Galloper Wind Farm Project · Final Report Chapter 6 – Page 1 October 2011 6 SITE SELECTION AND ALTERNATIVES 6.1 Introduction 6.1.1 This Chapter of the Environmental Statement (ES)

Galloper Wind Farm ProjectEnvironmental Statement – Chapter 6: Site Selection and

AlternativesOctober 2011

Document Reference – 5.2.6

Galloper Wind Farm Limited

Galloper Wind Farm 9V3083/R01/303424/Exet

Final Report - i - October 2011

Document title Galloper Wind Farm Project

Environmental Statement – Chapter 6: Site

Selection and Alternatives

Document short title Galloper Wind Farm ES

Document Reference 5.2.6

Regulation Reference APFP Regulations, 5(2)(a)

Version 4

Status Final Report

Date October 2011

Project name Galloper Wind Farm Project

Client Galloper Wind Farm Limited

Royal Haskoning

Reference

9V3083/R01/303424/Exet

Drafted by Peter Gaches, Jon Allen et al.

GWFL Approved by Kate Harvey

Date/initials approval KH 01.11.2011


Final Report - iii - October 2011

CONTENTS Page

6 SITE SELECTION AND ALTERNATIVES 1 6.1 Introduction 1 6.2 Guidance and Consultation 2 6.3 Consultation 4 6.4 Offshore and Landfall Considerations 4 6.5 GWF Compound 16 6.6 Transmission Compound 25 6.7 Connection to the National Transmission System 29 6.8 Cable Corridors 30 6.9 References 33


Final Report Chapter 6 – Page 1 October 2011

6 SITE SELECTION AND ALTERNATIVES

6.1 Introduction

6.1.1 This Chapter of the Environmental Statement (ES) describes the approach taken to identify the preferred site for Galloper Wind Farm (GWF). The process included consideration of both the offshore and onshore developments, and associated infrastructure.

6.1.2 The offshore development comprises up to 140 wind turbines generators (WTG) depending on the rotor diameter of the WTG (typically capacities in the range 3.6MW – 7MW), primarily located on the seaward side of the existing Greater Gabbard Offshore Wind Farm (GGOWF) site. There would be up to five offshore platforms that would be used to house the offshore electricity substations, collector stations and/or associated accommodation, as well as up to three offshore meteorological masts for monitoring wind speeds. In order to connect the WTGS to the offshore substations, buried subsea inter and intra-array cables are required. In addition, there would be up to three buried subsea cables linking the offshore development to the land. The offshore site was broadly defined during The Crown Estate bidding process.

6.1.3 The onshore development comprises the infrastructure required to connect the GWF offshore cable network array to the national electricity transmission system. The onshore infrastructure comprises:

A 132kV onshore GWF compound and a 132kV/400kV onshore transmission compound, which together are referred to as the “GWF substation”;

Cable landing on Sizewell Beach; Onshore underground cabling from the landfall on Sizewell Beach to

the GWF substation; Onshore transition bays where the offshore export cables from the

WTGs are joined to the onshore cables; Onshore underground cabling from the transmission compound

connecting into the existing Greater Gabbard Offshore Wind Farm (GGOWF) 132kV cables (which run from Sizewell B to the GGOWF substation);

Alterations to existing electricity towers and overhead line connections;

Transmission sealing end compounds adjacent to the existing electricity towers;

Onshore cabling from the 132kV/400kV transmission compound to the sealing end compounds;

Connection from the onshore 400kV cabling from the GWF substation to the overhead transmission via a gantry or anchor block system located within the sealing end compounds;

Temporary works and laydown areas; and,



Permanent and temporary access roads.

6.1.4 See Chapter 5 Project Details for more information on the onshore and offshore infrastructure.

6.2 Guidance and Consultation

Legislation, policy and guidance

6.2.1 National Policy Statements (NPS) provide the primary basis on which the Infrastructure Planning Commission (IPC) is required to make its decisions. In preparing this chapter the following NPS were reviewed:

Overarching National Policy Statement (NPS) for Energy (EN-1) DECC, 2011a);

6.2.2 With regard assessing alternatives paragraph 4.4.1 of NPS EN-1 states that:

‘As in any planning case, the relevance or otherwise to the decision-making process of the existence (or alleged existence) of alternatives to the proposed development is in the first instance a matter of law, detailed guidance on which falls outside the scope of this NPS. From a policy perspective this NPS does not contain any general requirement to consider alternatives or to establish whether the proposed project represents the best option.’

6.2.3 Paragraph 4.4.2 of NPS-EN1 also goes on to state that:

‘However…applicants are obliged to include in their ES, as a matter of fact, information about the main alternatives they have studied. This should include an indication of the main reasons for the applicant’s choice, taking into account the environmental, social and economic effects and including, where relevant, technical and commercial feasibility.’

6.2.4 Where an NSIP takes place in a nationally designated area, such as an Area of Outstanding Natural Beauty (AONB) as the onshore aspects of this proposed development do, paragraph 5.9.10 of NPS EN-1 states that:

‘...the IPC may grant development consent in these areas in exceptional circumstances. The development should be demonstrated to be in the public interest and consideration of such applications should include an assessment of...the cost of, and scope for, developing elsewhere outside the designated area or meeting the need for it in some other way, taking account of the policy on alternatives set out in Section 4.4.’.



6.2.5 This Chapter of the ES addresses the alternatives that were considered for GWF, with particular focus on the associated, land based, infrastructure.

Other planning considerations

6.2.6 The Energy NPSs are the primary decision-making guidance documents for the IPC on nationally significant energy projects in England and Wales. Other national and local planning policy, particularly in relation to locating the development in an AONB is set out in the following sections.

