Table 9-1 Sources of dust surrounding the grid connection corridor Table 9-2 Daily PM10 concentrations in Victoria 75th percentiles during Table 9-3 Climatic information for the grid connection corridor Table 9-4 Annual rainfall and number of rain days at local weather stations Table 9-5 Construction risks assessed as medium or above Table 9-6 Relevant dust criteria to gauge off-site dust impact Table 9-7 Performance Requirements Table 10-1 Noise and vibration monitoring locations Table 10-2 Periodic average LA90 levels for day, evening, and night Table 10-3 Periodic minimum LA90 levels for day, evening, and night Table 10-4 Average peak particle velocities (mm/s) Table 10-5 Maximum peak particle velocities (mm/s) Table 10-6 Preliminary noise goals terminal stations and zoned substation Table 10-7 Accepted vibration dose values for intermittent vibration (m/s1.75) Table 10-8 Preferred and maximum weighted rms values for continuous vibration acceleration (m/s2) 1-80 hertz Table 10-9 Building damage vibration limits Table Construction risks assessed as medium or above Table Predicted plant item noise levels, db(a) Table Operational risks assessed as medium or above Table Estimated transformer sound power level Table Performance Requirements Table 11-1 Bass Highway north of Lower Powlett Road - Easter traffic volume summary Table 11-2 South Gippsland Highway traffic volume summary Table 11-3 Summary of sites in the Bass Coast Shire with three or more crashes ( ) Table 11-4 Summary of sites in the Cardinia Shire with three or more crashes ( ) Table 11-5 Summary of sites in the South Gippsland Shire with three or more crashes ( ) Table 11-6 Summary of sites in the South Baw Baw Shire with three or more crashes ( ) Table 11-7 Vehicles generated from grid connection construction activities Table 11-8 Performance Requirements Table 12-1 Agricultural characteristics of the grid connection corridor Table 12-2 Construction risks assessed as medium and above Table 12-3 Operation risks assessed as medium and above Table 12-4 Performance Requirements Table 13-1 Details of overhead power lines crossing the grid connection corridor Table 13-2 Details of water mains crossing or running parallel to the grid connection corridor Table 13-3 Intersection locations of the Transfer Pipeline and grid connection Table of Contents 11

14 Table 13-4 Details of wastewater sewers crossing or running parallel to the grid connection corridor Table 13-5 Details of gas mains crossing the grid connection corridor Table 13-6 Telecommunications intersections with the grid connection Table 13-7 Railway crossings for the grid connection Table of Contents

15 Victorian Desalination Project document structure Victorian Desalination Project document structure

16 Volume 1 Synthesis of environmental effects Volume 2 Environmental effects of Marine Structures Volume 3 Environmental effects of Desalination Plant Volume 4 Environmental effects of Transfer Pipeline Volume 5 Environmental effects of Power Supply Victorian Desalination Project Document Structure This Victorian Desalination Project Environment Effects Statement comprises a main report and accompanying Technical Appendices. The main report is divided into five volumes. Volume 1 defines the Project and summarises its environmental effects. Volumes 2 to 5 provide detail on the Project s four components: Marine Structures Desalination Plant Transfer Pipeline Power Supply. Volume 1 explains the requirement for the Environment Effects Statement, sets the policy context and describes the Project evolution. It sets out the evaluation framework adopted to assess: the environmental effects of the Project, integrated across all of the Project components, as required by the Environment Effects Act 1978 (Vic) the environmental effects of the project on matters of national environmental significance, as required by the Environment Protection and Biodiversity Conservation Act 1999 (Cwlth). Volume 1 also presents an overview of the environmental impact and risk assessment contained in Volumes 2 to 5 and the Technical Appendices together with an Environmental Management Framework to mitigate, manage and monitor the effects. Victorian Desalination Project Document Structure i

