Irish renewable energy company Mainstream Renewable Power and Ocean Winds, a 50:50 joint venture between EDPR and Engie, have joined forces to build a second 500MW floating offshore wind farm off the east coast of Shetland in Scotland, expanding the overall footprint of the Arven offshore facility to 2.3GW.

The first wind farm to be developed there was a 1.8GW site.

The two companies have begun early-stage local engagement with local governments, representatives of fisheries and supply chain partners.

In November 2022, Mainstream and Ocean Winds entered a seabed lease agreement with Crown Estate Scotland for the 1.8GW project under the ScotWind Offshore Auction.

Arven includes two sites 22km offshore the east of the Shetland Islands. Both are within the larger NE1 area, under Crown Estate Scotland.

The project site has water depths of 100m.

Expected to commence operations in the early 2030s, the wind project will generate enough clean power for two million homes while avoiding three million tonnes of carbon dioxide emissions annually.

In a separate move, Ocean Winds secured the contract for a 500MW site in the NE1 block. Mainstream’s purchase of a 50% interest in Ocean Wind's holding company means that the two sites are now being jointly developed.

Ocean Winds UK country manager Adam Morrison stated: “The collaboration between Ocean Winds and Mainstream Renewable Power marks a significant milestone, combining our expertise and resources to develop our largest floating offshore wind farm to date. This experienced partnership will capitalise on delivery experience both in Scotland and internationally".

Mainstream Renewable Power offshore wind head Tove Røskaft stated: “Arven offers a unique combination of scale, world-class wind resource and routes to market, which enable it to deliver a range of compelling benefits for the good of Shetland, Scotland and the UK".