Life Cycle Assessment of offshore and onshore sited wind farms.

Transcription

1 Note 20 October 2004 Elsam Engineering A/S Our ref. HHA/AAH/AWK Project no. T Page 1 of 54 Verified: AWK Approved: HHA Life Cycle Assessment of offshore and onshore sited wind farms. This report is a translation made by Vestas Wind Systems A/S of the Danish Elsam Engineering report of March 2004 written in Danish. In matters of doubt the Danish version applies

2 Page 2 of 54 Contents: 1. Introduction Goal Objective Target group Method Scope Functional unit Lifetime Life cycle stages Offshore wind farm Electric power generation Operation LCA model Onshore wind farm Electric power generation Operation LCA model Data collection Procedures for data collection Workshop about reuse Allocations Manufacturing of turbines Manufacturing of onshore foundation Manufacturing of offshore foundation Manufacturing of internal farm cables to offshore wind farm Manufacturing of transformer station to offshore wind farm Manufacturing of 150 kv PEX submarine-/onshore cable and SF6-system for offshore wind farm Incoming materials Life cycle impact assessment Environmental impacts Calculation method Results Statement of resource consumption Environmental impacts of 1 kwh Environmental impacts divided on life stages Environmental impacts divided on components Comparison with Danish electricity Interpretation of results Improvement strategies Energy balance Energy consumption Energy balance Environmental Product Declaration Environmental Product Declaration Methodological requirements in the Nordic region.42

3 Page 3 of Data quality for V80-offshore wind farm Environmental Product Declaration Environmental impact categories used in this Environmental Product Declaration LCA-method and system delimitation Sensitivity assessment Energy production Energy consumption Location Lifetime Recycling Shortcomings Conclusions...53 Appendix Appendix 1. Main components Appendix 2. Danish Environmental Declaration of Contents Appendix 3. Energy balance

4 Page 4 of 54 Summary This report makes up the final reporting for the project Life cycle assessment (LCA) of turbines Analysis of possibilities of product directed environmental optimisation effected by Elsam Engineering A/S and Vestas Wind Systems A/S financed by Elsam Engineering s work through the Danish Energy Authority s energy research programme for year 2000 (ERP2000). Vestas Wind Systems A/S financed its own participation in the project. The purpose of the project is to carry through a life cycle assessment of an offshore wind farm and an onshore wind farm, respectively, as a basis for assessment of environmental improvement possibilities for wind farms through their life cycles. Likewise, the results are used to elaborate an environmental declaration of contents for power delivered to the grid from both types of wind farms. The project has been running concurrently with a project about environmental assessment of future turbines, which RISØ is carrying out. Due to similarities between the two projects and the fact that RISØ s project supplements the LCA-project in more ways, cooperation about the projects has been going on through the process, in the form of exchange of experiences and results. In cooperation with RISØ, Elsam Engineering and Vestas Wind Systems A/S have carried through a workshop about dismantling and removal of wind farms. In that connection, we would like to address our gratitude to RISØ for their help in planning and carrying out the workshop. The project states the environmental impact for electricity produced at Horns Reef offshore wind farm and Tjæreborg onshore wind farm, respectively, as representatives for contemporary Danish offshore wind farms and onshore wind farms, respectively. Tjæreborg onshore wind farm is placed at an utmost favourably location with regard to wind, which means that the production at this wind farm is high compared with other onshore wind farms in Denmark. The high production rate is a factor that is taken into account when assessing the impact on the environment emanating from this wind farm. The results of the environmental life cycle assessments that have been carried out for the two wind farms do not show significant variance. If it is taken into account that Tjæreborg onshore wind farm is placed utmost favourably, the comparison shows that power from an average located onshore wind farm would have a more adverse or corresponding environmental impact as an unfavourably located offshore wind farm. The results show that it is the turbines that causes the largest environmental impact and not to a very high extent the transmission grid. For the turbines, the all-important environmental contribution comes from manufacturing and removal of the turbines, as it is the materials that cause the large environmental strain. The operation of the wind farms gives practically no contribution to the total environmental impacts. The foundations of the offshore wind farms make up a considerable factor to the total environmental impacts, as steel is a large constituent part of the foundations, some of which is abandoned at the seabed after dismantling of the farm. Therefore, the foundation of the offshore wind farms is selected as a focus area in connection with possibilities of product optimisation. Other types of foundations are assessed, and it is found that all the assessed foundation types give the same environmental impact, even though one of the types (caisson) will be completely removed from the seabed whereas in the case of other types (mono pile and tripod) everything more than 1 metre below the seabed is abandoned.

