Offshore construction of Neart na Gaoithe (NnG) offshore wind farm is well underway since it began in August 2020. Over the last few months, construction vessels have been preparing the seabed in the nearshore area of Thorntonloch ready for the installation of two offshore electricity transmission cables.
NnG ‘s Export Cable Contractor, Prysmian Group, is supplying and installing the two export cables. The cables, each approximately 37km long, will connect the two offshore substations to the landfall, at Thorntonloch Beach in East Lothian. These will supply the electricity generated by the turbines to the onshore substation located at Crystal Rig wind farm in the Lammermuir Hills, approximately 12.3km from the landfall location, via the two onshore cables.
Two horizontal directional drills, passing directly underneath the landfall location of Thorntonloch beach, were successfully completed in early 2021 with ducting installed. This will enable the offshore cables to feed through and join with the onshore export cables.
The first cable will be transported to the nearshore area Thorntonloch Beach in mid- June by Prysmian Group’s large cable laying vessel, the Cable Enterprise. The second cable will be brought to the nearshore area in July (the work is weather dependent, so dates are subject to change).
The nearshore section of each cable will be pulled through the horizontal directional drill ducting by an onshore-based winch, to join to the onshore cables behind Thorntonloch Beach.
The Cable Enterprise will then gradually sail out towards the NnG site, laying the cable between the drill exit point and the offshore wind farm, ready to be buried. Once laid on the seabed, the cables will be patrolled by small workboats and guard vessels.
The offshore sections of the two cables will be safely buried from the nearshore area out towards the wind farm by remotely operated vehicles launched from the Normand Pacific cable burial vessel.