Shetland HVDC Connection

Contracts for construction were awarded in August 2020. As of Aug 2020, enabling works were due to begin within a month. Construction of the AC Substation, and HVDC Convertor and Switching Stations, was due to start in early 2021. The subsea cable installation is expected in 2022 and 2023. [1]

The interconnector will start at the Upper Kergord Valley converter station in Shetland. From the converter station an underground cable will be laid to a landing area in Weisdale Voe. From there, a subsea cable will run to landfall at Noss Head in Caithness, with onward connection to an HVDC switching station north of the village of Staxigoe in Caithness.[2][3]

The route of the cable will cross TAT-10, TAT-14 and Atlantic Crossing 1 telecommunication cables and the Piper–Flotta oil pipeline.[4]

The interconnector will connect to the existing 320kV Caithness - Moray Link to form a three terminal HVDC network, with converter stations at Spittal in Caithness; Blackhillock Substation in Moray; and Upper Kergord on Shetland. The Shetland leg will have a power rating of 600MW;[5] the Spittal and Blackhillock converters are rated at 800MW and 1,200MW respectively.[6] This will be the first multi-terminal HVDC interconnection in Europe.[7]

The project is being developed by Scottish Hydro Electric Transmission, a subsidiary of SSE plc.

It is estimated that it will cost more than £600 million.[8] The project is needed for development of Shetland's renewable energy potential and it is necessary for the projects such us the Viking Wind Farm and the Aegir wave farm.[9][10]

It also contributes to the security of Shetland's elelctricity supply,[8] especially as Lerwick Power Station is nearing the end of its operational life.[11]

The project was proposed in 2007.[4] In January 2008, the report published by the Crown Estate found the project would be "economically and technically possible".[12] At the same year, Scottish Hydro Electric Transmission filed planning application and started public consultations.[13]

Originally, the cable was planned to run from Shetland to 320 kilometres (200 mi) to Portgordon on the Scottish mainland,[13][14][15] and then on to Blackhillock substation, near Keith, Moray via 25-kilometre (16 mi) underground cable.[13][15] However, the end point was moved to Caithness, and the remaining part of the connection was constructed separately as the Caithness - Moray Link.[2]

In 2019, Ofgem announced that it was minded to authorise construction, subject to the Viking windfarm winning a CfD contract in the government auction held in September 2019. Viking Energy was unsuccessful in this auction, putting the future of the interconnector in doubt. [16] [17]

SSEN submitted a revised proposal in January 2020. Ofgem carried out a final consultation on this revised proposal, and concluded in April 2020 that it would grant conditional approval for the link, conditional on Ofgem receiving sufficient evidence by the end of 2020 that the 457 MW Viking Wind Farm project is likely to go ahead.[5]

In April 2020, Ofgem approved revised proposals for the project, subject to "evidence that the Shetland Viking Wind Farm project will go ahead".[5]

On 17 June 2020, the Viking Wind Farm sponsor, SSE Renewables, made a final investment decision to proceed with the wind farm investment, conditional on certain industry code modifications, and "the outcome of the consultation on Ofgem’s minded-to position to approve the transmission link, expected in July 2020".[18] According to Shetland News, this meant that both the Windfarm and the HVDC Connection "are likely to go ahead".[19]

On 16 July, Ofgem gave final approval for the connection.[20]

• Caithness - Moray Link, the other arm of the 3-way HVDC network.

• HVDC Project website
• Shetland energy project website
• Map of the indicative route in Shetland (PDF)
• Map of the indicative offshore route (PDF)
• Map of the indicative route in Moray (PDF)