Scottish and Southern Electricity Networks (SSEN) has asked Ofgem for conditional approval of its ‘Final Needs Case’ for a subsea cable transmission link from Western Isles to the Scottish mainland.
If developers commit to new generation in the 2019 CfD auction, SSEN would install a single 600MW subsea circuit from Arnish on Lewis to Dundonnell on the Scottish mainland at a cost, according to the Guardian, of £650-700 million. This would connect to SSEN’s Beauly substation near Inverness via underground cables.
The project has four main elements:
- HVDC converter and associated AC substation at Arnish Point, Stornoway
- HVDC converter and associated AC substation within the existing Beauly substation footprint
- HVDC underground cable between Beauly Substation and Dundonnell, on the west coast
- HVDC subsea cable between Arnish Point and the land fall at Dundonnell
SSEN said a 600MW HVDC connection was the optimal solution, assuming that the two largest transmission contracted generation schemes - Stornoway wind farm and Uisenis wind farm - secure a CfD in the May 2019 auction.
Dave Gardner, SSEN’s director of transmission, said: “Today marks a significant milestone in providing a transmission connection to the Western Isles. We believe our proposal represents a robust, economic case for reinforcement and provides the best possible opportunity to unlock the renewable potential of the Western Isles.”
If it goes ahead the project could be completed by 2023.
Meanwhile developers on Shetland await progress on a second offshore link between Shetland and Caithness. A 260km HVDC link has long been proposed to allow projects like the proposed Viking Energy and Beaw Field wind farms to export energy to the mainland.