17 Volumes 2 to 5 describe the Project components and summarise the potential interactions between the component and the environment during construction and operations phases. Each volume then presents the environmental effects of the component. The assessment of these effects is based on specialist reports provided in the Technical Appendices. A Summary Brochure has been prepared to provide a concise and clear summary of the Victorian Desalination Project Environment Effects Statement, the environment of the region, the potential effects associated with the construction and operation of the Project, and mitigation measures to manage or avoid potentially significant effects. The Summary Brochure is based on information presented in this Environment Effects Statement. Volume 5 Environmental Effects of Power Supply This volume describes the Power Supply in detail and it describes the Reference Project and Variations and Options for assessment. It describes interactions of Project components with the terrestrial environment, including the identification of potential hazards and risks for key environmental assets. It describes existing conditions, provides impact assessment, and discusses mitigation and management strategies for physical material and environmental quality, cultural and scientific assets as well as infrastructure and services. The chapters in Volume 5 are shown for ease of reference in the following table. Chapter Title Content 1 Introduction Describes the rationale for the approach taken to provide Options for Power Supply 2 Power Supply Project Description 3 Interactions with the environment Discusses Reference Project and Options for assessment and details the Power Supply development and operation concept as well as Project Requirements Describes the general characteristics of the environment around the Power Supply ii Victorian Desalination Project Document Structure

18 Chapter Title Content 4-14 Summarises existing conditions, provides impact assessment, and discusses mitigation and management strategies based on specialist investigations. The environmental aspects assessed are: Ch 4 Landscape character and visual amenity Ch 5 Geology, geomorphology and soils Ch 6 Surface water and groundwater Ch 7 Flora and fauna Ch 8 Cultural heritage Ch 9 Air quality Ch 10 Noise and vibration Ch 11 Transport infrastructure Ch 12 Socio-economic effects Ch 13 Physical infrastructure Ch 14 Electromagnetic fields 15 Summary of environmental effects Summarises the environmental, social and energy effects of the construction and operation of the Power Supply Victorian Desalination Project Document Structure iii

19 1.0 Introduction 1.0 Introduction

20 Volume 1 Synthesis of environmental effects Volume 2 Environmental effects of Marine Structures Volume 3 Environmental effects of Desalination Plant Volume 4 Environmental effects of Transfer Pipeline Volume 5 Environmental effects of Power Supply Technical Appendix Chapter 1 Introduction 1 Introduction 1.1 Basis of the Project Description An overview of the Project, the project delivery process and the environmental impact and approvals process is provided in Volume 1 Chapter 1. That chapter explains that the Project will be delivered by a Project Company under contract to the State under a Public Private Partnership (PPP) structure. The ultimate Project design will be determined from among designs, bid competitively by commercial consortia, who will be seeking to provide value for money and design innovation to the Government for delivery of the Project. There are a number of forms in which the Project could be delivered by the Project Company to meet the broad objective of supplying desalinated water to Melbourne, and potentially to regional water authorities. Further detail of this process and its interaction with the EES is provided in Volume 1 Chapter 1. The final form of the Project will not be determined until after the completion of the EES. Accordingly, the EES needs to be flexible so that it does not unduly impede innovation and reduce the benefits of the PPP procurement. To meet this challenge, the EES is based on a Project Description that is more complex than is usual for an EES. This approach is explained more fully in Volume 1 Chapter 1 and is demonstrated in Volume 1 Chapter 4. Chapter 1 Introduction 1-1