6.2.7 Planning Policy Statement (PPS) 22 (Renewable Energy) allows that planning permission for renewable energy projects can be granted in an AONB where it can be demonstrated that the objectives of the AONB will not be compromised by the development, and any significant adverse effects on the qualities for which the area has been designated are clearly outweighed by the environmental, social and economic benefits.

6.2.8 Paragraph 11 of PPS22 states: “In sites with nationally recognised designations (Sites of Special Scientific Interest, National Nature Reserves, National Parks, Areas of Outstanding Natural Beauty, Heritage Coasts, Scheduled Monuments, Conservation Areas, Listed Buildings, Registered Historic Battlefields and Registered Parks and Gardens) planning permission for renewable energy projects should only be granted where it can be demonstrated that the objectives of designation of the area will not be compromised by the development, and any significant adverse effects on the qualities for which the area has been designated are clearly outweighed by the environmental, social and economic benefits.”

6.2.9 Suffolk Coastal District Council’s (SCDC) local planning policy with regard to the AONB also acknowledges that development in the AONB is acceptable where there is an overriding national need for the development in the location, and it can be demonstrated that there is a lack of acceptable alternative sites.

6.2.10 Policy AP12 of the Suffolk Coastal Local Plan (2006) states that: “In order to safeguard the quality of the landscape within the Suffolk Coast and Heaths AONB, the District Council will not grant planning permission for any proposed development which would have a significant adverse impact on the landscape. Only proven national interest and lack of alternative sites can justify an exception.”

6.2.11 In deciding on the preferred locations for the GWF substation, comprising the GWF compound, the transmission compound and associated infrastructure, both GWFL and National Grid Electricity Transmission (NGET) have been mindful of existing planning precedent with regard to the AONB. Of particular note are the Sizewell Nuclear Power Stations (Sizewell A and B) and the effect that these developments have had on the AONB in the Sizewell vicinity. Also of note is the GGOWF substation, which is located in the AONB to the north of Sizewell Gap. A planning application for this substation was approved by SCDC in 2006 despite the substation being located within the



AONB ‘in recognition of the overriding need to secure renewable energy sources.’ A previous application (C05/1949/FUL) for a substation located to the south of Sizewell Gap was refused by SCDC in 2006, on the grounds that it would ‘have a significant adverse impact on the visual amenity and landscape character of that part of the AONB’.

6.3 Consultation

6.3.1 Following the submission of the GWF Scoping Report in July 2010 (SSE Renewables and RWE Npower Renewables Limited, 2010), which identified two potential locations for the onshore substation, the IPC requested that further information be provided to support the application regarding onshore site selection (IPC, August 2010).

6.3.2 Within the same scoping opinion, Suffolk County Council and Suffolk Coastal District Council (SCDC) also requested that additional detail be provided regarding the site selection process.

6.3.3 Specifically SCDC stated that GWFL had provided insufficient detail as to the selection of the two onshore substation location options presented in the Scoping Report and that additional information was required regarding the study area and what alternative sites for the substation had been considered, including those outside the AONB.

6.3.4 GWFL and NGET have separately carried out further consultation, following the scoping opinion, with the local community with regard to the potential locations of the onshore infrastructure. The outcomes of these consultations are summarised later in this Chapter. Reports on these consultation exercises can be obtained from GWFL’s website (www.galloperwindfarm.com).

6.3.5 Following the onshore substation community consultation, GWFL undertook statutory consultation. Where relevant to site selection and alternatives, this is summarised in the following sections. Full details of this consultation are set out in the Consultation Report included with the application.

6.4 Offshore and Landfall Considerations

6.4.1 The proposed GWF development site presents the culmination of a number of years of investigatory work by GWFL following financial close for GGOWF.

6.4.2 In 2008, GWFL commissioned a feasibility study into the potential for further offshore wind farm development in the vicinity of GGOWF. This process identified two areas adjacent and immediately to the east of the existing GGOWF site together with a site further to the southwest of the GGOWF in the Outer Thames Estuary.

6.4.3 In 2009, The Crown Estate opened a formal bidding process for extension projects to Round 1 and 2 sites, colloquially known as Round 2.5, (as discussed in Chapter 1 Introduction and Chapter 2 Project Need, Policy



Framework and Guidance). The Crown Estate’s requirements for Round 2.5 developments had significant influence on the site selection for GWF as the criteria stated that the extension site must:

Be of an appropriate scale to the original site;

Take into consideration environmental parameters and other constraints;

Share a substantial part of one or more boundaries with the original site; and

Demonstrate synergies with the original site, e.g. of construction, operation, improvement of economics and / or grid connectivity.

6.4.4 As a consequence of The Crown Estate’s requirements, site selection for GWF was refined for the formal Round 2.5 bid submission. The area to the southwest was dropped from consideration as it did not share a project boundary with GGOWF. The two extensions to GGOWF were maintained as they were in line with the criteria.

6.4.5 The Crown Estate awarded the site in 2010 and the strategic area for the offshore elements of the development was confirmed as part of this process. Although the final scheme layout within the DCO red line will be subject to detailed design following the approval process (as per the Rochdale Envelope approach, see Chapter 4 EIA process for further details), consultations that have taken place with key stakeholders as part of the iterative Environmental Impact Assessment (EIA) process have assisted in refining the application boundary. Boundary refinements have also responded to further investigation into the existing environmental and human parameters of the site.

6.4.6 The eastern boundaries of Areas A and B (see Figure 1.1 in Chapter 1) were reduced, following initial early consultation due to concerns relating to shipping, ornithology and technological constraints posed by deep water, whilst the northern boundary of Area A was reduced to lessen conflict with the Round 3 East Anglia Zone and shipping.