5 Page 5 of 54 Even though the operation does not contribute considerably to the environmental impacts, the environmental differences in using helicopter contra boat at maintenance of the offshore turbines have been examined. The differences are significant, as servicing by boat is insignificantly small. But irrespective of the way of transport the servicing will not contribute largely to the total impact from the entire farm in the total lifetime. 1. Introduction This report makes up the reporting in connection with the project LCA of turbines Analysis of possibilities of product directed environmental optimisation. The project is carried out in cooperation between Vestas Wind Systems A/S (hereafter called VWS A/S) and Elsam Engineering A/S. VWS A/S has financed its own part of the project, while the Danish Energy Authority s energy research programme (ERP) has paid Elsam Engineering s part. In the year 2001 VWS A/S and Elsam Engineering A/S completed a design scheme, in which a life cycle assessment was elaborated of a Vestas V MW turbine, which is used as basis for this life cycle assessment. Life cycle assessment (LCA) is a method to assess the environmental aspects and potential impacts of a product. LCA is a tool that is used to give a technical estimate of the environmental consequences of products and activities. The LCA does not include the financial and social factors, which means that the results of an LCA can not exclusively form the basis for assessment of a product s sustainability. It also means that an LCA does not give detached, scientific and final answers as to the environmental properties of a product, as an LCA does not include all the impacts on the surroundings caused by a product in connection with use (e.g. noise, use of area, impact on animal life, etc.) To obtain a more complete environmental description, LCA must be combined with other environmental assessments as for instance environmental consequence assessments (e.g. Assessment of Impact of the Environment, AIE), risk assessment and environmental management. LCA is a good tool to provide an understanding of environmental properties of a product and in many cases it can be used internally in companies as a part of the product development. Some of the most essential limitations of LCA are: Many selections and assumptions are to be made (e.g. selection of system boundaries and data sources), which might be subjective. The accuracy of an LCA will depend on the access to or the existence of relevant and liable data. Models used for mapping or assessing the environmental impact are restrained by their conditions and will not necessarily be accessible for all potential impact categories or applications.

6 Page 6 of Goal The purpose of the project has partly been to use life cycle assessments to environmental improvement strategies in connection with product development and partly to use LCA-data for preparation of an environmental declaration of contents for electricity produced on turbines. At the same time, the purpose of the project has been to work for a wide understanding of environmental declaration of contents and to influence the turbine trade ensuring concepts for a trade standard for environmental declaration of contents of turbines/electricity produced on turbines. 1.2 Objective The objective of the project can be divided in three sub-objectives: 1. Preparation of an LCA for an offshore sited and an onshore sited Vestas turbine, respectively, including grid connection. 2. Consideration of improvement strategies for every one of the life stages: Manufacturing, use and removal. 3. Preparation of an environmental product declaration (EPD) of the two turbine types and of electricity produced through these. 1.3 Target group This life cycle assessment is directed primarily to two target groups. : The Danish turbine industry, including employees in VWS A/S departments of environment and improvement of an integration of environment in the product improvement. The interested public including the Danish Energy Authority shall be able to use the overall results as part of an assessment of the turbine s environmental characteristics. 1.4 Method This LCA is carried out and reported according to the principles of ISO ISO deals with principles and framework and determines the overall frames, principles and requirements to establishment and reporting of LCA s. ISO goal and scope definition and inventory analysis together with ISO determine the requirements and procedures necessary for the data collection and improvements of objectives and delimitation of an LCA and also the establishment, interpretation and reporting of the mapping of a lifecycle. ISO life cycle impact assessment specifies requirements for the execution of the assessment of environmental impacts in the life cycle and relation between this and the other steps in the LCA. ISO life cycle interpretation determines requirements to and recommendation of the interpretation of results of a life cycle assessment or life cycle mapping. For modelling, the Danish Environmental Authority s pc-tool is used, based on the UMIP-method. UMIP is an abbreviation for environmental design of industrial products. (UMIP) is selected because Elsam Engineering has created an extensive database with materials, environmental impacts etc. and is already experienced when it comes to using the tool.

7 Page 7 of Scope The selected turbine type is a Vestas V80 2 MW turbine, as in the scheme design. In this project, however, both an onshore and an offshore sited wind farm are dealt with. The V80 turbine will be a little unlike for the 2 locations. The most essential difference is the tower height, but to this comes some smaller differences in the nacelle. The foundations are not produced by VWS A/S, but as for the two turbine locations the foundations differ considerably from each other, see more detailed descriptions in chapters 3 and 4. Main data for a V80 turbine is to be seen from Table 2.1. Table 2.1: Offshore turbine Onshore turbine Tower 140 t (60 m high) 165 t (78 m high) Nacelle 64 t 61 t Rotor 38 t 37 t Foundation 203 t 832 t Main data for turbines for offshore and onshore sited farm, respectively. 2.1 Functional unit The functional unit is selected as1 kwh electricity produced on the selected turbines. Therefore all the impacts are estimated for this functional unit, which makes the results comparable with the results from the LCA for other electricity production technologies. 2.2 Lifetime The lifetime of turbines and internal cables is 20 years, while for transmission cables, transformer stations and cable transition station the lifetime is 40 years. Still it is expected that the operation of the turbines as a principle will continue more than 20 years, but there is no certainty for this. When Elsam calculates financial circumstances of wind farms, it is based on the expected lifetime of 20 years. When the transmission grid is set to have an expected lifetime of 40 years it is based on the assumption that after 20 years lifetime of the farm, another farm will be erected or the existing will continue the operation for another 20 years. 2.3 Life cycle stages The life cycle of includes production, transport, erection, operation, dismantling and also removal of turbines, foundations and transmission grid. This is illustrated by the following figure with the attendant explanation of the specific life stages. Production of turbine farm components Transport to site and erection Operation. including maintenance Dismantling and scrapping Figure 2.1: Stages in the life cycle. Manufacturing: Manufacturing includes the manufacturing of foundation, tower, nacelle and blades for offshore and onshore turbines and also the manufacturing of parts of the transmission grid. Transport and erection: Transport from factory to erection site. This includes transport by truck (+ escorting car(s), in case where these are used) and transport by vessel at

