HDD ops starting at Shetland subsea link

NKT is about to kick off operations at Noss Head in Scotland to install the horizontal directional drilled (HDD) landfall for the Shetland HVDC Link.

NKT, on behalf of Scottish Hydro Electric Transmission, will be undertaking diving operations to assist with the HDD exit points for the subsea link.

Activities will include marine survey, diving operations and deployment of an anchor/mooring system at the site located approximately 400 metres offshore.

The works are scheduled to take place from 2 July until 20 September in waters around 19 metres deep.

The mooring and anchoring system will be set up during the duration of the works to support the diver. A high-resolution marine survey will then be completed to determine the exit point of the HDD holes, using a multibeam echosounder (MBES) and side-scan sonar (SSS).

The current program has three separate 4-5 day work phases, with a few weeks in between.

NKT landed the €235-million contract from SSEN Transmission last summer to deliver and install an interconnector to the Shetland HVDC Link project.

The turnkey order comprises the manufacturing of approximately 2×260 kilometres of 320 kV high-voltage DC on-and-offshore power cables.

The Shetland link will be the first transmission connection between the Scottish mainland and the island of Shetland.

Energy regulator Ofgem approved the HVDC subsea transmission link in July last year, after having rejected the project a year before.

Subsea cable installation will begin in 2022, with all construction work expected to be completed by the end of 2023.

The link is planned to begin generating 600MW of renewable energy by July 2024.