6.4.7 Figure 6.1 shows the initial site boundary for the offshore wind farm that was under consideration, in relation to the current site boundary.

6.4.8 Fixing the final application boundary involved striking a balance between responding to technical and environmental constraints, and external consultation, while maintaining critical design and layout flexibility. The need for that flexibility is explained briefly in Chapters 4 and 5 of this ES, and in more detail in the Explanatory Memorandum. The actual extent of the flexibility is explained in Chapter 5. As is noted, on some possible scheme layouts parts of the application site would not be used. However, the commercial, technical and environmental drivers which apply during the post-consent design optimisation process mean that the application boundary needs to allow for this possibility to ensure the success of the project. In this



regard it should be noted that the sea area for GGOWF, for an identically sized scheme (i.e. 504MW) is broadly similar to GWF and the full consented area has been used for construction.

6.4.9 The GWF export cable route has been based on the route of the GGOWF export cable, avoiding aggregate areas, and a landfall location close to the national grid connection point for GWF that avoids significant physical and environmental constraints. Further information on the landfall location and national grid connection point is set out in the following sections.

6.4.10 The justification for locating the GWF export cable corridor adjacent to the GGOWF is:

To minimise the footprint on the seabed by allowing GWF export cables to enter into the GGOWF corridor;

It is the area that has been awarded by The Crown Estate in the Agreement for Lease;

The GWF export cables need to come ashore at a similar location to GGOWF; and

A geotechnical survey has been undertaken on the GGOWF corridor and the seabed conditions of the adjacent GWF corridor are therefore more widely understood than a completely new area.

6.4.11 The GGOWF cable corridor is 500m in width. Up to 1,000m has been allocated for GWF due to the aggregate application area – Shipwash (507/5), which is in the middle of the export cable corridor.

6.4.12 The GWF corridor is located to the North of the GGOWF route due to the aggregate application area, Shipwash (507/6), being immediately adjacent to the GGOWF, which eliminates the possibility of locating the corridor to the South of the GGOWF route, see Figure 6.2.







6.4.13 The offshore transmission technology will be 132kV AC. This technology was preferred to a high voltage direct current (HVDC) offshore transmission technology for a number of reasons, including:

Wind farms connected via HVDC link are expected to have lower system availability and higher electrical losses;

HVDC would have significant implications for the existing connection agreement and program (timescales of connecting to the onshore transmission system with HVDC link are expected to be longer than 132kV AC option by at least 1 year);

A transmission system based on HVDC technology is expected to have significantly higher cost than equivalent AC system; and,

The limited track record of HVDC technology in offshore wind applications.

Grid connection point

6.4.14 In December 2009, GWFL secured a Grid Connection Agreement from NGET, i.e. the location where the electricity generated by GWF is connected to the 400kV national electricity network. This ‘Grid Connection Agreement’ was located at Sizewell.

6.4.15 A Sizewell grid connection was chosen by NGET over other options at Shotley (with a connection to Bramford substation) and Bradwell which had previously been considered for GGOWF. Both Bradwell and Shotley would involve longer sub-sea connections than to Sizewell and would affect foreshores and estuarine environments designated for their nature conservation interest at national and international level. At Bradwell this would involve cable crossings of Site of Special Scientific Interest (SSSI) and Special Area of Conservation (SAC) and, at Shotley, crossings of SSSI, Ramsar and Special Protection Area (SPA) designated areas. Onshore works at Shotley and the connection to Bramford would affect the Dedham Vale and Stour Valley AONB. From Shotley, a 25km overhead line connection to Bramford substation would be required, while at Bradwell, proposals would conflict with a contracted connection for a nuclear power station. This would result in the need for a bigger substation and a new 38km overhead line from Bradwell to Rayleigh substation. While there is a history of power generation and transmission infrastructure at both Sizewell and Bradwell, Shotley would involve introducing new infrastructure into an area currently unaffected by such works and activities.

6.4.16 Bringing the cables ashore at other locations from those referred to above would require more extensive onshore works to connect locations remote from the existing transmission network by means of new 400kV overhead lines of the order of 40km in length across areas of Suffolk some of which are subject to statutory environmental designations.

6.4.17 The Sizewell area is itself subject to a number of statutory environmental designations, including AONB and Heritage Coast designations covering the



coastal strip and SSSI and SPA designations. However the area has the advantage that existing electricity generation and transmission infrastructure is in place and no significant modifications to overhead lines are required. The area has also been identified as the location for the proposed Sizewell C nuclear power station.

Landfall point

6.4.18 The location for the cable landfall is to the north of the GGOWF cable landfall on Sizewell Beach on the stretch of coastline between Coastguard Cottages and Cliff House (the cable landfall location is shown in Plate 6.1). This landfall location was selected due to:

The need to be in reasonable proximity to the agreed grid connection point at Sizewell;

Restricted or no opportunity for landfall further to the north of the selected site due to the presence of the Sizewell A and B power stations and the Sizewell C nominated area, and protected nature conservation sites (Minsmere-Walberswick Ramsar, SPA, Minsmere to Walberswick Heaths & Marshes SAC and SSSI;

Limited opportunities to the south of the selected landfall site due to areas of existing development and protected nature conservation sites (Leiston – Aldeburgh SSSI, Sandlings SPA);

The need to avoid existing residential properties, including Coastguard Cottages;

Offshore proposed aggregate areas that influence the route to shore;

The need to avoid exclusion zones surrounding the Sizewell Power Station outfalls and other cabling works, including those associated with GGOWF; and

The need to avoid areas of known archaeological importance.

