The first 100 km of subsea cable has been installed in the North Sea as part of SSEN Transmission’s Shetland High Voltage Direct Current (HVDC) link project.
The £660m project involves constructing a 260 km subsea cable from Shetland to the GB mainland, linking Shetland to the national grid for the first time, as well as unlocking Shetland’s potential for future renewable energy generation.
Starting in July, the subsea HVDC cable was successfully pulled-in to where it makes landfall at Noss Head near Wick from aboard the specialist cable-laying vessel NKT Victoria and was installed onto the seabed as the vessel made its way out to sea to a point east of the Orkney Isles.
Once the cable was installed on the seabed, where possible it was trenched into position using Grand Canyon III, a multi-role construction support vessel with a specialist subsea jet trencher.
The successful installation of the first 100km of cable required careful coordination between the NKT Victoria, multiple subsea divers as well as the shoreside cable pull-in team at Caithness, who worked to install the cable through the previously constructed horizontal directional drilled (HDD) ducts at Noss Head in Caithness.
Onshore, teams have also completed the installation of the HVDC cables in Shetland.
The offshore team is now focusing on readiness for next year’s subsea cable installation campaigns, with the second campaign expected to begin in the spring.
This will involve another 57 km of cable from Weisdale Voe on Shetland heading south into the North Sea.
The third campaign will take place later in 2023, which will complete the link between the first and second campaigns in the North Sea to join all three campaigns together and complete the full 260 km subsea HVDC link.
SSEN Transmission Lead Project Manager Chris Finnigan said: “We’re delighted that the first cable laying campaign is complete, meaning the first 100km of the Shetland HVDC link subsea cable has safely been installed on the seabed heading north from the Noss Head shore.
“It has been a complex operation involving multiple parties, and we’re really pleased that this first campaign has been completed safely and successfully.”
The Shetland HVDC subsea link project is on track to be completed by 2024.