3. Site Selection Methodology and Consideration of Alternatives
- A summary of the considerations for site selection and alternatives of the Proposed Development is outlined in this section. The Offshore EIAR will outline the stages of site selection and Project Description refinement that have been carried out in order to establish the Proposed Development Array Area, proposed ECC and landfall, and key parameters. Furthermore, the Offshore EIAR will set out any refinements to the Proposed Development that have taken place as a result of the EIA process and in response to consultation and stakeholder feedback and will describe the main alternatives that have been considered as part of this process.
- Sections 3.2 Open ▸ and 3.3 Open ▸ outline the process behind the identification of the Proposed Development Array Area and the point of landfall.
3.2. Site Selection and Consideration of Alternatives
3.2.1. Firth of Forth Round 3 Zone
- The Proposed Development is located within the former Firth of Forth Zone (the Zone). Site selection for the Proposed Development has comprised the following stages:
- initial zone selection in 2008, undertaken by TCE following their SEA and Round 3 zone identification process;
- followed by the subsequent stages undertaken by SSER:
– identification of three development phases within the Firth of Forth Zone (Seagreen Alpha/Bravo, Berwick Bank Wind Farm, Marr Bank Wind Farm;
– Zone Appraisal and Planning (ZAP): a discretionary, non-statutory process to aid developers in managing development risks within their zones;
– identification of the initial Berwick Bank Wind Farm and Marr Bank Wind Farm proposals within the former Firth of Forth Zone;
– identification of the Proposed Development within the former Firth of Forth Zone following analysis of environmental, technical and engineering constraints.
- The Round 3 offshore wind development programme instigated by TCE in 2008 was designed to facilitate delivery of a larger scale offshore wind farm development than had previously occurred in the UK. Suitable areas for the development of offshore wind were assessed through a statutory process of SEA undertaken by DECC, now BEIS.
- In 2009, Seagreen Wind Energy Limited was awarded development rights to Round 3 Zone 2 (named ‘Firth of Forth Zone’), and subsequently Seagreen and TCE entered into a Zone Development Agreement (ZDA) with a target Zone generation capacity of circa 3.5 GW.
- The ZDA granted Seagreen certain seabed rights within the Firth of Forth Zone, such as to identify specific areas for the development of offshore wind farms. Although the boundary of the Firth of Forth Zone was fixed, development phase and project boundaries remained flexible. The key considerations for the selection of the preferred offshore wind farm sites within the Firth of Forth Zone related to the environmental, engineering and economic constraints. For example, avoiding areas which are not economically viable due to insufficient wind resource, or unsuitable areas due to seabed geology.
- Seagreen opted for a phased approach to the delivery of the projects within the Firth of Forth Zone to achieve the target capacity. This approach involved prioritising areas considered to have the least potential constraints and considering the practicalities of resourcing delivery of the target capacity for the Firth of Forth Zone. To support the definition of phases and project boundaries rationally and strategically, Seagreen adopted the ZAP approach.
- ZAP was a term advocated by TCE to describe the non-statutory strategic approach to zone design, project identification and consent. The ZAP process allowed developers to have greater control over the way a zone is developed and encourages a high-level strategic approach to planning and stakeholder engagement of the zone in terms of environmental, social and economic effects (particularly cumulative effects). The Seagreen ZAP followed an iterative process throughout the projects within the Firth of Forth Zone.
- The initial ZAP report (Seagreen, 2010a) informed the Zone Consenting Strategy (Seagreen, 2010b) and ranked the sites on the level of constraint and ability to construct. The strategy was to construct seven offshore wind farms within three phases (Seagreen, 2011). An updated ZAP report in 2011 provided recommendations for the Phase 1 (Seagreen Alpha/Bravo) project boundaries and indicative Phase 2 (initial Berwick Bank Wind Farm Proposal and the Marr Bank Wind Farm Proposal) and Phase 3 project boundaries, aided by identification of environmental constraint within the Zone (Seagreen, 2011). The Phase 1 project, consisting of Project Alpha and Project Bravo, were awarded consent in November 2017, and a 15-year CfD was awarded in September 2019 for 42% of the total project capacity (1.075 GW).
- A second update of the ZAP report in 2014 provided further refined boundaries for Phase 2 projects, building on from increased understanding of constraints from the Seagreen Alpha/Bravo EIA (Seagreen, 2014). Phase 2 of the Firth of Forth Zone was proposed with two projects: the initial Berwick Bank Wind Farm (previous project) and Marr Bank Wind Farm. Subsequently in 2019, the Firth of Forth ZDA was terminated, with AfLs now agreed with CES for Seagreen Alpha/Bravo (consisting of Seagreen Alpha and Seagreen Bravo), initial Berwick Bank Wind Farm proposal and initial Marr Bank Wind Farm (which is now included within the current Berwick Bank Wind Farm Proposed Development). The AfLs for the initial Berwick Bank Wind Farm (previous project) and Marr Bank Wind Farm are shown in Figure 3.1 Open ▸ .