The immediate constraints around the landfall site are shown in Figure 6.3.





Plate 6.1 View illustrating proposed area for GWF cable landfall – looking north with Sizewell Power Stations visible in the distance

6.4.19 Given the constraints shown in Figure 6.3 a cable landfall area at Sizewell, between the existing GGOWL cable corridor and Coastguard Cottages was chosen and consulted on during the statutory consultation period (13th June – 14th July 2011). As a result of consultation responses, the cable landfall in the application has been refined by reducing the cable corridor extent at the landfall location such that it is further from Coastguard Cottages. The landfall locations included in consultation and that the application are shown in Figure 6.4.





Onshore option appraisal

Substation site option appraisals

6.4.20 There are two main elements required for the GWF substation, a 132kV onshore GWF compound and a 132kV/400kV onshore transmission compound. The former will be built and operated by GWFL (and any subsequent Offshore Transmission Owner), the latter by NGET. Although locating both of these compounds in adjacent locations has advantages (such as reduced cable lengths and locating development close to each other) there are no overriding technical reasons why they must be adjacent. In light of this both GWFL and NGET undertook separate options appraisals and non-statutory consultations on the location of the compounds.

6.4.21 The basis for both option appraisals was the consideration of the NGET guidance for the siting of substations, known as the Horlock Rules (National Grid, 2006). The guidance set out in the Horlock Rules establishes a set of key criteria to assist those responsible for the siting and design of new substations, or substation extensions, in order to mitigate the environmental effects of such developments. Whilst these rules are not enshrined in any form of planning policy they have been used internally at NGET for a substantial period as a guide to substation location. The Horlock Rules are summarised in Table 6.1.

Table 6.1 The Horlock Rules – siting and design of electrical substations

Overall system options and site selection

1 In the development of system options, including new substations, consideration must be given to environmental issues from the earliest stage to balance the technical benefits and capital cost requirements for new developments against the consequential environmental effects in order to keep adverse effects to a reasonably practicable minimum.

Amenity, cultural or scientific value of sites

2 The siting of new National Grid substations, sealing end compounds and line entries should as far as reasonably practicable seek to avoid altogether internationally and nationally designated areas of the highest amenity, cultural or scientific value by the overall planning of the system connections.

3 Areas of local amenity value, important existing habitats and landscape features including ancient woodland, historic hedgerows, surface and ground water sources and nature conservation areas should be protected as far as reasonably practicable.

Local context, land use and site planning

4 The siting of substations, extensions and associated proposals should take advantage of the screening provided by land form and existing features and the potential use of site layout and levels to keep intrusion into surrounding areas to a reasonably practicable minimum.

5 The proposals should keep the visual, noise and other environmental effects to a reasonably practicable minimum.



6 The land use effects of the proposal should be considered when planning the siting of substations or extensions.

Design

7 In the design of new substations or line entries, early consideration should be given to the options available for terminal towers, equipment, buildings and ancillary development appropriate to individual locations, seeking to keep effects to a reasonably practicable minimum.

6.4.22 In addition to the Horlock Rules, NGET assessed their options against specific technical criteria as presented in Table 6.2.

Table 6.2 National Grid Technical Criteria

National Grid Additional Assessment Criteria

Site Size The selected site needs to be able to accommodate the necessary infrastructure required to support the development.

Proximity to overhead lines

The NGET substation needs to be sited as closely as possible to the existing 400kV overhead lines running between Sizewell and Bramford, otherwise significant costs would be incurred in installing 400kV cables.

Proximity to existing

transmission tower locations

The connection to the overhead lines could be achieved by downleads from existing towers to gantries or sealing end compounds adjacent to the towers, or by the diversion of an overhead line to serve the substation. Additional towers, associated with a diversion, could increase visual impact in, or from, the Area of Outstanding Natural Beauty and also incur further outages.

Proximity to abnormal load access route

A designated and permanent abnormal load route is required to accommodate the transport of transformers to and from the site. Sizewell Gap is an existing designated abnormal load route which was constructed to provide access to the Sizewell power stations, additional costs and environmental impact could be incurred in constructing a new high specification load route.

Extent of outages required

It is preferable to select a site where minimal outages are incurred, particularly in the light of the obligation to maintain connections to the existing nuclear power stations. In order to avoid additional outages, there needs to be sufficient space for the construction to be no closer than 35m to a live overhead line.

Interconnectivity with GWF and existing circuits

In order to connect GWF into the existing circuits, there are benefits to locating the NGET substation close to the existing GGOWF circuits.

Clustering of infrastructure

Operational, access and security benefits could be achieved locating the NGET infrastructure adjacent to other infrastructure, i.e. GGOWF substation. Avoiding proliferation of infrastructure across the area could minimise visual and other environmental impacts.



6.5 GWF Compound

Defining the study area

6.5.1 For the option appraisal exercise undertaken by GWFL the study area was defined based on Sizewell as the location of the grid connection offer (granted by NGET), a preferred landfall location at Sizewell beach and the physical constraints present landward of that position. A physical constraint, in this context, is one that a substation cannot be located within, or a cable corridor could not extend beyond, i.e. it is not considered technically viable to site the substation equipment within these areas or to trench through or underneath these features. The physical constraints identified within this study are shown on Figure 6.5.





6.5.2 Sizewell A is owned by the Nuclear Decommissioning Authority (NDA). It has the benefit of a nuclear site licence under the Nuclear Installations Act 1965. This means that any activity on the nuclear site requires management control by the Site Licence Company (Magnox Ltd) and the Nuclear Installations Inspectorate. Discussions with the NDA, regarding the potential use of the Sizewell A site, indicated that the decommissioning programme for Sizewell A could not be accommodated within the GWF consenting and development programme. The decommissioning programme indicates that demolition activity on the Sizewell A site would continue up until at least 2016 (British Nuclear Group, 2005). This timeframe is based on the assumption that defuelling activities would begin in 2006; however, this did not actually begin until 2009, and as such the overall decommissioning programme would be expected to be delayed until 2019.