21 The Project Description and subject matter of this EES is: the Performance Requirements the Reference Project Variations. The Performance Requirements govern the Project for EES purposes and are intended to be the basis for any contract with the Project Company. The Performance Requirements set the environmental parameters for the Project. The Reference Project is an integrated response to the Performance Requirements developed by the State. It is used in this EES to demonstrate the Project's feasibility and ability to achieve acceptable environmental outcomes. Variations contemplate other design and management solutions which also meet the Performance Requirements and are within the scope of this EES assessment. In addition, the EES identifies Options that may potentially be of interest to the Project but have not been considered further for technical or commercial reasons, or because they did not appear to offer significant advantages over the Reference Project. While these Options have not been fully assessed in the EES, they are matters upon which comment is invited. Any further process for the Options will be determined by the Minister for Planning prior to any endorsement by the State for utilisation in the Project. The EES submits for assessment a Reference Project (with Variations). However, no decision has been made by the State as to the final form of the Project. As a Partnerships Victoria Project it is expected that a range of energy solutions could be brought forward by proponents. For example, power supply could be provided by any one of the Power Supply Options outlined in this EES. The key infrastructure elements of the Reference Project, Variations and Options for the Power Supply are shown in Table 1-1 and Figure 1-1 and are discussed in Chapter 2 of this volume. 1-2 Chapter 1 Introduction

22 Table 1-1 Reference Project, Variation and Options for the Power Supply Key element s Reference Project Variation Options Alternative corridor/ alignment New segments of corridor/alignment Responding to landowner requirements and detailed design. Grid connection underground Power Supply Grid connection northerly Overhead 220 kv lines from Tynong North to a terminal station in the vicinity of Woolamai, then underground 66 kv lines to the Desalination Plant Provides for the Desalination Project and supports the local region. Alternative alignment within corridor Deviations of alignment within corridor responding to landowner requirements and detailed design. Acceptable provided major environmental assets are avoided. Tynong North to Woolamai Underground high voltage transmission line Gas-fired power station on plant site and gas supply lines A stand alone gas-fired power station on the plant site and supplied with treated gas. Gas supplied either along the BassGas or Alinta gas corridors Hybrid gas-fired power station and wind farm A combination of wind power in the region (Bald Hills), gas-fired power station and interconnecting powerlines Chapter 1 Introduction 1-3

23 Figure 1-1 Reference Project, Variation and Options for the Power Supply 1.2 Performance Requirements The Performance Requirements (PRs), in their final form are intended to specify the Government s requirements for Project performance and will form the basis of contractual obligations. In assessing the environmental effects of the Project, reliance should ultimately be placed on the PRs rather than the Reference Project. While a specific finding on the acceptability of the Reference Project and Variations is sought, the PRs are the Project outcomes which will apply regardless of the specific solutions adopted. 1-4 Chapter 1 Introduction

24 The PRs (as ultimately resolved from the outcomes of the environmental assessment processes) will be used: to assess the capacity of a bid project to perform in accordance with the PRs and the level of that performance to inform the contractual requirements for performance by the Project Company. The PRs are incorporated into the Environmental Management Framework and embody the recommendations of environmental management arising from the environmental impact and risk assessment process. The relevant PRs for each impact assessment are presented at the end of each chapter in this EES Volume, along with commentary about linkages to the relevant management measures suggested in the technical investigations in relation to the Project. Chapter 1 Introduction 1-5

25 2.0 Power supply project description 2.0 Power supply project description

26 Volume 1 Synthesis of environmental effects Volume 2 Environmental effects of Marine Structures Volume 3 Environmental effects of Desalination Plant Volume 4 Environmental effects of Transfer Pipeline Volume 5 Environmental effects of Power Supply Technical Appendix Chapter 2 Power Supply components 2 Power Supply components 2.1 Purpose of the new Power Supply infrastructure The electrical energy required to operate the Desalination Plant and associated infrastructure will exceed the capacity of existing electricity infrastructure in the Wonthaggi area. Therefore, new infrastructure for the supply of energy to the Plant whether from a direct source or from the Victorian electricity grid is required for the project and included within the scope of this EES. Because electricity generation and supply is the responsibility of licensed generators, retailers and distributors operating within a National Electricity Market, this aspect of the Project is dependent on third parties, and is to some extent constrained by the regulatory and market priorities of those parties. In addition, the economics of the electricity industry encourage generator connection to the integrated electricity supply grid rather than stand-alone infrastructure Power requirements The estimated electrical energy requirements of the Desalination Plant and related infrastructure based on the Reference Project are set out in Table 2-1. Chapter 2 Power Supply components 2-1