8 Page 8 of 54 sea. Furthermore, transport of certain large components from subcontractors to VWS A/S is included in the model. Erection includes crane work and other construction work at site. Operation and maintenance: Change of oil, lubrication and transport to and from the turbines are included in the stage of operation and maintenance. Furthermore, renovation of gear and generator are included. The transport onshore is by truck, while at sea both vessels and helicopters are used. Dismantling and scrapping: This includes cranage for dismantling, transport from erection place to the final disposal (by vessel at sea and onshore by truck + escorting car(s), where necessary). Furthermore, the further handling of the materials is included, either by recycling or by deposit. The modelling is limited to the point where the material is ready for reuse. This means for instance that shredding and a certain loss to waste are included, while the manufacturing in itself is left out. A more detailed description of the wind farms and the included materials are presented in the following chapters.

9 Page 9 of Offshore wind farm The offshore wind farm in this LCA-study is exemplified by the planned offshore wind farm at Horns Reef, established by Elsam in The reason for this choice is firstly that the farm will be regarded as representative for offshore wind farms to be established these years. Secondly, the farm is owned by Elsam and is planned by Elsam Engineering, thus, access to farm data is relatively easy to achieve. The Horns Reef wind farm is placed in the North Sea approx 14 km from the coast of Blåvands Huk. The cable is to be connected ashore at Hvidbjerg Strand (seashore). For sketch of the farm complete with onshore connection cable, see Figure 3.1. Figure 3.1: Sketch of Horns Reef wind farm including connection cable to Hvidbjerg Strand. The farm consists of 80 Vestas V80 2 MW turbines erected in lattice pattern with a mutual distance of approx 560 metres. The depth of the water in the area is between 6.5 and 13.5 metres at mean sea level. The turbines are erected on mono pile foundations. A sketch of the foundation types are seen from figure 3.2. When designing the farm, it was assessed which of the three Wind foundation types mono pile, caisson or tripod, would be the best at Horns Reef. The mono pile is the cheapest of the three foundations, and due to the conditions at Horns Reef, e.g. a uniform sand bottom, it is possible to ram down the mono piles into the seabed. Besides, all other technical criteria can be fulfilled with mono pile foundation. Therefore, the mono pile is the preferred foundation for Horns Reef.

10 Page 10 of 54 Figure 3.2: Optional foundations for the turbines at Horns Reef. Mono pile is selected. The foundations have a diameter of approx 4 metres and are rammed down approx 25 metres into the seabed. Between foundation and tower there is a transition piece for counterbalancing the diameter. On every transition piece, a boat platform is mounted,. This platform is used when the turbines are visited by boat. The turbines are mutually connected by a 32 kv cable grid, which is assembled on the transformer station. At the transformer station, the produced energy from the wind farm is gathered and carried on to the shore. The transformer station is placed north-east of the offshore wind farm and consists of transformer, foundation, platform and internal cable. The foundation of the transformer platform, which has a lifetime of 40 years, consists of three piles; two of these have a diameter of about 1.6m and one has a diameter of 2.3m. The three foundation piles are mutually combined by lattice girders. 3.1 Electric power generation The electric power generation from Horns Reef wind farm is stated to 647 GWh/year 1, i.e. that each turbine produces MWh/year, corresponding to full loaded hours/year. These figures originate from recognized calculations of electric power generation and express a conservative assessment. This figure indicates the turbines production of electricity to be delivered to the transformer stations including the grid loss that might be in the internal cables on the farm. From the transformer station to connection to the existing transformer onshore, however, there is a grid loss in the transformer and the cables stated to 10 GWh/year for the total farm. Approx 10% of this loss goes from the transformer 2.

11 Page 11 of 54 Net loss:10gwh Horns Reef Wind Farm Horns Reef Wind Farm annual production 647 GWh 647GW 32/150 kv transformer station & 150kV cable 637GWh 637GW Connection to transmission line 637 GWh Figure 3.3: Creation of system for LCA-model of Horns Reef. 3.2 Operation In connection with operation of the turbines, wear and tear will take place especially of the rotating parts. The turbines are dimensioned and constructed to a lifetime of minimum 20 years. To be on the safe side in this environmental assessment, a conservative estimate situation of maintenance of the turbines is assumed. It is expected that during the lifetime of 20 years one reconditioning/renewal of half of the gears and the generators is to be undertaken, which, as a minimum, is expected to comprise a renewal of the bearings. To simplify the model of operation, only the gearboxes have been included, but in return the model comprises a total renewal of half of the gearboxes once in the turbine s lifetime. Thus, the model should now include an abundant amount of materials, as several of the gears and the generators will probably be repaired and not renewed. Moreover, the gearbox is significantly heavier than the generator. In addition, materials for servicing of the turbines are included in the form of change of oil and lubrication of gear, generator etc. The foundations of the offshore turbines are given cathodic protection as rust prevention, i.e. an active anode is used, which in this case is aluminium. This protection implies that aluminium is consumed through the lifetime. This is included in the operational stage. Paint repair and renewal of active anodes to the cathode protection must be carried out at the transformer station after an operation time of years. Further use of resources or materials is not included. It is estimated that inspection will be carried out 12 times a year. 9 of these are expected to be carried out by helicopter and the remaining 3 by boat. Inspection will also include about km a year by car. Regular inspection of the cables at the offshore farm is not included. However, the turbines are expected to receive servicing 5 times a year, which in 4 cases will be by helicopter and one time by boat. 11

