Ploughing on with Caithness-Moray cable

Siem Ruby

A key milestone for the Caithness-Moray transmission project was reached this week following the successful clearance of rocks and boulders along the proposed route for the subsea cable.

This is the first in a series of major offshore activities throughout 2017 that will allow the installation of two high voltage direct current (HVDC) cables that will be capable of carrying up to 1,200MW of electricity between Caithness and Moray. The Caithness Moray project is required to transport renewable electricity from across the north of Scotland to areas of demand across Scotland and beyond.

The route for the cable was cleared by the Siem Ruby vessel, which utilisies a specialist subsea boulder clearance plough, safely clearing the route of boulders along the seabed. The same vessel will subsequently be used to create a trench to lay the cables within it. The cables will then be installed from a purpose-built cable laying vessel in two campaigns – the first from Noss to the midpoint of the cable route and the second from Portgordon to the end of the previously laid cable.

Following the installation of the cables the plough will be brought back and reconfigured to backfill the trench using the seabed material previously excavated during the trenching operation.

Lead Project Manager Brian Mitchell said: “This is a significant milestone for the Caithness-Moray project as the plough has literally cleared the way to allow our team to start laying the cables that will enable electricity to be transported between Caithness and Moray.

“Once complete, the Caithness Moray subsea link will significantly reinforce the north of Scotland transmission network and aid our transition to a low-carbon economy.”

The Caithness-Moray project is on schedule for completion in 2018, enabling a further 1,200MW of renewable generation capacity to connect to the grid. A recent study in to the economic contribution of the project showed that it will deliver a £634.5m boost to the UK economy, supporting over 10,000 years of employment.

The £1.1bn project represents the largest investment in the north of Scotland’s electricity network since the hydro development era of the 1950s and is also the largest capital investment project undertaken by the SSE Group to date. It is also the largest Living Wage contract ever awarded in the UK, demonstrating SSEN’s strong commitment to ensure all employees working on its sites get a fair day’s pay for a fair day’s work.