27 Table 2-1 Estimated average electrical energy requirements Component requiring energy Initial 150 GL/y Plant with transfer pump station Ultimate 200 GL/y Plant with transfer pump station Pipeline booster pump station (150 GL/y Plant) Pipeline booster pump station (200 GL/y Plant) Tunnel boring machine/other power uses for construction Average electrical requirements 82 MW 115 MW 10 MW 18 MW 10 MW Current regional supply The general arrangement of the existing electrical network in eastern Victoria is shown in Figure 2-1. The network comprises transmission and distribution networks. 2-2 Chapter 2 Power Supply components

28 Figure 2-1 Existing electrical network Chapter 2 Power Supply components 2-3

29 SP AusNet through its subsidiary SPI Electricity, operates and manages the distribution network serving eastern Victoria, including South Gippsland. The distribution network consists of mainly overhead lines comprising a subtransmission network that operates at 66 kv and a lower voltage distribution network which generally operates at 22 kv. The South Gippsland 66 kv network originates from Morwell Terminal Station and supplies four 66/22 kv zone substations at Foster, Leongatha, Wonthaggi, and Phillip Island. Two wind farms are connected to the network at Toora and Wonthaggi. The South Gippsland 66 kv network currently has practically no spare capacity to connect new load. The network is also very heavily loaded during the peak demand time at the hot water peak (00:00-03:00 hours every night) and in the evenings during holiday periods. As the result of heavy loading, there have been several occurrences in the past four years where conditions on the network have resulted in blackouts, or have required load shedding to avoid blackouts, or where network stress has only been avoided by fortuitous wind farm generated supply. These events have occurred even with all 66 kv lines in service. SP AusNet s plans include augmentations for zone substations and 66 kv lines over the next five years to enhance the supply capacity of the South Gippsland 66 kv network. Further augmentations will be required over the ensuing decades to meet the long term load growth and improve reliability for the region. The distribution network supplying the South Gippsland region will not have the capacity, even with the planned augmentations, to supply power to a 150 GL to 200 GL per year Desalination Plant. The Extra High Voltage (EHV) transmission network (220 kv and above) in Victoria, owned and operated by SP PowerNet (subsidiary SPAusNet), has the capacity to supply the power requirement of a 150 to 200 GL Desalination Plant but is located approximately 70 kilometres away from the Desalination Plant. 2-4 Chapter 2 Power Supply components

30 Renewable energy In the current policy climate of greenhouse gas awareness, there is a strong preference for the Desalination Plant and associated infrastructure to be directly powered by renewable energy. Considerable effort has been invested in identifying renewable energy sources for use in the Project. These investigations, and their outcomes, are documented in a later part of this chapter. A constraint from the point of view of the Desalination Plant is the unreliability of wind and solar energy in the context of the almost continuous power demand from the Desalination Plant. This means that at times of little or no wind or solar isolation, the electrical demand for the operation of the Desalination Plant could not be reliably supplied. Use of wind power (as the most likely local renewable source) or alternative renewable energy sources would need to be combined with gas-fired electricity generation or grid connection to provide supply when the renewable energy source was off-stream. Unless a local sub-station is able to divert locally generated renewable electricity to local consumers, the nature of the integrated energy supply market makes it impossible for a consumer to distinguish between different energy sources contributing to the grid. Green power cannot be purchased directly but is purchased indirectly through a commitment by the supplier to source an equivalent amount of energy from a renewable source. If therefore, the Desalination Plant were connected to the grid, the means by which it would use a renewable energy supply would be by offsetting its consumption with renewable energy certificates. Responding to these considerations, the State will require that 100 per cent of the electricity used in operating both the Plant and the Transfer Pipeline be offset by the purchase of Renewable Energy Credits (RECs) in respect of generation sources commissioned after 1 January These requirements are in addition to the State s current renewable energy targets and credits must be purchased from generators registered with the Victorian Renewable Energy Target (VRET), generators registered with the Commonwealth s Mandatory Renewable Energy Target (MRET) scheme or electricity generation sources located in Australia and which satisfy the verification and audit requirements imposed on the Project Company under the Project Deed. Chapter 2 Power Supply components 2-5

