Proposed Gills Bay 132kV / 33kV Substation

Scottish Hydro Electric Transmission Limited

SSE Power Distribution, part of SSE plc, owns and maintains two electricity networks in the north of Scotland - the electricity transmission network and the electricity distribution network.

In Scotland, SSE Power Distribution comprises two businesses:

Scottish Hydro Electric Power Distribution PLC (SHEPD) which operates the high and low voltage electricity network that distributes electricity to around 700,000 customers in northern mainland Scotland and the Scottish Islands.

and

Scottish Hydro Electric Transmission Limited (SHETL) which owns and maintains the 132kV and 275kV electricity transmission network in the north of Scotland, in some of the UK's most challenging terrain.

One of our principles of responsibility is to ensure the communities which we serve have a safe and reliable supply of electricity, and that we ensure we do everything we can to restore supplies as quickly as possible following interruptions.

Scottish Hydro Electric Transmission Limited Electricity networks provide an essential physical link between electricity generators and electricity users. As such, the owners of networks have statutory obligations including ensuring that they are able to provide an economic and efficient service to generators who wish to connect onto their network.

Electricity transmission businesses like SHETL are natural regional monopolies. As a result, they are regulated by the Gas and Electricity Markets Authority (Ofgem) through a ‘price control’. Amongst other things, this determines the framework for the capital investment they are able to spend in maintaining and upgrading the networks.

We own and operate around 5,000km of overhead transmission lines in the north of Scotland. We are responsible for maintaining and investing in this transmission network, which serves around 70% of the land mass of Scotland.

As the amount of renewable energy generation in Scotland increases, prompted by Scottish and UK government targets aimed at tackling climate change, changes in the electrical infrastructure are needed to allow the energy produced by these developments to reach areas where the power is required.

As owners of the electricity transmission network in the north of Scotland, we are required to make sure the electricity transmission network is capable of safely connecting and transmitting the energy produced by generators.

Project Background

In March 2010 the Crown Estate leased ‘option areas’ in the Pentland Firth and Orkney waters for the establishment of marine generation developments. These leased areas have the potential to generate up to 1600 MW (wave and tidal) of electricity. Two of these leased areas are in close proximity to Gills Bay and have a combined potential of 500 MW of tidal energy.

We have received initial applications to connect these sites to the electricity network. In order for this electricity to reach the centres of demand it will need to be connected to the transmission network at Dounreay. The existing network in the Gills Bay area is 11kV distribution with a new 33kV line being installed by 2012. These connections do not have sufficient capacity to connect the potential generation from the new tidal developments.

Currently the closest high voltage (132kV) transmission line runs between Dounreay to Thurso and south to Beauly, this line is currently at capacity and any additional generation in this area would need to be exported using the 275kV connection between Dounreay and Beauly, therefore a connection to Dounreay is required for this project.

Helping to Secure a Renewable Future: Proposed Gills Bay 132kV / 33kV Substation

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Proposed Gills Bay 132kV / 33kV Substation

Project Description

The project requires the construction of a new substation in the Gills Bay area and two new overhead lines from Gills Bay to Dounreay.

The project will consist of two phases:

Phase 1

Phase 1 will provide enough capacity to enable the marine developers to test and develop the technology but will not provide enough long term capacity for the full potential of the leased areas.

Phase 1 will consist of:

Construction of a new 132kV AC (Alternating Current) enclosed substation close to Gills Bay to provide a connection point for the marine developers. The substation needs to be enclosed to protect the equipment due to the proximity to the coast.

Installation of new 132kV overhead lines from Gills Bay to Dounreay - these would be of a wood pole construction.

The developers are responsible for bringing their cables ashore and connecting to the new substation, and may also require small buildings to house some infrastructure.

Phase 2

Phase 2 will be required if there is sufficient demand from the marine developers for capacity above that provided by Phase 1. The projected generation from these two developments (500MW) exceeds the capacity of Phase 1 (approx 180MW firm connection). Therefore a new facility may be required using High Voltage Direct Current (HVDC) to transmit the additional generation.

Phase 2 will consist of:

Construction of an HVDC Converter station (converts the AC power to DC) adjacent to Phase 1 132kV substation

Installation of a new DC buried cable from the converter station to a proposed HVDC switching station north of Wick and a subsea cable to Peterhead.

Overview Project Map

Consultation Process

This project is still in the very early stages of development and as such no decisions have been made about the location for the substation or the route and landing point for the subsea cable. We firmly believe that early and regular communication and consultation with those likely to be affected by the proposal forms a critical part of its development.

As a result, no decisions will be made until full consideration has been given to the comments, views and suggestions provided by statutory and key consultees, elected representatives, communities likely to be effected by the proposals and any other interested parties.

The current programme for Phase 1 of the project is shown below. The second half of the programme is entirely dependant on the developer accepting their connection quote in July of this year.

Developer connection application received Dec 2010 Compare site / route option Ongoing Identify preferred site / route July 2011 Developer accepts connection quote July 2011 Publish consultation document August 2011 Issue scoping request October 2011 Identify proposed site / route November 2011 Complete environmental impact assessment August 2012 Apply for consents August 2012 Start construction April 2013 Phased completion and commissioning 2014 – 2016

Have Your Say

This exhibition is your opportunity to comment on and ask questions about our proposals so far. We would greatly appreciate it if you would take the time to fill out our short questionnaire and post it in the comments box.

