Sumitomo takes third of EDF's Gwynt Glas floating wind project
Japanese conglomerate's 33% stake in 1.5GW Celtic Sea farm extends Asia's push into European floating wind ahead of 2040 domestic targets.
Sumitomo acquired a 33.33% stake in the Gwynt Glas floating offshore wind farm off the coast of Wales, entering a three-way partnership with EDF and ESB in the 1.5GW Celtic Sea project, the companies said on Monday (2026-08-10).5
The deal extends a £9 billion investment commitment between Japan and the United Kingdom for offshore wind development announced earlier this year, with 5.9GW of floating capacity now backed by Japanese capital including the Ossian, Green Volt and Erebus projects. Floating technology is central to Japan's plans to install 30-45GW of offshore wind by 2040, with floating farms expected to account for between half and a third of that total.5
Gwynt Glas submitted its scoping report to the Planning Inspectorate this summer. Matthieu Hue, EDF Power Solutions UK and Ireland CEO, said Sumitomo's "extensive global experience in offshore wind development and investment complements our own and ESB's, creating a powerful partnership dedicated to delivering this vital project."5
The Celtic Sea farm is one of three UK floating developments drawing Japanese backing. TEPCO is a partner in Flotation Energy, co-developer of the Green Volt project, while KEPCO holds 80% of Simply Blue Group, behind the 100MW Salamander floating wind scheme.5
Sumitomo has been active in European offshore wind but appears to be restructuring its holdings. The conglomerate completed the sale of stakes in two Belgian offshore wind farms to JERA Nex bp, the 50:50 joint venture between BP and Japan's JERA, in early July (2026-07-06). Nobelwind, commissioned in 2017 with 165MW capacity, and the 219MW Northwester 2 farm, which started generating power in 2020, were transferred as part of that transaction.2,3
JERA Nex bp was formed to consolidate BP's Japanese offshore wind projects and expand the partnership into European waters. BP's Aomori and Akita developments in Japan were folded into the venture, though a Yamagata project reportedly could not be incorporated and BP withdrew from it separately.4
Sumitomo has also moved into UK battery storage through Summit Transition Partners, its joint venture with Taiwan's TPK Holdings. The acquisitions, which closed in late May (2026-05-27), included the 240MW/480MWh Cockenzie project in East Lothian and stakes in the Yorkshire-based Monets Garden and Elland 2 sites. STP also took a 25% holding in the 57MW/114MWh Lister Drive scheme and the 240MW/480MWh Ocker Hill project in the West Midlands.1
The shift in Sumitomo's offshore wind portfolio — selling mature European generation assets while buying into earlier-stage floating projects — suggests a focus on next-generation technology ahead of domestic capacity build-out. Floating wind remains commercially unproven at scale. Gwynt Glas faces permitting and grid connection risks common to Celtic Sea projects, and the UK's contract-for-difference auction track record for floating wind has been patchy.
Whether the Gwynt Glas partnership secures a CfD allocation in the next UK allocation round, and whether Japanese utilities continue to divest fixed-bottom European wind stakes to fund floating exposure closer to home, will determine the trajectory of this bet.5,3