The industry’s first offshore reactive compensation station (RCS) – a key technology for the long-distance transmission of high voltage alternating current (HVAC) – has been installed at the Hornsea 1 wind farm under development by Orsted in the UK North Sea.

The facility, made up of a 2,500-tonne topside and 1,500-tonne jacket, has been piled in roughly halfway between the 1.2GW project’s site 120km off the coast of Britain and the National Grid’s onshore connection point.

Production from Hornsea 1’s 174 Siemens Gamesa 7MW turbines will travel along medium voltage cabling to the wind farm’s trio of offshore substations, where it will be stepped to high voltage to reduce losses during onward export to shore as HVAC via the RCS.

“As we build offshore wind farms further and further out to sea we need to develop innovative ways to work with the longer cable lengths,” stated Duncan Clark, Hornsea 1 programme director.

“Whilst RCSs have been used onshore previously, for Hornsea 1, [being] 120km out to sea, we have been working closely together between our engineering team and external contractors to deliver the world’s first offshore RCS.

“The successful installation of the RCS is an important milestone for the whole offshore wind industry as we continue to build far-offshore wind farms with generating capacities of the same order as conventional power plants.”

Once fully operational in 2020, Hornsea 1 will be the world’s biggest wind farm, producing enough power to meet demand from over one million UK homes