12 Page 12 of LCA model The model includes the turbines, the internal cables, transformer station offshore, sea cable, cable transmission station onshore and onshore cable to the existing grid. Each of these includes materials, manufacturing, transport, erection, operation, dismantling and scrapping. Figure 3.4 shows the elements included in the LCA model for Horns Reef wind farm. Horns Rev Wind farm Cable transmission station 150 kv transformer Not included in LCA) 32 kv sea cable 32 kv seacable SF6 site 150 kv seacable 150 kv seacable System limit Figure 3.4: Sketch of structure of Horns Reef offshore wind farm with statement of system boundaries for the LCA.

13 Page 13 of Onshore wind farm The planned Tjæreborg wind farm is selected as an example of an onshore wind farm. The turbine type is a V MW turbine, but in this case the turbine type is for onshore placement. Figure 4.1: Placement and organisation of Tjæreborg wind farm. The existing turbines are marked with black, and the new turbines with red. In 2002, an onshore wind farm consisting of 8 turbines of various types with an effect of between 1.0 and 2.5 MW was established in Tjæreborg. One of these is a Vestas V MW turbine. A farm of this size is considered as a realistic size of an onshore wind farm with 2 MW turbines in Denmark. Therefore, the onshore wind farm is modelled as a farm with 8 Vestas V MW turbines. All the turbines are connected to the existing distribution grid in a 10/60 kv transformer station. The cables combining the turbines internally and to the transformer station are 10 kv cables. All cable extensions will take place in the soil. A new 10kV cable for the 4 new turbines will be established, as the existing electricity grid between the turbines in Tjæreborg can not lead to an additional effect of 8-10 MW. See Figure 4.3, for a principle sketch of Tjæreborg onshore wind farm. In Tjæreborg, there will be a total of 8 km of 10 kv cable for connection of all 8 turbines to the existing transformer station. The turbines are to be erected on concrete foundations. Each turbine foundation is established in connection to a road, working and turning area. The size of the foundations is dependent on the geotechnical conditions. Normally, the traditional bottom plates are approx 15 15m wide and 2m deep. In total, approx 400m 3 of reinforced concrete.

14 Page 14 of 54 The below figure shows a principle design of a bottom plate Figure 4.2: Principle sketch of bottom plate for onshore turbines. An access road is made with surface structure of gravel or any other approved road-making material. 4.1 Electric power generation A production calculation for the 4 new turbines in Tjæreborg is carried through, on condition that it is Vestas V MW onshore turbines. If the result of the production calculation aggregated with production data for the existing 2 MW turbine in Tjæreborg is used, it is found that the production from each Vestas V80 2 MW turbine is 5,634 GWh/year, corresponding to 2,817 full load hours. This is a quite high performance for an area onshore and corresponds to one of the best locations onshore in Denmark. In the sensitivity assessment calculations will be elaborated to assessment of the other onshore locations. Losses in the cables are not calculated, as the loss is insignificant little, as to the fact that the cables are very short. 4.2 Operation Regarding maintenance of the turbines a conservative estimate includes that half of the gearboxes are to be renewed after 10 years. In addition, change of oil, lubrication of gear and generator etc. are to be included. Twice a year, a technician must go to the farm for carrying out surveillance of turbines and cables. Therefore transportation by car 900 km/year through the lifetime of the farm has been included in the model. 4.3 LCA model In the model of the onshore wind farm, materials, manufacturing, transport, erection, operation, dismantling and scrapping of turbines and internal cables are included.

15 Page 15 of 54 Tjæreborg Turbine farm Vestas V80 10/60 kv transformer (Not included in LCA) 10 kv PEX onshore cable System limit Figure 4.3: the LCA. Grid connection system for Tjæreborg wind farm and statement of system boundaries of The lifetime of the turbines and the internal cables are set to be 20 years. VWS A/S states that the lifetime of onshore turbines is 20 years, and Elsam uses 20 years in the financial calculations. The turbines will probably be operating for several years but in the course of time the frequency of reparation and maintenance will increase, which may be a sign that after all the turbines will be taken out of operation after 20 years. 5. Data collection The collection of data has taken place in a very close co-operation with VWS A/S, so all information has been discussed with VWS A/S, and all assumptions of and approaches to materials and processes have been submitted and discussed. As regards the transmission part to the offshore wind farm, there has also been a close co-operation with Eltra, who has delivered data to this part. Concerning the turbines, the most significant environmental impacts will most typically arise during the manufacturing of the turbines and also the removal of the individual components, when the turbine shall be scrapped. On the other hand, the operational stage does not contribute significantly to the environmental impacts. Therefore the data collection has been concentrated in procuring as precise data as possible for the production and dismantling stages. To ease the model construction, the turbine system is divided into the component systems: tower nacelle blades foundation internal cables transformer station (off shore wind farm) onshore bringing (offshore wind farm).