- In August 2020, SSER (via its subsidiary Berwick Bank Wind Limited) consulted on the initial Berwick Bank Wind Farm Offshore EIA Scoping Report and received a Scoping Opinion from the Scottish Ministers in March 2021 (Scottish Government, 2021). The initial Berwick Bank Wind Farm Offshore EIA Scoping Opinion has been used to inform this Proposed Development Offshore EIA Scoping Report Amendments to layout, flow and content of this Offshore EIA Scoping report have been made following stakeholder feedback.
3.2.2. Berwick Bank Wind Farm Revised Boundary
Following a detailed consideration of the initial Berwick Bank Wind Farm and Marr Bank Wind Farm Proposed Development Array Area boundaries, SSER has revised their approach to the consent application and the proposed boundaries for both projects and amalgamated the two projects into one project - Berwick Bank Wind Farm. To inform this boundary review exercise, a holistic analysis of both environmental and engineering constraints was undertaken (including the analysis of available survey data), which aimed to balance maximising the generation of renewable energy, minimising potential environmental impacts and minimising engineering constraints. The Proposed Development Array Area has been reduced by 9% when compared to the previous Berwick Bank Wind Farm and Marr Bank Wind Farm Proposed Development Array Area boundaries. The reduction in area has the benefit of avoiding key ornithological areas as well as mitigating potential navigation issues and reducing overlap with the Firth of Forth Banks Complex MPA. Benefits are also anticipated across other environmental topics as a result in the reduction in the overall Proposed Development Array Area. No significant changes have been made to the ECC or landfall.
Figure 3.1: Berwick Bank AfL and Marr Bank AfL, and the Berwick Bank Wind Farm Boundary
- The AfLs for the initial Berwick Bank Wind Farm (previous project) and Marr Bank Wind Farm are shown in Figure 3.1 Open ▸ with the revised Proposed Development Array Area boundary overlaid.
- The Offshore EIAR will further describe the background to the former Firth of Forth Zone and the evolution of the Proposed Development. In addition, the Offshore EIAR will outline the process that SSER has followed to identify potential wind turbine layouts within the Proposed Development Array Area, the main alternatives that were considered and the rationale for the selection of the layout considering any modifications identified during consultation. The final layout of the wind turbines will be confirmed at the final design stage (post-application).
3.2.3. Transmission Cables and Associated Infrastructure
- To allow for connection between the Proposed Development Array Area and the onshore substation, SSER will install export cables between the Proposed Development Array Area and the onshore grid connection point. The generated electricity from the wind turbines will be transmitted onshore via buried high-voltage cables. These cables will be either High Voltage Alternating Current (HVAC) or High Voltage Direct Current (HVDC). The parameters of the export cable will be confirmed prior to EIA Report submission, and final design will be dependent on final wind turbine and electrical design, as well as a detailed analysis of the costs, technical aspects and available technology of the various options.
- The proposed ECC (ECC) has been identified between the Proposed Development Array Area and the two landfall locations on the East Lothian coast are being considered, Thorntonloch Landfall and Skateraw Landfall. Only one of the cable landfalls will be selected. A grid connection point has been confirmed at Branxton, south west of Torness Power station with an existing grid connection agreement.
- The initial selection of the proposed ECC was conducted by desktop and site-based study using the current best available information on constraints and publicly available information on the proximal Neart Na Gaoithe (NnG) offshore wind farm, including site boundary, indicative proposed ECC, and onshore cable route red line boundary. Geophysical surveys have been carried out on the part of the cable corridor from the Proposed Development Array Area to the proposed Thorntonloch Landfall at Thorntonloch Beach. The two proposed landfalls shown in Figure 3.2 Open ▸ were selected from an original selection of seven landfalls.
- The indicative cable corridor shown in Figure 3.2 Open ▸ is a direct route from the onshore grid connection to the Proposed Development Array Area. The proposed ECC then allows options in the nearshore area to route to the two potential landfall sites. SSER intends to refine this to only one landfall option by the submission of the application.
3.3. Landfall Locations
- The Project has a grid connection agreement with National Grid Electricity System Operator at a point close to the existing Branxton substation compound, approximately 8 km south of Dunbar.
- SSER considered a number of landfall options within the vicinity of Branxton, which were evaluated from an engineering, consents (planning and environment), land use and cost perspective. Two preferred landfall locations have been identified on the East Lothian coast, one at Thorntonloch and one at Skateraw (Figure 3.2 Open ▸ ). SSER intends to refine this to only one landfall option by the submission of the application.