Mainstream Renewable Power (Mainstream) and Ocean Winds have partnered to develop a second ScotWind site of 500 MW east of Shetland, expanding the overall footprint of the Arven Offshore Wind Farm (Arven) to 2.3 GW.

Arven comprises two sites. The first is the 1.8 GW site east of the Shetland Islands which was awarded to the 50:50 joint venture between Mainstream and Ocean Winds as part of the ScotWind leasing process in 2022. Separately, Ocean Winds – an international joint venture between EDPR and ENGIE dedicated to offshore wind energy – was awarded a 500 MW site in the same NE1 block. Mainstream has now completed its acquisition of a 50% shareholding in Ocean Wind’s holding company and the two sites are now being developed jointly to maximise their potential.

Mainstream and Ocean Winds have a longstanding partnership. The companies are currently developing a 1.2 GW floating offshore wind farm in South Korea and are in a consortium for the upcoming Utsira Nord floating offshore wind tender in Norway. By extending this partnership and developing the two sites off Shetland, Mainstream and Ocean Winds will leverage their combined expertise to maximise benefits for Shetland and Scotland, create supply chain opportunities and jobs, whilst contributing to the UK’s net zero ambition.


The partners have commenced early-stage local engagement, meeting with supply chain partners, local authorities and fisheries representatives.

Adam Morrison, UK Country Manager for Ocean Winds, said:

"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.

"We have already commenced surveys and a programme of early local engagement, including the fishing industry, and we are committed to working closely with the local community in developing this larger Arven project, which will be a significant driver for the energy transition."

Tove Røskaft, Head of Offshore Wind for Mainstream, said: "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.

"Mainstream has a solid track record in Scotland and the UK, having successfully developed the Neart na Gaoithe and the Hornsea zone which is the world’s largest offshore wind farm in operation. This remains a core offshore wind market for Mainstream and we look forward, together with Ocean Winds, to continuing our engagements with Crown Estate Scotland and other key stakeholders."