JUNE 2011 Bramford to Twinstead Tee Connection Project Selection of Preferred Corridor CONTENTS PAGE No. 1 INTRODUCTION 1 2 BACKGROUND TO THE PROPOSAL 2 3 ROUTE CORRIDORS 14 4 FACTORS EMPLOYED IN EVALUATING CORRIDORS 17 5 OTHER FACTORS CONSIDERED IN THE EVALUATION OF ROUTE CORRIDORS 23 6 ELECTRICITY ACT - SECTION 9 OBLIGATIONS 27 7 NATIONAL AND LOCAL POLICY CONTEXT 34 8 NATIONAL GRID POLICIES 54 9 STAGE 1 CONSULTATION REPRESENTATIONS 59 10 LANDSCAPE AND VIEWS 72 11 HERITAGE 98 12 ECOLOGY/BIODIVERSITY 106 13 LAND USE AND SOCIO-ECONOMIC FACTORS 112 14 ENGINEERING - BUILDABILITY/DELIVERABILITY 120 15 AVIATION/DEFENCE INTERESTS 125 16 CLIMATE CHANGE RESILIENCE AND FLOOD RISK 127 17 MITIGATION 130 18 COMPARISON OF ROUTE CORRIDORS 134 19 CONCLUSIONS 146 20 NEXT STEPS 147 Appendices Appendix 1 : Abbreviations Figures 1 Route Corridors Bramford to Twinstead Tee Connection Project Selection of Preferred Corridor 1 INTRODUCTION Purpose of report 1.1 This report outlines the selection of a preferred corridor for a proposed 400kV overhead transmission line connection between Bramford substation (near Ipswich, Suffolk) and Twinstead Tee (near Sudbury, Suffolk). It demonstrates how statutory duties, policy considerations, technical and environmental issues and consultation feedback have shaped and influenced the selection of the preferred corridor. 1.2 The report is structured as follows : • Chapter 2 - explains the background to the proposal, including the need for the connection. It also outlines how potential reinforcement alternatives were identified and assessed and reports responses to some of those alternatives, reaching a conclusion on the preferred form of connection; • Chapter 3 - describes the potential corridors that were evaluated. These formed the basis for the Stage 1 Consultation, which is reviewed in more detail in Chapter 9; • Chapter 4 - identifies those factors which have been taken into account in the route corridor selection process; • Chapter 5 - discusses other factors which were considered not to affect corridor selection; • Chapters 6 to 16 - assess the potential corridors against each of the factors in Chapter 4 and note related consultation representations; • Chapter 17 - discusses potential mitigation measures, particularly the use of underground cables; • Chapter 18 - contains an overview of the relative merits of the corridors and provides a basis for selecting a preferred corridor, with reference to consultation representations which have influenced that selection; • Chapter 19 - sets out the conclusions of the report; • Chapter 20 - outlines the next steps, including how a detailed connection design will be identified and environmental impact assessment and 1 Bramford to Twinstead Tee Connection Project Selection of Preferred Corridor further consultations undertaken, leading to the preparation and submission of an application for development consent to the Infrastructure Planning Commission (IPC) or its successor body. 1.3 Reference is made to a number of separate but related project-specific reports which can be read alongside this Selection of Preferred Connection report – the Project Need Case 1, the Strategic Optioneering Report 2, the Review of Strategic Options report 3, the Route Corridor Study Report 4 and the Stage 1 Feedback Report 5. 2 BACKGROUND TO THE PROPOSAL National Grid 2.1 National Grid is the operator of the high-voltage transmission system for the whole of Great Britain and the owner of the high voltage transmission network in England and Wales 6. 2.2 National Grid’s transmission system in England and Wales consists of approximately 7,200km of overhead lines and a further 700km of underground cabling, operating at 400kV and 275kV. 400kV lines are at the higher voltage giving them a higher power carrying capability, while 275kV lines generally represent the older parts of the network which were established prior to the 400kV transmission system. 2.3 The overhead lines and cables connect around 340 substations to form a highly interconnected network. The substations provide points of connection for around 80 power stations and for connections to the local distribution networks, which operate at voltages from 132kV down to 240V (at which voltage, the power is distributed to domestic consumers). The distribution networks are 1 National Grid : Bramford to Twinstead Connection : Need Case for the East Anglia Region : June 2011 2 National Grid : Bramford to Twinstead 400kV Overhead Line Project Strategic Optioneering Report : October 2009 3 National Grid : Bramford to Twinstead Tee Connection East Anglia : Review of Strategic Options : June 2011 4 TEP : Bramford to Twinstead 400kV overhead line project : Route Corridor Study for Public Consultation : October 2009 5 National Grid : Bramford to Twinstead Tee Connection Project : Feedback Report on Stage 1 Consultation : June 2011 6 The transmission network in Scotland is owned by Scottish Power Transmission Limited in southern and central Scotland and by Scottish Hydro-Electric Transmission Limited in the north of Scotland. 