16 Page 16 of 54 At the data collection, the target for included materials has been to cover approx 95% of the turbine s weight, as it has previously been proven that manufacturing of the turbine causes the major part of the environmental impacts in the whole life cycle of the turbine 3. This has also been the target in connection with data for the other parts of the farms. In connection with LCA-data for the used materials, it has been attempted to cover 95% of what regards all 1st level materials (i.e. materials used on VWS A/S factories, e.g. PrePreg for blades and steel for towers). As regards 2nd level materials (i.e. materials used by the sub-contractors, i.e. paint and content of substances in PrePreg) it has been a question of prioritising the selection of materials of which it has been important to collect information. 5.1 Procedures for data collection The data collection for the turbines has mainly been carried out by VWS A/S on the basis of the item lists for the two turbine types and drawings of various components. The item lists are brought up from the company s production management system, which furthermore contains information about material and weight of a very large part of incoming raw materials and semi-manufactured articles. As a starting point, all the item numbers on the item lists are included. As regards the items, where the information has not been immediately accessible it is assessed in each case whether it would be relevant to search for further information about weight and material composition. This has, among other things, caused that quite many screws and bolts and also minor electronic components have been unlisted. As regard large items as e.g. gearbox and generator, the information originate from the supplier. Information about overall conditions for the farms, transmission, foundations, electric power generation and for some part operation and maintenance is mainly gathered from Elsam and Elsam Engineering, who are owner and owner's consulting engineer, respectively. In all instances, the information is presented to and discussed with VWS A/S. Information about the transmission from the offshore wind farm is drawn from Eltra, as owner for this. Where possible the information about various materials is drawn from the database to UMIP, which have been extended through Elsam Engineering s work with LCAs during recent years. In cases where LCAdata was missing or the existing data has been inadequate, these data are searched through suppliers, internet and other LCA-studies. In some incidents, it has been necessary to make assumptions about the materials. The assumptions will be described in the individual sections below Workshop about reuse As part of the project a workshop has been held about the dismantling of the turbines and removal of components/materials. Participants in the workshop are people occupied with dismantling, removal and recycling. Besides VWS A/S and Elsam Engineering, the following parties were represented: H.J. Hansen (occupied with dismantling, recovery and electronic waste, Demex (occupied with dismantling), Waste Centre Denmark and RISØ, who is working with assessment of future turbines in life cycle perspective.

17 Page 17 of 54 The work of this project contains the following removal scenario: Material Scenario Steel 90% recycling Cast iron 90% recycling Stainless steel 90% recycling High-strength 90% recycling steel Cobber 90% recycling Aluminium 90% recycling Lead 90% recycling Glass fibre 100% deposit PVC-plastic 100% deposit Other plastic 100% incineration of waste Rubber 100% incineration of waste Table 5.1: Removal scenario for materials The above mentioned scenarios of removal data derive from literature data and from the workshop about recycling. However, some of the experts from the recycling industry expressed that the loss by recycling steel and metal is less than the 10%, which are used in several cases. The reason why the 10% is maintained is that there is much uncertainty about the figure and at the same time it is not known exactly if all materials can be divided totally, i.e. there might be a loss, before the recycling process is started Allocations As turbines only produce electricity and no heat, there is no need for allocation between more products. This simplifies the inventory Manufacturing of turbines VWS A/S energy consumption VWS A/S energy consumption for manufacturing turbines is set in connection with its Environmental Statement for 2001 (which not was published at the time when the collection of data ended) and indicates the total energy consumption in VWS A/S factories and offices. The energy consumption is stated as a key figure of the energy, which may be produced through the lifetime of the turbine (20 years), on all turbines manufactured at VWS A/S in The energy consumption covers the total consumption for all buildings and processes. So it has not been possible to divide the energy consumption among the individual turbine components. However, it is included as a total consumption of manufacturing of one turbine. The energy consumption includes electricity, heat, oil and gas. The allocation between these various energy forms is given by VWS A/S, who publishes the numbers in the Environmental Statement for VWS A/S has entered a purchase agreement about electricity for 2001, where the total free part 54% - is purchased from renewable energy sources, i.e. CO 2 -neutral, whereas the mandatory part - 46% - (prioritised production), which VWS A/S must buy, as 2001 was expected to consist of 44% renewable energy primary wind power. I.e., of the total electricity consumption 74% is from CO 2 -neutrale energy sources.

