Shetland transmission project : SSEN Transmission finalizes main contracts

Scottish and Southern Electricity Networks Transmission (SSEN Transmission) has taken the Shetland transmission project forward by appointing the main contractors for the construction of the 600MW HVDC transmission link and all related infrastructure.

The high-voltage direct current (HVDC) interconnector project, which will connect Shetland in Scotland to the UK mainland, secured final approval from Ofgem in July 2020.

SSEN Transmission said that everything is now in place to begin the main construction on the Shetland transmission project in late August.

The transmission link project is being taken up to enable the connection of new renewable energy projects in Shetland apart from supporting the future security of supply requirements of the Scottish region.

The Shetland transmission project will involve the construction of an AC Substation at Kergord on Shetland, which is needed for the connection of renewable electricity generators in the region for backing the transition to net zero emissions. SSEN Transmission said that these works will be carried out under the leadership of Siemens BAM, which has been building substations for the company across northern Scotland.

Also part of the project is an HVDC converter station at Kergord where power will be converted from alternating current to direct current before it is transmitted nearly 270kms through a 257km long underground and subsea cable to an HVDC Switching Station at Noss Head, Caithness in northern Scotland.

SSEN Transmission finalizes main contracts for the Shetland transmission project. Photo courtesy of SSE.

Marine cable solution provider NKT will handle the manufacturing and installation of the subsea cable, while BAM Nuttall will carry out all civil engineering works, which will include the construction of all buildings. On the other hand, HVDC technology provider Hitachi ABB Power Grids will be responsible for providing and commissioning the HVDC system for the Shetland transmission project.

Subsequently, the renewable power originating from Shetland will be transported through the Caithness Moray HVDC link before it is reconverted to alternating current for onward transmission to address the electricity demand requirements of homes and businesses across northern Scotland and beyond.

Commenting on the Shetland transmission project contract, Niklas Persson – Managing Director of the Grid Integration at Hitachi ABB Power Grids, said: “Our advanced HVDC technology will bring clean electricity to consumers and enable the sharing of renewable resources by interconnecting Shetland with mainland Scotland.

“We value this opportunity to further grow our partnership with SSEN Transmission. Being part of this innovative project is another example of Hitachi ABB Power Grids’ commitment to a sustainable energy future and a partner of choice for enabling a stronger, smarter and greener grid.”

SSEN Transmission said that enabling works are slated to start at Kergord and Noss Head towards the end of this month, with full construction of the AC substation, and HVDC convertor and switching stations to begin in early 2021.  On the other hand, subsea cable installation will be taken up in 2022 and 2023 after it is manufactured.

Sandy Mactaggart – SSEN Transmission Director of Offshore Delivery, commenting on the Shetland transmission project contracts, said: “We are delighted to have finalised contracts with our supply chain partners for the Shetland HVDC link, building on the experience and strong track record we have collectively established over recent years following the construction and operation of the Caithness Moray link.

“All four contractors are leading specialists in their field, building the high quality and reliable infrastructure required to meet Shetland’s future energy needs and contribute to UK and Scottish net zero targets.

“The Shetland HVDC link will deliver substantial socio-economic and environmental benefits to Shetland’s, Scotland’s and the UK’s economy, supporting hundreds of skilled jobs in the process as part of the green recovery from the coronavirus pandemic.”