Siem Offshore has cleared rocks and boulders along the proposed route for the subsea cable for SSE's 1.2GW Caithness-Moray transmission project, which will link renewable energy from the north of Scotland to areas of demand.
The work was carried out by the Siem Ruby vessel, which used a subsea boulder clearance plough, said Scottish and Southern Electricity Networks, SSE’s grid business.
The same vessel will also create a trench for the cables, which will be installed from a purpose-built cable laying vessel in two campaigns.
The first will run from Noss to the midpoint of the cable route and the second from Portgordon to the end of the previously laid cable, SSE said.
Following installation, the plough will be reconfigured to backfill the trench using the seabed material previously excavated during the trenching operation.
The £1.1bn Caithness-Moray project is on schedule for completion in 2018, the company added.