18 Page 18 of 54 The division of electricity used by VWS A/S has been taken from the expected division as shown in the Environmental Statement for , as the new numbers were not available. The division of electricity consumption regarding production methods are as follows (it is also indicated, how the individual systems are modelled in UMIP): Energy system Share Modelled as Not prioritized electricity: - water power 54% Norwegian electricity 1990 (99,7 % water power + 0,4% conventional power plants) Prioritized electricity: - wind power 20% Electricity from turbines (results from scheme design, PSO 1999) - other Danish system electricity 26% Danish system electricity 1997 (Division between heat and electricity is undertaken by means of energy quality) Table 5.2: View of division of VWS A/S electricity consumption Manufacturing of tower The towers for VWS A/S turbines are to some extent manufactured at VWS own factory in Varde, and the rest is purchased from sub-contractors. In this project only data from towers manufactured by VWS A/S has been used. The towers are manufactured in steel. The steel is delivered to VWS A/S in steel plates, which have already been pre-cut in a way that VWS A/S factories do not need to cut up the plates any further. In addition, there is no waste of steel. When the iron plates arrive at VWS A/S, the plates to the tower sections are rolled. Every section is welded lengthwise, then the individual sections are welded together. The subsequent treatments i.e. sandblasting and surface treatment of the towers are not performed at VWS A/S, but at sub-contractors. In this project the manufacturing at VWS A/S and the subsequent surface treatment at sub-contractors have been included. The manufacturing of steel plates has been modelled as steel plates from the UMIP-database, yet in a slightly modified version based on information from the Danish Steel Rolling Mill, which has also been used in the scheme design. The process, which has been found in the UMIP-data base for steel plates (89% primary), has been found not to be up-to-date and not to dispose of waste correctly. Oven slag is produced when manufacturing steel, and in the UMIP oven slag has been defined as hazardous waste. Actually, the oven slag is reused in the asphalt 5 industry and the oven slag has not been defined as hazardous waste in accordance with the Ministry of The Environment s Statutory Order no (Ann. No. 619 of 27/06/2000). Therefore a modified version of the steel process has been made, in which the oven slag has been defined as bulk waste in stead of as hazardous waste. A form of reusing the oven slag should have been included, but to simplify the data collection it has been included as bulk waste.

19 Page 19 of 54 Data regarding consumption of steel, welding wire, welding powder, paint and sand blasting originates from VWS A/S item lists and information from the sub-contractors Manufacturing of nacelle The nacelle consists of the nacelle cover, which includes generator, gear, main shaft, yaw system, flanges etc. The individual part components are not manufactured by VWS A/S, but are purchased from subcontractors, and then the final finishing (welding, metal cutting) and subsequent assembling take place at VWS A/S factories Gear According to the supplier the gear to a 2.0 MW turbine consists of cast iron, 7CrNiMoS6-steel and 31CrMoV9-steel, which constitute approx 95% of the material consumption for the gearbox. The final 5% of the material consumption is used for bearings, which consist of steel alloys. There is no available information about the composition of these materials. Since it has not been possible to get specified information about the 2 CrMo-steel types, data for stainless steel has been included instead. Stainless steel is the kind of steel which is most similar to the CrMo-steel and has already been entered into the UMIP. I.e. the gear is assumed to consist of 50% cast iron and 50% stainless steel. The supplier has not stated the energy consumption for manufacturing the gear. Therefore the energy consumption has been estimated based on information from a previous LCA of turbines 6 by up-scaling the energy consumption on the basis of the weight of the gear. Electric power generation in Europe has been used, as the gears are delivered by a supplier in Europe Generator According to the supplier, the generator consists of cast iron and various steel types such as steel plates and cobber. The manufacturer has not informed about the energy consumption during the manufacturing process, and therefore the energy consumption has also here been scaled on the basis of the weight of the generator from a previous LCA for turbines 6. Here is used European electricity too, as the generator is delivered from a European producer Nacelle cover The nacelle cover for a 2.0 MW wind turbine is manufactured of composite material. The Danish plastic industry has made an LCA-screening of various plastic materials including the manufacturing of cabins 7. Information from this has been used in present project Main shaft The main shaft for the wind turbine is manufactured of CrMo-steel. As the gear, this high power steel has been estimated with stainless steel. The energy consumption for the manufacturing process of the main shaft has not been available and therefore it has not been included.

20 Page 20 of Electricity switchboard The control system (approx 1,500 kg), which has been placed in the nacelle, consists of electricity switchboards. VWS A/S has provided information about the individual components weights, as well as the weight of the steel cabinets. It has not been possible to find LCA-data on all the electronic components. However, estimated average figures have been applied. Like this, a model of the consumption of the average electronic has been used based on a work report from the Danish Protection Agency about Elucidation about environmental declaration of contents of consumer electronic from knowledge to action 8. In this way the energy consumption for manufacturing of materials and assembling by VWS A/S have been included, but exclusive of manufacturing of part components at the subcontractors Other parts in nacelle In addition to above mentioned components the nacelle also consists of the following components: Yaw system. Bearing house. Main brackets. Torque arms (at gear). Hydraulic systems. Cables. All above parts are also represented in this life cycle assessment, as we have received data from VWS A/S about the individual part s weight and materials Manufacturing of rotor The blades are produced at VWS A/S factory in Nakskov. VWS A/S uses Prepreg, which is a glass fibre mat impregnated with epoxy resin. It has been difficult to obtain information from the manufacturer and supplier about the composition and the manufacturing of Prepreg. From the supplier s PrePreg safety data sheets it is assumed that Prepreg consists of approx 40% epoxy and 60% glass fibre. In the data base for the LCA-tools SimaPro, data has been found on Epoxy. The data is based on data from The Association of Plastics Manufacturers in Europe -APME 9 The data has been transferred to the UMIP. However, there is incomplete data or lacking data on certain materials in the UMIP-data base, and unfortunately the epoxy data is incomplete which gives rise to some uncertainty. Still, the available data and estimated time are regarded to be the best data possible. If the environmental impacts are calculated from epoxy in SimaPro with the UMIP-method and in UMIP, respectively, it is found that most of the impacts to some extent are similar, while as regard to bulk waste there are differences on human toxicity, corresponding to a factor of Some of the differences are due to the different data basis in the 2 data bases, missing data in the UMIP-data base compared with the SimaPro data bases as well as differences in the calculation methods. Taking all this into consideration, it is still estimated that the epoxy data used in the present project is acceptable.