Alternatively, you can write to:

Lisa Kelly Scottish Hydro Electric Transmission Ltd 10 Henderson Road Inverness

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Proposed Gills Bay 132kV / 33kV Substation

Development Process - Phase 1

Substation

Earlier this year we identified 7 possible sites for the substation (see figure opposite). These were selected through a process of high level screening giving due consideration to technical feasibility, proximity to the generators seeking connection, cost and known environmental constraints.

Initial discussions were held with a number of statutory and key consultees including Highland Council, Scottish Natural Heritage and the Scottish Environment Protection Agency in order to gain a greater understanding of the key factors likely to influence development at each site. These discussions, as well as further assessment of the technical issues have led us to rule out development at 4 of the initial 7 sites.

The remaining 3 sites are currently undergoing detailed assessment to further inform the site selection process, after which a preferred site will be selected with full consideration given to all the comments received through this stage of consultation.

Overhead Lines

An initial high level screening of baseline information has been carried out for potential overhead line routes from each possible substation location to Dounreay Substation. This has identified two main corridors 2km wide that will be subject to extensive survey work to determine a viable route within the corridor.

The overhead lines are assumed to be of woodpole construction, to a ‘Trident’ specification, which are approximately 11m high. See photo below of typical Trident installation.

Two circuits may be required to provide the Developers with a ‘Firm’ connection, this means that if there is a fault on one line there will be an alternative available. During our preliminary discussions with the statutory consultees it was agreed that the two lines would not be constructed in close proximity to each other due to visual impact and potential increase in bird issues. This has led to the development of one corridor along the north coast and another running south west to our proposed new facility at Spittal and then north west to Dounreay. See map on Poster 2.

There will be approximately 87km of new overhead line required for this project if both lines are constructed.

There may well be a requirement for mitigation measures to reduce the visual impact and the impact on wildlife pending further detailed environmental assessments.

Connection to the Substation from the Developments

The developers are still to decide on the location of their landfall for bringing ashore the cables and any associated infrastructure. It is likely that the cables would be buried from the landfall point to the new SHETL substation. The Developers may also require some smaller buildings, ideally located adjacent to SHETL’s substation. These decisions are yet to be made and liaison is ongoing with the developers to mitigate the impact of the connections.

Typical Trident Woodpole Overhead Line

Substation Site Options

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Proposed Gills Bay 132kV / 33kV Substation

Substation sites in detail

Following initial discussions with statutory authorities and key consultees, three possible substation sites have been selected to be taken forward for further assessment and comparison. This includes detailed environmental studies, further baseline information gathering and continued consultation.

The following sections highlight some key considerations currently identified for each of the three sites. The visualisations shown for each site are only preliminary and have been produced to give an indication of the scale of the development within the surrounding landscape only. These will be updated as further information becomes available and detailed design is undertaken. The detailed design will refine the following aspects that are likely to affect the visual impact:

Technical specification (determines building size) Design of building exterior Foundation level and corresponding ridge height

Orientation of building Opportunity for landscaping (e.g. earth bunding and screen planting)

Site D

Viewpoint 1

Viewpoint 3

Considerations

Environmental The site lies on agricultural land Site is frequented by geese Although located on relatively high

ground, the site is backdropped by forestry and sheltered from many view points by existing shelterbelts and

plantations. A few properties are in very close

proximity to the site. Construction effects on these properties will therefore need to be considered.

Technical The site will require minimal cut and fill to create the platform. Soils are fairly shallow, therefore some

rock excavation would be required Access to the site would be from

existing access to Philips Mains Drainage works will be required to

manage hill runoff.

Economic Indicative costing are currently being calculated.

Site E

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Considerations

Environmental The site lies on agricultural land. Site is frequented by geese A historic site lies within 500m of the

site. Although located on relatively high

ground, the site is backdropped by forestry and sheltered from many view points by existing shelterbelts and plantations. A few properties are in very close

proximity to the site. Construction effects on these properties will therefore need to be considered.

Technical The site will require minimal cut and fill

to create a level platform. There are shallow soils and therefore

some rock excavation may be required Access to the site would be from

existing access to Philips Mains Drainage works will be required to

manage hill runoff.

Economic Indicative costs are currently being calculated.

Viewpoint 1

Viewpoint 3

Proposed Gills Bay 132kV / 33kV Substation

Site F

Viewpoint 2

Viewpoint 3

Considerations

Environmental The site lies on agricultural land. Site is frequented by geese The site is located on low lying flat

area of land and is well screened from most viewpoints by plantations The area is prone to surface water A few properties are in very close

proximity to the site. Construction effects on these properties will therefore need to be considered.

Technical The site may require raising or significant drainage works to provide a dry platform There are shallow soils. Access to the site could be from the

west or via Philips Mains Existing overhead lines may need to

be moved.

Economic Indicative costs are currently being calcu-lated

Aerial View of Typical Layout

Phase 1

Phase 2

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