6.5.3 Whilst a proportion of the Sizewell A site will eventually become available during decommissioning, this is not expected to be available for new development until 2019 at the earliest. As an area of land sufficient for the GWF compound would be unlikely to be available within the timescales required, the Sizewell A site was treated as unavailable for the location of a GWF compound within the option appraisal exercise. EDF Energy and the owners of Sizewell B also commented that although the necessary land requirements associated with the potential new nuclear build project at Sizewell are not yet known, there is a strong requirement to maintain the possibility of using nuclear licensed land at Sizewell A wherever practicable. As such there would be a significant potential, even if decommissioning timescale constraints could be overcome, that EDF Energy would seek to re-acquire the land at Sizewell A for this purpose.

6.5.4 In addition to the question of timing, and EDF Energy's intentions for the site for potential nuclear-related uses, there were space constraints and safety considerations, which assisted in discounting Sizewell A.

6.5.5 A further site adjacent to Sizewell A, Coronation Wood, was also examined by GWFL to ascertain whether this could be suitable for locating the GWF compound, however EDF Energy indicated that this site may be affected by or required by the Sizewell C development. Coronation Wood was therefore not taken forward into the options appraisal study.

6.5.6 Once the limits of the study area were defined based on the physical constraints identified previously, ten potential GWF compound locations were identified that could physically accommodate the proposed GWF compound. For the purposes of the study it was assumed that an area of at least 1.5ha would be required. These sites are listed in Table 6.3.



6.5.7

Table 6.3 GWF compound site options

Option Location

1 Land north of Sizewell Gap Road, immediately west of Greater

Gabbard OWF substation

2 Land south of Sizewell Gap road, half way between Home Farm and

Halfway Cottages

3 Land immediately to the east of the junction between the B1122 and

Lover’s Lane

4 Land to the west of Sizewell B within Sizewell Marshes

5 Land to the south of the junction between Valley Road and Lover’s

Lane

6 Land south of Grimseys Lane, immediately east of Hawsells Farm

7 Land south of Grimseys Lane, immediately west of Hawsell’s Farm

8 Land to the east of Aldringham (approximately 300m east of

Aldringham House)

9 Land south east of Aldringham between the B1353 and Church Lane

10 Land immediately west of Thorpeness Common

6.5.8 A series of environmental constraints, such as designated sites and flood risk, were then identified. The physical and environmental constraints, together with the ten potential sites identified for the GWF compound are shown in Figure 6.6.

6.5.9 The ten GWF compound options were then appraised to identify any positive features and any potentially adverse environmental or technical impacts relating to the options. As part of this exercise a landscape and visual appraisal of each option was also undertaken. This was informed by desktop and field based assessment and included the use of computer generated models to identify the Zone of Theoretical Visibility (ZTV) for each option. The summary findings of the option appraisal exercise for the GWF compound are presented in Table 6.4. Full definitions of each of the criteria used in the assessment are set out in the Site Appraisal Study, which is included as an Appendix to the Consultation Report. The study also includes a full discussion regarding each of the options.





Table 6.4 Appraisal of long list of GWF compound site options

CONSTRAINTS CRITERIA OPTION

1 2 3 4 5 6 7 8 9 10

Nature conservation Proximity to international NC designation (Ramsar,

SPA or SAC) Amber = <0.5km, 350m adj. 2650m 1200m 930m 500m 900m 400m 450m 300m

Proximity to national NC designation (SSSI, NNR) Red = within, Amber = <0.2km, 250m adj. 680m 580m 500m 900m 400m 450m 220m

Hydrology and flood risk

Proximity to areas at risk from flooding (Zone 2) Red = within, Green = not within

Landscape

Site located within a designated landscape (AONB) Amber = within, Green = not

within

Development proposal broadly compatible with the

local landscape character

Amber = not compatible, Green

= compatible

Proximity to existing industrial landscape Amber = distant, clear = close,

Green = very close

Visual amenity

Consistently visible from primary vehicular routes

within 2km

Amber = consistently visible,

Green = not consistently visible

Consistently visible from PRoW (within 1km) Amber = consistently visible,

Green = not consistently visible

Visible from principal settlements Amber = visible, Green = not

visible

Visible from dwellings within 1km Amber = visible, Green = not

visible



Landscape & visual mitigation opportunities

Opportunity for sensitive cut and fill , Green = opportunity, Amber =

no opportunity

Opportunity to utilise the existing planting framework Green = opportunity, Amber =

no opportunity

Opportunity for additional planting Green = opportunity, Amber =

no opportunity

Archaeology & cultural heritage

Proximity to Scheduled Monuments and Listed

Buildings

Amber = <0.5km, Clear = 0.5-

1km, Green = >1km

2500

m 2150m 320m 1800m 1530m 1350m 900m 750m 270m 1600m

Traffic & access

Highway access Amber = poor, Clear =

acceptable, Green = good

Distance & constraints to connection point

Proximity to existing NGET Infrastructure (Sizewell PS

or 400kV OHL)

Amber = >1km, Clear = 0.5-1km,

Green = <0.5km 160m 120m 2300m 750m 1100m 170m 200m 230m 830m 1650m

Physical/technical constraints between connection

point & option (e.g. roads, settlements, industry,

floodplain)