21 Page 21 of 54 The blades are primarily manufactured of PrePreg, which is uncured by using heat and vacuum. A blade is constructed over a spar/root joint, which is made of Prepreg. The blade shell, which consists of two PrePreg pieces, is placed over the spar and glued together around the spar. Prepreg is delivered to VWS A/S on rolls. The Prepreg rolls are covered with separation film. At VWS A/S the Prepreg is cut into appropriate pieces to the spar and the blade shell. PUR-glue and other materials are used to assemble the blade shells and the spars. Sufficient LCA-data on PUR-glue has been impossible to obtain, but from the manufacturer s environmental accounts it has been possible to procure some data, which is estimated to be relatively adequate. The environmental accounts do, however, cover several types of glue from the producer, for which reason only average data has been used in cases, where it has not been obvious to omit content substances such as solvents. The spinner is also included in the rotor statement. Finished part components for the spinner are delivered to VWS A/S, who is in charge of the assembling. The spinner consists of nose cone supports, blade hub, torque arm plates, torque arm shafts and torque arm blocks. Furthermore, the spinner is constructed of fibre glass-reinforced polyester. VWS A/S has provided information about all components, material types and weights of these. The glass fibre has been modelled as described under the Nacelle Cover. CrNiMo-steel is equivalent to stainless steel. Apart from the above mentioned, VWS A/S has informed that some auxiliary materials such as vacuum fleece and various plastic films are used Waste from the blade manufacturing process When using PrePreg in the manufacturing process up to 10% of the PrePreg turns into waste due to cutoffs. Previously, the waste was sent to incineration, but this no longer possible. In the future the waste will be reused or uncured and deposited. As both processes are very new, it has not been possible to include them in this environmental assessment. VWS A/S disposes of separation film as combustible waste. The auxiliary materials such as vacuum fleece, vacuum foil and slip and bleeding foil, will all be removed before assembling of the blades. The vacuum fleece has collected surplus epoxy, however, the extent of this is unknown. Auxiliary materials are disposed as combustible waste Manufacturing of onshore foundation The foundation for the onshore turbine consists of plate foundations made with reinforced concrete. Typically, the size is metres and 2 metres deep. The foundation is concreted in situ. After excavation the hole is filled with approx 350 m 3 concrete with approx 27 tons of reinforcement. Transport of concrete and reinforcement to the farm area has not been included. Only materials are included in the model Manufacturing of offshore foundation At the time of the data collection for this project no real practical experience was available in Denmark regarding establishment of steel foundations for offshore turbines. The following considerations are primarily referred to the tender documents for the foundation agreement at Horns Reef.

22 Page 22 of 54 It is presumed that the turbine is placed on metres of water, calculated from sea surface to sea bottom at average water level. Like this, secure dimensioning has been chosen in proportion to the average water dept at Horns Reef at metres. The foundation consists of a foundation pile, a transition piece, boat landing platform, platform and cathode protection. As the dimensions for the foundation pile may fluctuate due to various sea depths, different assumptions are made as regard the dimension of the foundation. The dimensions are as follows: Foundation pile Length Diameter Thickness : High-strength steel : 29,700 mm : 4,000 mm : 30 mm, 45 mm, 50 mm Dimensions for the transition piece are as follows: Length : 17,000 mm Diameter : 4,240 mm (bund), 4,000 mm (top) Thickness : 40 mm and 50 mm Manufacturing of foundation piles and transition piece. The production of the foundation pile and the transition piece is based on above-mentioned tender materials. Furthermore, experience from previous LCA-studies on various processes as welding, sand blasting etc. and from manufacturing the turbine tower has been used. The quantity of steel has been determined from the tender material. The energy consumption has been estimated from a previous LCA-study on turbines regarding production of tower. It has been assumed that the energy consumption is linear correlated to the steel tonnage. Furthermore, experience based on data from the LCA-study about material consumption for the welding process has been used. It has not been possible to determine other parameters for the manufacturing process of the pile. For the foundation, the following data has been used: steel, energy consumption, welding, acetylene, tetrene, atal-6, welding powder, oxygen and argon Surface treatment The steel is sand blasted, cf. tender material. Incoming quantities of sand has been stated. For the coating of the steel a 2-component thick film (epoxy) coating has been stated. Regarding the paint data has been provided from the supplier s green accounting, and this data has been attempted to be modelled in the UMIP. However, more incoming substances have been used, where it has been difficult to find data. Some data has been omitted, whereas the most important data has been found in e.g. SimaPro s data base. It has not been possible to get information from the suppliers about the energy consumption and emissions obtained from the processes Assembling of foundation piles and transition piece The transition piece has a larger dimension than the foundation pile. A concrete based material with high-strength quality has been used for coupling the pile and the transition piece. However, it has not been possible to obtain data about the manufacturing of this special concrete material within the deadline of the project. Instead data on production of ordinary concrete has been used. Data refers to Aalborg Portland s environmental statement of