31 This is a significant commitment being made by the Victorian Government for a project of this scale. The objective of the Victorian Renewable Energy Target (VRET) scheme is to increase the consumption of electricity generated from renewable sources in Victoria to ten per cent by 2016 (3274 GWh). There are currently approximately MW of wind farms planned for Victoria alone ( which would be expected to generate about GWh per year. These include wind farms that are approved but not operational or those that have lodged permit applications. The renewable energy offset requirements for the Desalination Plant are about MWh (RECs), which is about 8 per cent of the generation from the planned Victorian wind farms. The percentage from a national perspective would obviously be much lower. Further information on the implications of the Desalination Project in terms of greenhouse gas emissions and the Performance Requirements for renewable energy offsets is included in Chapter 6 of Volume 1 of this EES. 2.2 Evolution of the Reference Project Accepting that the Project s renewable energy target will almost certainly be met through offsets (in the form of Renewable Energy Certificates) rather than direct supply from a renewable energy source, a range of solutions for obtaining the electrical energy needed for the Desalination Plant and associated infrastructure were investigated. Along with the evaluation objectives set out in Chapter 5 of Volume 1 of this EES, the following key considerations were taken into account when identifying and evaluating the power supply solutions: ensuring a sufficient and reliable ongoing supply of power for the continuous operation of the Desalination Project selecting the best value technology for the Power Supply from the range of potentially feasible options minimising impacts on the environment through measures such as energy efficiency, route selection to minimise adverse impacts and design of Power Supply infrastructure to mitigate impacts on local amenity and other measures appropriate to specific solutions. 2-6 Chapter 2 Power Supply components

32 This led to the identification of three general solutions: grid connected, gas-fired and hybrid options. The grid connection is explained in more detail below. The gas-fired and hybrid options are explained in section Connection to the grid Connections to the transmission network are governed by a number of legislative/regulatory instruments the National Electricity Law (NE Law), the National Electricity Rules (NE Rules), the Victorian Electricity Industry Act, Transmission Licences and the Victorian System Code. Transmission network asset owners (SPI PowerNet) and network service providers (VENCorp) have obligations under those instruments in relation to connections to the transmission network. Victorian Energy Network Corporation (VENCorp) is the Victorian Network Service Provider with statutory responsibility for planning, expanding and approving connections to the Victorian shared extra-high voltage (EHV) transmission network, and directing expansion of the network. VENCorp procures shared EHV network services from asset owners, primarily SPI PowerNet. SPI PowerNet, a subsidiary of SP AusNet, is responsible for owning, maintaining and operating its EHV transmission network to provide services as defined in its Network Agreements with VENCorp and Connection Agreements with other transmission customers. In fulfilling its role to plan and direct the augmentation of the shared transmission network, VENCorp is required to provide a level of transmission system capability consistent with those instruments. SPI Electricity plans its distribution network in a manner consistent with the planning for the upstream network and connection points. The objective is to develop transmission and distribution facilities in an economically efficient manner. There are two connection approaches that could be followed for seeking connection of the Desalination Plant to the grid: Chapter 2 Power Supply components 2-7