Amber = significant constraints,

Clear = acceptable constraints,

Green = none

Environmental constraints between connection point &

option (e.g. nature conservation designations, habitats)



Green = none

Distance & constraints to landfall point

Proximity to landfall point/area Amber = >2km, Clear = 1-2km,

Green = <1km 900m 880m 3100m 1800m 2100m 2000m 2700m 2800m 3300m 2250m

Physical/technical constraints between option location

& landfall (e.g. roads, settlements, industry, floodplain)



Green = none

Environmental constraints between option location &

landfall (e.g. nature conservation designations,





habitats) Green = none

Appraisal

Appraisal result

Y = carry forward to Step 9, N =

discount Y Y N N Y N N N N N

Key

Showstopper

Adverse option attribute

Neutral option attribute

Positive option attribute [note 1]

Notes

1. Positive option attribute is with respect to option selection process, does not imply a beneficial environmental impact

2. Distances approximate and taken from centre point of option to site boundary of designation/feature



6.5.10 As shown in Table 6.4 Option 4 was discounted because it is located within a nationally designated site and is within Flood Zone 2.

6.5.11 Table 6.4 shows that landscape and visual impacts were a major constraint for most of the options being considered and that there were potential landscape and visual impacts both within and outside the boundary of the Suffolk Coast and Heaths AONB. Landscape impacts identified included the effects of the GWF compound on open views; the limited existing screening that could mitigate visual impacts; proximity of the options to Leiston or Aldringham; and whether the option was located in the AONB.

6.5.12 After reviewing the potential GWF compound locations against the environmental constraints it was concluded that Options 3, 4, 6, 7, 8, 9 and 10 were unsuitable for further consideration and that Options 1, 2 and 5 were considered as potential locations.

Identifying a preferred option

6.5.13 GWF Option 1 is located close to the existing Sizewell Power Stations and adjacent to the GGOWF substation. Option 2, by way of contrast, has much less of a visual connection to the Sizewell Power Station or GGOWF infrastructure resulting in a greater proliferation of industrial development within the protected landscape and more noticeable alteration to the intrinsic character of the AONB. Option 5, although close to the Eastlands Road Industrial Estate, would extend development beyond the existing and well defined urban boundary.

6.5.14 The scope for effective and sensitive mitigation is more limited for Options 2 and 5 due to their location in more exposed and open landscapes and proximity to residential properties. Whilst screening planting would moderate the visual impact of development in the medium to long-term, it is likely to appear artificial and contrived given the character of the surrounding landscape.

6.5.15 Through consideration of Horlock Rule 4 “The siting of substations, extensions and associated proposals should take advantage of the screening provided by land form and existing features and the potential use of site layout and levels to keep intrusion into surrounding areas to a reasonably practicable minimum” and following expert assessment of each option’s ZTV, it becomes clear that although Options 1 and 2 sit within the AONB they have a much greater potential for mitigation given the existing screening effects of the adjacent woodland blocks (Option 1) and the topography of the land (Options 1 and 2).

6.5.16 Further to the GWF site options appraisal and as part of the non-statutory consultation process a Community Consultation exercise was undertaken by GWFL. This consultation began in November 2010 with a public exhibition in Leiston and concluded in January 2011. GWF Options 1, 2 and 5 were presented as the shortlisted GWF options and all attendees were invited to submit a feedback form on their preferred option. The overriding majority of respondents indicated that of the three options presented, their preference



was for Option 1 to be selected as the location for the GWF onshore substation. A report detailing these findings is available on the GWF website (www.galloperwindfarm.com).

6.5.17 Various meetings and discussions with SCDC and SCC were held in relation

to the potential sites for the GWF compound and the need to strike the correct balance between AONB considerations and the opportunities for mitigation, and other matters. GWFL carried out a site visit with SCDC and SCC officers to each of the three sites which were the subject of the public consultation. At the end of a long process, SCDC and SCC officers expressed a clear preference for Option 1 in the light of the various relevant planning considerations. Option 1 was therefore identified as the preferred option for the GWF compound based on the responses to the consultation and the following landscape and visual considerations:

The site is located within a landscape which is partly defined by its industrial setting;

The site is largely screened in views from nearby settlements and detached dwellings;

Cumulative landscape and visual effects are likely to be minor due to the site’s proximity to the existing GGOWF substation;

It is the only site where there is considerable scope for effective perimeter planting in conjunction with sensitive earth modelling in order to mitigate against landscape and visual effects, in a manner sympathetic to the existing landform and vegetation framework; and

The proximity of the site to existing woodland would allow greater assimilation of the scheme into the existing landscape framework.

6.6 Transmission Compound

6.6.1 NGET undertook a separate option appraisal exercise during 2011, to consider options for the transmission compound and associated infrastructure. The transmission compound would involve a smaller land take than the GWF compound. Table 6.5 presents the transmission compound alternative site options that were assessed, together with a summary of whether each site was short listed to be presented to the public for comment, or discounted. The full report (3G Communications, 2011) is included in n Appendix to the Consultation Report.



Table 6.5 Long list of alternative NGET substation options

Option Location Summary of status

NG A The site of the existing NGET Sizewell A

substation.

Considered suitable due to

existing NGET land interests in

the site. It is located close to the

existing transmission towers and

overhead lines

Short listed for public

consultation

NG B Coronation Wood, immediately to the west

of the Sizewell A land, adjacent to

transmission towers and overhead lines.

EDF Energy indicated that this

land may be affected or required

by the Sizewell C development.

Discounted

NG C Pillbox field, to the south of Sizewell A but

north of Sizewell Gap. Close to existing

OHL.

EDF Energy indicated that this

land may be affected or required

by the Sizewell C Development.

