Danish developer Ørsted has reported that the final 7MW Siemens Gamesa turbine has been installed by Fred Olsen Windcarrier at the UK’s giant 1.2GW Hornsea 1 project, currently the world’s largest offshore wind farm.

The Bold Tern vessel had been sharing construction duties at the 407km2 North Sea development site with DEME’s Sea Challenger, which piled-in the turbines’ monopile foundations.

“The milestone of this last turbine being installed only nine months after the first one was erected is just one small part of this record-breaking project,” said Ørsted’s Hornsea 1 programme director Duncan Clark . “Hornsea One has truly paved the way for the next generation of offshore wind farms.

“At the time of taking on the project, it’s scale and the technical pioneering required seemed a Herculean challenge, but a truly extraordinary effort from all those involved have managed to make this impressive feat of engineering the new norm.

“We have benefitted from fantastic working relationships with contractors and suppliers, and that includes vessel providers … [in] ensur[ing] that turbine installation has been concluded on time and within budget.”

The Bold Tern installed four of the Siemens Gamesa SG7.0-154s a trip, loading up out of Siemens Gamesa’s Hull assembly facility to travel the 120km out to Hornsea 1, and erecting each machine in an average of 12 hours.

Once fully commissioned, the record-setting wind farm will supply power to well over 1 million British homes.

Hornsea 1 suffered a technical fault in August that contributed to a massive power outage on the UK grid.

In a statement sent to Recharge at the time, an Orsted spokesperson said: “During a rare and unusual set of circumstances affecting the grid, Hornsea 1 experienced a technical fault which meant the power station rapidly de-loaded – that is it stopped producing electricity. We are fully confident should this extremely rare situation arise again, Hornsea 1 would respond as required.”