Committee Report NSC

6.2
 
North Somerset Council

 

REPORT TO THE Planning & Regulatory Committee

 

Date of Meeting:  25 November 2009

 

Subject of Report: National Grid Overhead Line Connection to Hinkley Point

 

Town or parish:  Banwell, Sandford, Loxton , Christon Winscombe, Yatton, Congresbury, Weston-super-Mare, Puxton, Churchill, Kenn, Tickenham, Nailsea, backwell Wraxall, Clapton-IN-GORDANO, portbury, portishead, Easton-in-gordano

 

Officer/Member presenting: Graham Quick (Local Planning Team LEADER)

 

Key Decision:   NO

 

RECOMMENDATIONS

 

That National Grid is recommended to fully investigate the option of routing the lines along the seabed of the Bristol Channel;

 

Subject to the outcome of the above, the Council’s preferred option is Option 1A replacing the current 132KV line through the District with a 400 KV line) with the under grounding of the overhead line route through the Mendip Hills Area of Outstanding Natural Beauty;

 

National Grid is requested to continually involve the Council in the process of determining the exact alignment of the overhead lines and siting of new pylons.

 

1.                Summary of Report

 

The report sets out the rationale behind the need for a new 400 KV overhead line through the district and examines the three options put forward by National Grid

 

2.                Policy

 

There is no Council policy on the siting of overhead electricity lines although the North Somerset Replacement Local Plan contains policies that seek to protect residents from harmful environmental effects and also protect the landscape from inappropriate development


 

3.                Details

 

Justification for the new Overhead Line

 

National Grid has a statutory obligation to connect new electricity generators to its system. National Grid have received an application from British Energy Generation Limited (now part of EDF Energy) to connect a 3600MW nuclear power station at Hinkley Point by September 2017.

 

The power station would comprise two 1800MW European Pressurised water reactors (EPR). It would be one of the largest single generators connected to the National Grid system and, as a result, extensive reinforcement and upgrading to the network in the region is needed to accommodate the extra power and ensure system security. This will include replacing wires on existing overhead line routes and upgrading some substations.

 

In addition to this, a new 400,000 volt overhead line linking the Bridgwater and Seabank substations is also needed to accommodate the new power. This route has been identified as the most efficient and economic route to facilitate the connection as well as being essential to help connect other power generation facilities which will help meet Government renewable targets by 2020. Depending upon the final route, the overhead line could be up to 37 miles long.

 

Planning Act 2008

 

The new Planning Act 2008 recognises that overhead electricity lines of 132,000 volts and above are nationally significant infrastructure projects and from 1 October 2009 a new, independent body called the Infrastructure Planning Commission (or IPC), will be responsible for making decisions on applications for such projects. In effect the Council is a consultee along with other local and town councils.

 

In most circumstances, cases will be decided within a year from application. Where necessary, hearings into applications will be held.  Applications to the IPC must accord with National Policy Statements (NPSs), drafted by the Government, which cover different areas, such as transport and energy.

 

Six NPSs are being produced for the energy sector, including ones for electricity networks and nuclear power.  Under this planning process, National Grid will be required to apply to the IPC for an order granting ‘development consent’ for new 400,000 volt overhead lines and any ‘associated development’. The application must also identify all approvals required to allow the development to proceed. The application must be accompanied by a:

 

·        Consultation report and responses to the pre-application consultation.

·        Environmental Statement, which details the impact of the proposals on areas such as ecology, landscape, cultural heritage, land use and noise.

·        Proposed draft order and explanatory memorandum.

·        Statement of reasons if land needs to be compulsorily purchased.

 

What are the factors determining the best route?

 

Guidelines for the routeing of new overhead lines were originally formulated by the Central Electricity Generating Board, a predecessor to National Grid. These guidelines are known as the ‘Holford Rules’. They have subsequently been reviewed and supplemented by National Grid and are used as the basis to routeing new overhead lines.  The guidelines set out the principles to be applied in the routeing of new overhead lines. The selection of any new route will be a balance of all the various factors or constraints that have to be taken into account.

 

In selecting an overhead line route, the guidelines seek to reduce the visual effect in terms of the number of people affected and the degree to which they are affected. The nature and topography of the landscape is considered and any statutory protection afforded to an area is also taken into account.

 

They seek to avoid the following areas, which are nationally or internationally designated for their landscape, wildlife or cultural significance: National Parks; Areas of Outstanding Natural Beauty; Sites of Special Scientific Interest including Special Protection Areas, Special Areas of Conservation and Ramsar sites; National Nature Reserves; Heritage Coasts; World Heritage Sites; and scheduled ancient monuments.

 

The selected overhead line route will typically seek to avoid crossing the highest contours, where pylons would generally be the most prominent, and will take account of the quality of the landscape and its ability to accommodate an overhead line. The guidelines seek to:

 

 

Route Corridor Options

 

Consultants have been commissioned by National Grid to undertake a route corridor study (RCS) to identify potential route corridors between Bridgwater and Seabank substations.  Route corridors are areas of land in which an alignment can be identified for the new 400kV (400,000 volts) overhead line.

 

The study area for the RCS extends from the existing overhead lines northwest of Bridgwater to the existing National Grid 400kV electricity substation at Seabank, north of Bristol.  The study area falls within the administrative control of the following district and county authorities:

 

 

Key constraints identified within the study area that influence potential route corridors between Bridgwater and Seabank include:

 

 

Two potential route corridors have been identified for the required connection. 