Discounted

NG D South of Sizewell Gap and east of Sizewell

Hall access road.

Constrained by GGOWF cabling,

prominent location in AONB,

requirement for long cable route.

Discounted

NG E To the south of Sizewell Gap and

immediately west of Home Farm.

Close to existing OHL, but

constrained by existing GGOWF

cable corridor south of Sizewell

Gap.

Parked due to prominent location

and proximity to amenities; but to

be explored further if no other

option is acceptable.




NG F In arable land immediately south east of

Sizewell Wents

Close to the existing GGOWF

substation infrastructure, but

constrained by existing cabling

and only achievable through

diverting OHL incurring outages

and associated additional

infrastructure in AONB.

Discounted

NG G

(GWF

Option 2)

To the south of Sizewell Gap and

immediately adjacent to OHL and potential

connection.

Reasonably close to GGOWF

substation.

Parked due to proximity

advantages but conflicting

disadvantage of planning history

and landscape & visual issues.

NG H North of Sizewell Gap close to OHL towers

south west of Sizewell Wents.

Close to OHL towers and existing

GGOWF substation

Shortlisted for Public

Consultation

NG I

(GWF

Option 1)

Site immediately to the west and adjacent to

existing substation and close to potential

connection point. Advantage of screening

potential and existing woodland.

Shortlisted for Public

Consultation

NG J East of Lovers Lane and north of Sizewell

Gap with potential for screening.

Significant cable runs required to

connect to OHL tower and

Leiston A substation.

Discounted

NG K Area south of Halfway Cottages and

Sizewell Gap, close to existing OHL.

Distance from abnormal load

access route and c1km cable

route required to connect back to

Leiston A, routed to avoid SPA

and SSSI.

Discounted




NG L

(GWF

options

6,7 and

8)

Area south of Leiston on route of OHL,

outside AONB or other designated sites.

Distance from abnormal access

road, c1.5km cable route

required to connect back to

Leiston A substation.

Discounted

NG M

(GWF

option 5)

Site on the western edge of Leiston adjacent

to industrial estate and outside AONB.

Distance from existing substation

requires approximately 1km

cable to connect to OHL.

Discounted

NG N Hill Wood very close to Sizewell power

station complex.

Impact on screening function for

power stations.

Discounted.

NG O South east of Halfway Cottages. Area in SPA in AONB.

Discounted.

6.6.2 The three short listed options were presented at a public exhibition held in

Leiston in March 2011, and attendees were invited to comment on their preferred location. The majority of respondents favoured options NG A (the existing NGET Sizewell A substation) and NG I (the site immediately to the west of them existing GGOWF substation) as the preferred locations for the transmission compound and associated infrastructure.

6.6.3 Suffolk Wildlife Trust submitted a consultation response to NGET stating that NG A (Sizewell A option) presents significant adverse impacts to the Sizewell Marshes SSSI through encroachment of the connection infrastructure into the SSSI, and the need for cabling across the SSSI to provide the necessary connection to the Leiston A substation.

6.6.4 Further discussions with EDF Energy, regarding the future use of the Sizewell A site, concluded that avoiding the use of the Sizewell A land represents the least disruption to both the continuing operation of Sizewell B and the proposals for Sizewell C, and that EDF Energy would seek to maintain the possibility of using existing nuclear site licensed land at Sizewell A where practical.

6.6.5 The need to avoid the impact on the SSSI and the points raised by EDF Energy regarding minimising disruption and maintaining nuclear licensed land for nuclear purposes, therefore, led to the NG A (Sizewell A) site being discounted.



6.6.6 Of the remaining two options (NG I and NG H), the site next to the proposed GWF compound (NG I) was concluded to be preferable to that next to Sizewell Gap (NG H) because it minimises the cumulative impact and offers better opportunities for screening.

6.6.7 Various meetings and discussions with SCDC and SCC were held in relation to the potential sites for NGET’s compound and the need to strike the correct balance between AONB considerations and the opportunities for mitigation, and other matters. SCDC and SCC officers understood why NGA was not a possible location and expressed a clear preference for Option 1 in the light of the various relevant planning considerations and with the aim of keeping all of the GWF associated infrastructure in the same location. This is consistent with the views expressed in the NGET consultation, that NG I is the preferred site after Sizewell A (NG A).

6.7 Connection to the national electricity transmission system

6.7.1 To connect the substation to the national electricity transmission system NGET considered both overhead line and cable connections to existing underground transmission cables. A 400kV connection is required to connect the transmission compound to the 400kV overhead lines. A 132kV cable connection between the transmission compound and the existing Leiston A substation (the transmission compound element of the GGOWF substation) is also required to ensure system security.

6.7.2 Two double circuit 400kV overhead lines pass close to the selected transmission compound with the closest transmission towers (pylons) located to the east of the Leiston A substation. A direct overhead line connection from these towers to the proposed GWF transmission compound was discounted as it would not be technically possible due to the designs of the existing tower.

6.7.3 Although possible to change the existing overhead line route between other towers and connecting directly to the proposed transmission compound via two tee-off circuits this would require the construction of about 1.4km of new overhead line which would be closer to Halfway Cottages than the existing line. It would involve construction work within a SSSI and SPA and the landscape and visual impact of such a proposal, in the AONB, would be greater than that of the existing line.

6.7.4 Other alternatives could only be achieved with extensive temporary bypass arrangements which would pass through Sizewell Marshes SSSI or would require the proposed GWF transmission compound to be located to the south of Sizewell Gap. This position is not favoured by the local community, could involve construction work within a SSSI and SPA and would have greater landscape and visual impacts. In addition, because of the need to maintain security of connection to the nuclear power stations, the availability of outages is very restricted and it is unlikely to be possible to derive a construction programme for an overhead line diversion which would allow the contracted connection date for GWF to be achieved.