33 a transmission connection application could be made to VENCorp (and SPI PowerNet) for a direct connection to the shared EHV network. VENCorp would assess the technical need for development of the shared EHV network a distribution connection application could be made to SPI Electricity for connection to its 66 kv network who would assess the need for augmentation of its sub-transmission network and would liaise with VENCorp in relation to the need for augmenting the shared EHV network in order to support the new load. Transmission connection application VENCorp, SPI PowerNet and SPI Electricity are required to consider the Desalination Plant s connection requirements in the context of how that connection could provide opportunities for the future development of the network. In other words, facilitate a Shared Solution for other electricity users in the region. This Shared Solution would also reduce the need for further works at Morwell Terminal Station, which currently is very congested, to support reliability and capacity improvements to the South Gippsland region. However, the State could pursue a dedicated transmission connection to service the Project if a Shared Solution proved unattractive. The Shared Solution would augment supplies to the local region. Distribution connection application Following the distribution connection approach should result in the same outcome but would be facilitated through SPI Electricity. In the event that their sub transmission network does not have the capability (as is the case), SPI Electricity would pursue a connection application with VEN Corp. 2-8 Chapter 2 Power Supply components

34 2.2.2 Transmission Connection Approach The State examined a range of options, including 66 kv, 132 kv and 220 kv options for a transmission connection on a Shared Solution basis. The 66 kv option did not provide a technically feasible solution. The 132 kv option would require specific spares (132 kv transformation and switchgear) and maintenance gear because 132 kv equipment is not currently used in Victoria and as such would not be supported by VENCorp or SP AusNet. As a result, the northerly double circuit 220 kv overhead transmission line was identified as being the lowest cost shared grid connection solution (refer section below). A Shared Solution would be treated by VENCorp as a proponent funded augmentation by the Desalination Plant. The costs of the augmentation would be borne by the Desalination Project and SP AusNet. The Shared Solution provides SPI Electricity with an opportunity to reassess its existing plans for development of the South Gippsland distribution system. This reassessment has identified the opportunity to achieve significant long-term cost savings for SP AusNet s distribution customers if the proposed 220 kv augmentation is commissioned. Therefore, in accordance with provisions contained in VENCorp s Connection Augmentation Guidelines, SP AusNet intends to make a financial contribution for the benefit of its customers by connecting to the proposed Shared Solution, on the basis that it would provide the most costeffective option for meeting the forecast requirements of distribution network users in the South Gippsland area (over a thirty year planning horizon). The amount of the financial contribution made by SP AusNet would be recovered from distribution network users through network tariffs within the regulated process (ESC and/or AER) for approving tarrifs. Given that the existing electricity supply to the South Gippsland region is overstretched and a capacity upgrade will be required in due course, the establishment of a Shared Solution would have a benefit to the region. Chapter 2 Power Supply components 2-9

35 2.2.3 Assessment of grid connections Hydro Tasmania Consulting (HTC) (refer to Technical Appendix 81) was engaged to assess alternatives to provide a secure electricity network connection for the proposed Desalination Plant near Wonthaggi. The following means of connecting to the existing grid were considered: northerly 220 kv overhead northerly 220 kv underground northerly high voltage direct current (HVDC) underground northerly 132 kv overhead western 220 kv overhead northerly 66 kv overhead eastern 66 kv from Latrobe Valley western sub-sea eastern HVDC sub-sea. These alternative grid connections are shown schematically in Figure 2-2 and discussed briefly below Chapter 2 Power Supply components