23 Page 23 of Boat landing platform and platform Both the boat landing platform and the platform have are manufactured in steel and entered with quantities found during the projecting the foundation Cathode protection In order to minimize corrosion the foundation pile has been cathode protected inside as well as outside. Passive solutions of cathode protection have been selected, which means that no applied power is needed for the protection. I.e. we use sacrificial anodes made of aluminium, where the sacrificial material must be sufficient to protect the pile in its lifetime. In connection with the erection of offshore turbines at Horns Reef the dimension of the cathode protection (inside and outside) has been calculated. The quantity of material may vary depending on the water depth. A water depth of metres has been estimated. The lifetime of the cathode protection has been set to be 30 years. However, the lifetime has been recalculated to 20 years, which also applies for the rest of turbine. During the dismantling and scrapping 47% of Al will be unexploited and the part, which has been exploited will be included in the operation of the foundations. For the protection system, all incoming cables are included, e.g. the cobber in the cables. It has not been possible to include a complete material composition and/or the lifecycle of the cables. All cables are made of cobber and are included in the model as pure cobber Manufacturing of internal farm cables to offshore wind farm 32 kv PEX submarine cables are used as internal farm cables, i.e. between the turbines and between the turbine farms and the 32/150 kv transformers. The 95 and 150 mm 2 cables are manufactured by the Oslofjorden, and the 400 mm 2 cable is manufactured in Hanover. Data regarding the manufacturing of the cable has been obtained from the supplier s data sheet for this cable. The cables contain cobber, lead, steel and insulator. The insulator is assumed to be polyethylene. All the materials are known in the UMIP data base. During the manufacturing process we have estimated with 50 km onshore transport from the material supplier to the cable factory Manufacturing of transformer station to offshore wind farm The foundation for the platform, which has a 40-year lifetime, consists of three piles; two of these with a diameter of approx 1,6 m and a pile with a diameter of 2,3 m. The three foundation piles are mutually combined via lattice girders. The platform has been placed approx 14 m above mean water level and holds a height of approx 7 m. The ground dimensions are m. The steel superstructure will be covered on the sides to create shelter on the platform. On top of the platform approx 23 m above mean water level a helicopter platform has been placed with a diameter of approx 20 m. The superstructure is assembled onshore and transported to the offshore wind farm as one module. The module is placed on the substructure by means of a floating crane.

24 Page 24 of 54 The foundation and the platform consist of steel, stainless steel, aluminium and reinforced concrete, and UMIP-database has data on all these materials. The transformer primarily consists of oil, tin, cobber and steel. LCA-data can be found in the UMIP regarding these materials Manufacturing of 150 kv PEX submarine-/onshore cable and SF6-system for offshore wind farm A 150 kv PEX cable with a 40-year lifetime is used for transferring electricity from the offshore transformer station to the connection of the power transmission grid via the cable transition station at Hvidbjerg Seashore south of Oksby. The length of the cable from the offshore transformer station to the cable transition station is approx 20 km; and from the transition station to the connection of the 150 kv transmission grid there is approx 34 km. In other words 20 km of the cables are submarine cables and the remaining 34 km are onshore cables. The submarine cable starts at the transformer platform at the offshore wind farm and ends onshore by Hvidbjerg Seashore south of Oksby. On the coast the cable is pulled approx 1,000 metres onshore, and subsequently the submarine cable is connected to the onshore cable in a cable transition station. And there the onshore cable is wired to the 150 kv-transformer station on Karlsgårde north of Varde. The cable transition station at Oksby connects the submarine cable from the offshore wind farm to the onshore cable. Apart from the transition between the two cable types, the transition station also contains a fixed coupled output coil for compensation of the cable s generated reactive effect. The cable transition station has been established as a capsular SF6-system in order to minimise the dimension of the site. The site has been placed in a building of approx 200 m 2. This building is very simple and has not been included in this LCA, as it has been estimated to be insignificant. For the manufacturing of the cable transition station primarily cast iron, oil, cobber and steel has been used. The submarine cable in the trace will be a 150 kv three-conductor, PEX cable equipped with a sea armouring of steel wires. The submarine cable primarily consists of lead, cobber, steel and plastic. The onshore cable will be equipped with one-conductor PEX isolated cables with mm 2. Each of the three one-conductor cables weighs approx 9 kilos/m and has a diameter of 90 mm. The onshore cable is manufactured at one of the ABB Group s cable factories in Karlskrona. The primary materials in the onshore cable are aluminium, cobber and plastic and also sand and concrete for the cable channel. During the manufacturing process a 50 km onshore transportation has been estimated from the material supplier to the cable factory.