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Project Report

Route Selection, Consultation and EIA Studies for a Dounreay–Orkney 132 kV Grid Connection

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Client: Scottish Hydro-Electric Transmission Ltd
Date: 2007-ongoing
Location: Scotland (UK)

Scottish Hydro-Electric Transmission Limited (SHETL) is researching and consulting on a proposal to develop a new high voltage electricity transmission circuit capable of accommodating output from possible renewable generation developments located on the Orkney Islands and to connect this to the existing mainland transmission network at Dounreay, Caithness. As it is SHETL policy that the route selection process be environmentally led, Aquatera has conducted a range of desk- and field-based studies to provide route options, a preferred route on which to consult, and will carry out EIA studies on the proposed route as it becomes defined.

Studies were undertaken initially in 2007 to identify all possible route corridors within a study area encompassing parts of Orkney, Caithness and Sutherland. A desk-based study screened the area for all relevant environmental sensitivities and constraints to allow route options to be established. This was followed by more detailed desk and site-based work to assess the relative merits of these options and the selection of the preferred route for consultation.

As the Orkney 132 kV Connection would comprise a number of related constituent parts, including:

  • Overland connections based upon overhead lines
    (with under-grounding considered where/if necessary)
  • Possible interim/secondary sub-stations in Orkney
  • Landfalls for the cables in Orkney and Caithness
  • Subsea sections of cable

Any assessment must balance the relative sensitivities of each of these phases across the whole length of the route when deriving a preferred option.



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