6.7.5 NGET therefore selected to connect the GWF transmission compound to the existing 400kV overhead lines via the closest towers located to the east of the Leiston A, This will be achieved by converting the existing towers into tee-off towers and installing downleads into sealing end compounds at each tower, connecting to Leiston B via underground cables. For electrical proximity and safety reasons the tee-off circuits must be from the two outboard circuits at each tower.

6.7.6 Two joints for each circuit are required between the new and proposed 132kV cables to connect the transmission compound to the existing 132kV circuits between Leiston A and Sizewell B to ensure security of supply. The first jointing area is located immediately to the south of the existing Leiston A substation. The second location was chosen so as to be in relatively close proximity to the GWF transmission compound.

6.8 Cable Corridors

6.8.1 Given the relatively short distance between the chosen locations for the cable landfall, the GWF substation and the connections to the transmission system there were few realistic alternatives for the locations of the cable corridors. This section considers the reasoning behind the selection of the main cable corridors included in the application: the GWF export cable/s, the 132kV transmission cables and the 400kV transmission cables.

6.8.2 The selected locations for the GWF export cable corridor, the 132kV transmission cable corridor and the 400kV transmission cable corridor are shown in Figure 6.8.





6.8.3 The chosen GWF export cable corridor lies alongside the existing GGOWF cable corridor for much of its length. Keeping the GGOWF and GWF cable infrastructure together will help to reduce the effect on existing land uses, particularly the arable fields to the south of Sizewell Gap. The GWF export cable corridor crosses Sizewell Gap to the west of the GGOWF cable crossing. This allows the GWF export cable corridor to be located close to the hedgeline south of Sizewell Gap. After crossing Sizewell Gap the cable corridor is routed in a northward direction to the GWF compound, thereby minimising the length of cable corridor required. This route also allows the GWF cable corridor can avoid the area to the south of the GGOWF substation where a number of electric cables are already located and where other GWF electric cables need to be located.

6.8.4 The 400kV transmission cable corridor needs to link the GWF transmission compound to the identified preferred 400kV connection identified in Section 6.7 - the two overhead line towers to the east of the existing GGOWF substation. The presence of existing cables to the south of Leiston A constrains the routeing of the 400kV cable connection between the GWF transmission compound and the towers. Crossing these cables is undesirable because of engineering and technical constraints and an unacceptable degree of risk of damage to third party infrastructure and generating capacity and would pose longer term maintenance difficulties.

6.8.5 An alternative route to the north of Leiston A substation was therefore taken forward. This would mean routeing the cable corridor through Sizewell Wents woodland and require trees to be removed from and adjacent to the cable easement to protect the cables from physical damage and changes to resistivity.

6.8.6 A route running north from the GWF transmission compound and then following the bridleway to the east was considered. However this would result in significant tree loss adjacent to the bridleway and would require closure or diversion of the bridleway during construction. The latter was not considered to be practical given the other construction works being undertaken in the area and the constraint of the SSSI. This option was therefore rejected. The route selected for the 400kV cable corridor was one which runs close to the northern boundary of the GGOWF compound before entering the field to the east of the compound. Although this would also result in tree losses these would be located further from the bridleway and would not result in significant disruption to users of the bridleway. This route also has the advantage of being located further from Sizewell Marshes SSSI.

6.8.7 For the 132kV cable corridor, options to the north or south of Leiston A were considered. A northerly cable route would be significantly longer than one to the south as it would have to pass around the periphery of the GWF transmission compound and the GGOWF compound. It would also need to be routed to the north and east of the two transmission towers to avoid crossing the 400kV cable route. The presence of the 400kV cables would



also lead to congestion and working difficulties to the north of the GGOWF compound, and would lead to a cable corridor in close proximity to Sizewell Marshes SSSI. A southerly cable route was therefore chosen as, although this would involve crossing existing 132kV cables to the south of Leiston A, this could be achieved without outages and the risk to third party assets is considered to be acceptable, given the reduced scale of construction compared to a 400kV crossing.

6.8.8 The selected 132kV transmission cable corridor commences in the transmission compound and loops south and then east around Sizewell Wents then continues in an easterly direction until it meets the existing 132kV cables which run from the GGOWF transmission compound to Sizewell B Nuclear Power Station. Routing this corridor around the existing woodland has meant that fewer trees will need to be felled than if the corridor was routed through Sizewell Wents. The width of the cable corridor immediately to the south of the transmission compound has been reduced to 15m (from 19m) for a short distance to avoid felling trees located close to the cable corridor in this area. An alternative route was considered for this corridor which would have located it alongside the proposed substation access road. However this would result in additional tree loss in the centre of Sizewell Wents.

6.9 References

3G Communications (2011) Galloper Wind Farm Connection National Grid substation - consultation: public data report British Nuclear Group (2005) Sizewell A Nuclear Power Station Environmental Statement Galloper Wind Farm Ltd (2011) Site Appraisal Study: Assessment of Potential Substation Locations Infrastructure Planning Commission (2010) Scoping Opinion: Proposed Galloper Wind Farm Project National Grid (2006). Guidelines on Substation Siting and Design (The Horlock Rules) SSE Renewables and RWE Npower Renewables Limited (2010) Galloper Wind Farm Project Scoping Study

Documents

Galloper Wind Farm Project · Final Report Chapter 6 – Page 1 October 2011 6 SITE SELECTION AND ALTERNATIVES 6.1 Introduction 6.1.1 This Chapter of the Environmental Statement (ES)