36 Figure 2-2 Network supply options Chapter 2 Power Supply components 2-11

37 Northerly 220 kv overhead This proposal comprises: A new terminal station near Tynong North to connect to the existing 220 kv lines that run from Hazelwood to Rowville A new double circuit 220 kv overhead line on lattice towers running from Tynong North to Woolamai A new terminal station near Woolamai to transform voltage from 220 kv to 66 kv for supply to the local region and the Desalination Plant three 66 kv underground circuits from Woolamai to the Desalination Plant (other 66 kv feeders from Woolamai terminal station would augment supply to the local region). The double circuit 220 kv option was assessed as a technically feasible way of providing approximately 270 MW of power to the Desalination Plant and Wonthaggi region even under conditions where one of the circuits was out of service (N-1). It would easily cover the anticipated load growth of the Wonthaggi and Phillip Island area for more than 30 years. Due to the fact that one circuit would be sufficient to meet the local power demand, the availability of the power to the Desalination Plant would be very high. High voltage circuits with the fewest ancillary components (transformers and reactors) are the most efficient method of power transmission. The 220 kv double circuit met these criteria with incremental power losses of about 5.4 MW. This was also considered to be one of the few options that could be completed in time for pre-commissioning of the plant and subsequent operation by The capital cost of this proposal was estimated at approximately $220 million. Northerly 220 kv underground This was similar to the northerly 220 kv overhead proposal except that the 220 kv transmission line was replaced by two 220 kv underground circuits (6 cables). High voltage underground cables were assessed as technically feasible for this transmission distance Chapter 2 Power Supply components

38 However, the capital cost of this proposal was estimated to be more than double the cost of the northerly 220 kv overhead proposal. Further, the cost of providing underground cables is highly dependant on the base metal prices at the time of purchase, the cables are likely to be copper. The price for copper is presently around $8000/tonne (which reflects a three-fold increase in the past three years), and the price is not expected to fall given the anticipated levels of demand. This being the case there is a risk that the cost could be considerably more than that estimated. Underground AC cables can be very efficient when sufficient conductor crosssectional area is specified. For two 220 kv circuits with 800 mm 2 conductors the incremental power losses were estimated at be about one megawatt. The most critical timing issue with larger underground cable systems is the lead time for the supply of the cable and accessories. Preliminary advice suggested that lead time for full cable delivery could exceed 18 months, which means that this proposal would have considerable time constraints compared to the overhead transmission line proposals. Northerly HVDC underground This option is similar to the northerly 220 kv underground proposed except that the 220 KV cables are replaced with an underground HVDC solution (incorporating a converter station at each end). The DC technology considered for this option is similar to the type used for the Murraylink project. The connections to the 220 kv Hazelwood/Rowville lines would be the same as for the northerly 220 kv options except for the inclusion of an AC/DC converter station at the Tynong North Terminal Station. An underground HVDC link (3 cables to achieve supply redundancy) would then be constructed (approximately 60 kilometres) to the Woolamai Terminal Station. A converter station would be included in the Woolamai Terminal Station to convert DC to 66 kv AC. From there the 66 kv circuits would connect to the Desalination Plant as per the 220 kv option. Chapter 2 Power Supply components 2-13

39 The HVDC solution using voltage sourced converter (as for Murraylink) is technically achievable and is ideally suited for the provision of power from strong to weak AC systems. This HVDC solution is considered superior to the technology employed for Basslink for this application (refer eastern sub-sea connection option below). Extensive power system studies could be required to fully scope this solution. Whilst the AC transformers and cables are likely to be delivered in the timeframe of the project, the lead time on converter station equipment can be significant. Preliminary advice from manufactures indicates that the cost of this option would be about three to four times that estimated for the northerly 220 kv overhead option and about 40 to 60 per cent higher than the northerly 220 kv underground connection. Northerly 132 kv overhead This connection would comprise: a new terminal station near Tynong North to connect to the existing 220 kv lines that run from Hazelwood to Rowville. Transformers would be required to transform the voltage from 220 kv to 132 kv two double circuit 132 kv overhead lines on lattice towers running from Tynong North to Woolamai a new terminal station near Woolamai to transform voltage from 132 kv to 66 kv for supply to the local region one double circuit 132 kv line from the Woolamai terminal station to the desalination plant. The four circuit 132 kv option was assessed as a technically feasible way of providing up to 360 MW of power to the Wonthaggi region even under conditions where one of the circuits was out of service (N-1). It would cover the projected load growth of the Wonthaggi and Phillip Island area for the next 30 years (expected to be maximum 270 MW). The availability of the power to the Desalination Plant was also very high Chapter 2 Power Supply components