2 Bramford to Twinstead Tee Connection Project Selection of Preferred Corridor owned by Distribution Network Operators (DNOs), including UK Power Networks (hereafter referred to as UKPN) in East Anglia. 2.4 National Grid has duties placed upon it by the Electricity Act 1989 7 ('the Electricity Act') and operates under the terms of its transmission licence. Those duties and terms of particular relevance to the development of the proposed connection described in this report are set out below. Duties under the Electricity Act 1989 2.5 Under Section 9(2) of the Electricity Act, National Grid has a duty: • to develop and maintain an efficient, co-ordinated and economical system of electricity transmission; and • to facilitate competition in the supply and generation of electricity. 2.6 Section 38 and Schedule 9 of the Electricity Act require National Grid, when formulating proposals for new lines and other works, to: • “… have regard to the desirability of preserving natural beauty, of conserving flora, fauna, and geological or physiographical features of special interest and of protecting sites, buildings and objects of architectural, historic or archaeological interest; and shall do what [it] reasonably can to mitigate any effect which the proposals would have on the natural beauty of the countryside or on any such flora, fauna, features, sites, buildings or objects ”. 2.7 In its Stakeholder, Community and Amenity policy 8, National Grid sets out how the company will meet the duty placed upon it by the aforementioned legislation. This includes : • only seeking to build new lines and substations where the existing transmission infrastructure cannot be upgraded to meet transmission security standards; 7 Electricity Act : 1989 c29 8 National Grid plc : National Grid's commitments when undertaking works in the UK - our Stakeholder, Community and Amenity Policy : February 2010 3 Bramford to Twinstead Tee Connection Project Selection of Preferred Corridor • seeking to avoid nationally and internationally designated areas where new infrastructure is required; and • minimising the effects of new infrastructure on other sites valued for their amenity. 2.8 The Stakeholder, Community and Amenity Policy also commits to the application of best practice methods, to assess the environmental impacts of proposals and identify appropriate mitigation measures, and to promoting effective stakeholder and community engagement. Transmission licence 2.9 Licence Condition C8 (Requirement to offer terms) sets out obligations on National Grid regarding provision of offers to provide connections to the transmission system. In summary, where any person applies for a connection, National Grid shall offer to enter into an agreement(s) 9 to connect, or to modify an existing connection, to the transmission system and the offer shall make detailed provision regarding: • the carrying out of works required to connect to the transmission system; • the carrying out of works (if any) in connection with the extension or reinforcement of the transmission system; and • the date by when any works required to permit access to the transmission system (including any works to reinforce or extend the transmission system) shall be completed. 2.10 Licence Condition C17 (Transmission system security standard and quality of service) requires National Grid to “ at all times: plan, develop and operate the licensee's transmission system … in accordance with the National Electricity Transmission System Security and Quality of Supply Standard version 2.1 ” (NETS SQSS) 10 . 2.11 The NETS SQSS is a document that defines criteria which specify the robustness of the transmission system, in terms of the faults, and combinations of faults, 9 Paragraph 6 of Licence Condition C8 sets out exceptions where National Grid is not obliged to make an offer e.g. where to do so would put it in breach of certain other contracts or regulations. 10 NETS Security and Quality of Supply Standard Issue 2.1 - 07 March 2011 4 Bramford to Twinstead Tee Connection Project Selection of Preferred Corridor that it must be able to withstand without any interruption of supplies, and the maximum interruption to supplies which is permitted for certain more onerous combinations of faults. The NETS SQSS is subject to updates through industry and regulatory working groups, with this periodic review approved by the industry regulator, Ofgem. The Need for the Connection 2.12 The need for the connection is set out in