 

Corridor 1 - Route along the Existing 132kV Line Bridgwater to Seabank

 

Route corridor 1 would involve the adoption of the route of the existing 132kV overhead line which travels through the study area in a broadly north-south direction between existing substations at Bridgwater and Seabank.  The existing 132kV overhead line is supported on lattice steel towers (pylons) approximately 27m high.

 

Two potential options have been identified within this corridor.( see attached plan)

 

Option 1A involves the removal of the existing overhead line and the erection of a new 400kV overhead line in its place.  The proposed overhead line would use towers of a new design, which are likely to be approximately 47m high although extensions or reductions may be required in places depending on the land topography.    This option would require a new 400/132kV grid supply point (GSP) substation in the vicinity of Churchill in North Somerset and a new 4km length of 400kV overhead line to connect this with the transmission network.  It has been assumed that a new 400kV overhead line would be built closely along the existing alignment to minimise the scale of change.

 

Option 1B involves the construction of a new 400kV overhead line parallel to the existing 132kV line.  The 132kV overhead line would not be removed.  As for Option 1A the proposed overhead line would use towers of the new design.  The closest technically achievable distance for paralleling is 50-70m from the existing 132kV overhead line.  However, this close alignment may be difficult to achieve along the full length of the route due to environmental constraints and the new 400kV line would need to be offset from a close parallel route in some places.

 

Corridor 2 – New 400kV Overhead Line Corridor

 

Route corridor 2 considers the construction of a new 400kV overhead line in a broadly north-south direction between Bridgwater and Seabank substations separate as far as possible from existing overhead lines.  This separation is difficult to achieve along the full length of the route due to environmental constraints such as the Mendip Hills AONB, Tickenham Ridge and Avonmouth.  As a result the corridor parallels the existing 132kV overhead line in some places resulting in two closely aligned overhead lines in the landscape. 

 

As for Corridor 1, the proposed overhead line would use towers of a new design approximately 47m high i.e. 20 metres higher than the existing pylons

 

Conclusions

 

All of the route corridor options transverse the Mendip Hills AONB in the Loxton/Christon/Winscombe area. Although National Grid will consider every case for undergrounding a power line on its merits, they do acknowledge a special concern for the protection of important landscape features in nationally or internationally designated areas of amenity value such as National Parks, Areas of Outstanding Natural Beauty, Heritage Coasts and World Heritage Sites.

 

Given the overall increase in height of the pylons (whatever route corridor option is chosen) then it is justified for the routing through the Mendip Hills AONB to be underground. In addition National Grid should also fully investigate and cost the option of routing the lines on the sea bed of the Bristol Channel. Although no doubt a costlier option it is one that has not been explored, but which would totally reduce any environmental impact from existing and proposed overhead lines

 

Subject to the above comments it is considered that Option 1A should be supported for the following reasons:

 

(i)      It avoids running close to some settlements and it would for the most part be much less intrusive than the alternative options of parallel line development or an entirely new route.  Route Corridor 2 for example would involve the construction of new pylons and overhead lines in the important green buffer between Nailsea and Backwell and also Nailsea and Wraxall.

 

(ii)     It would not involve a proliferation of overhead lines or pylons that would occur if Option 1B or Route Corridor 2 was chosen.

 

(iii)    It will follow broadly the line of the existing 132 KV line and although the pylons will be taller there is already a landscape impact along that corridor from the existing lines.

 

(iv)    Route Corridor 2 could potentially affect the SSSI to the west of Yatton and north east of Yatton.   

 

Once the route corridor is chosen it is imperative that the Council are continually involved in the decision making process on the exact alignment of overhead lines and siting of new pylons. This will enable the important local archaeological, ecology and landscape implications to be considered in the drawing up of a full Environmental Impact Assessment.

 

4.                Consultation

 

The Planning Act puts a stringent duty on National Grid to consult interested parties, including the public, local authorities and statutory bodies. If the IPC judges that a developer has carried out insufficient consultation, the application will not be accepted for consideration.

 

Before developers can consult the public, they must develop a Statement of Community Consultation (SOCC) which sets out how the developer will seek views. National Grid must submit a consultation report to the IPC, outlining how consultation was carried out and recording responses from consultees. National Grid is committed to seeking the views of all interested parties and will be carrying out a wide-ranging public consultation programme. National Grid gave a presentation to an all member briefing on September 15th.

 

There are two main consultation stages:

 

Stage 1 (Current Stage)

National Grid will invite the views of local communities and interested parties in the the vicinity of the proposed works about the route corridor options (stretches of land in which an overhead line could be sited)

 

Stage 2

National Grid will have to show how the views of the local community have been taken into account in deciding the preferred option. They will then develop route alignments for the proposed overhead line within the preferred route corridor and carry out further consultations on the more precise alignment options.  

 

The provisional timetable is:

 

October to December 2009

 

Late January to March 2010

 

March 2010 – Spring 2011

 

Summer 2011

 

5.                Financial Implications

 

At this stage there are no financial implications for the Council.

 

6.                RISK MANAGEMENT

 

Any delay in agreeing a preferred route corridor could result in a consequential delay for National Grid in submitting details to the Infrastructure Planning Commission.

 

7.                Equality Implications

 

No equality implications.

 

8.                Corporate Implications

 

At this stage the exact siting of new pylons is not known and therefore any implications for the Council’s land and buildings is unknown.

 

9.                Options considered

National Grid have put forward three options for consideration.

 

Author

 

Graham Quick Local Planning Team Leader 01934 624177

 

Background Papers

 

Statement of Community Consultation

Copy of the Route Corridor Study

Project Summary Information

National Grid Stakeholder, Community and Amenity Policy