Environmental impact of bringing offshore electricity into national grid system at Crystal Rig wind farm 

The environmental impact of running a cable from Thorntonloch near Torness power station to the electricity sub station at Crystal Rig wind farm in the Lammermuirs to take electricity from the proposed offshore wind farm in the Firth of Forth is being investigated prior to a planning application being submitted to East Lothian Council.

Mainstream Renewable Power Ltd propose developing an offshore wind farm, Neart na Gaoithe, in the Firth of Forth, 15.5 km directly east of Fife Ness. The offshore wind farm will have between 64 and 125 turbines and have a capacity of 450 megawatts (MW).

A grid connection for the Neart na Gaoithe offshore wind farm has been secured at Crystal Rig II onshore wind farm in East Lothian, with a landing point for the cable proposed at Thorntonloch. The onshore grid connection works will consist of two transmission pits, six individual cables (laid in two groups of three) buried within trench(es) for a distance of approximately 12km from the landfall at Thorntonloch to Crystal Rig II; and a new electrical substation adjacent to the existing Crystal Rig II substation.

Developers Mainstream Renewable Power Ltd have produced a scoping report, based on survey work carried out by LUC consultants, which outlines the environmental issues they believe need to be addressed and requesting a scoping opinion from East Lothian Council prior to submission of the planning application. All comments about the environmental impact of the proposed cable and its installation need to be submitted before February 10.

The underground cable will be routed along a corridor from Thorntonloch beach, approximately 8km south-east of Dunbar, travelling westwards then south-westerly to Crystal Rig II onshore wind farm.

Much of the cable route will be installed in open field and for these sections all construction works will lie within a 20m wide area along the proposed route and a temporary haul road will be established.

Further investigation and survey work both onshore and offshore is currently being done to identify local constraints along the route, and the possible impact on birds, cultural heritage, landscape, geology and agricultural use, water courses, traffic, air quality noise and vibration, tourism and recreation, and the cumulative impact.

The proposed corridor for the cable is surrounded by five Sites of Special Scientific Interest (Woodhall Dean, Barns Nest, Rammer Cleugh, Lammermuir Deans and Pease Dean, but the route itself is not within an SSSI. There are, however, over 50 recorded cultural heritage features and site within the route corridor, spanning from prehistoric settlement and burial remains to World War II military structure, plus eight scheduled monuments.

Consultants carrying out the environmental impact survey report that although there are no areas of particularly high ornithological interest within the onshore works boundary, there could be a permanent reduction in breeding or wintering bird populations, and the work could impact on bats if there was tree felling which would fragment the bats’ flight lines and feeding paths.

The consultants, point out that the introduction of the substation into an upland location will change the views of the site at Crystal Rig but as it would be next to the existing large-scale substation it is “unlikely to be regarded as a major new change in the view”. The long term visual effects of the buried cable are unlikely to be significant, however, the temporary construction activities of excavation and vegetation removal likely to be required will be much more visible from the surrounding area.