The United Kingdom and Japan signed an Offshore Wind Compact during Prime Minister Sanae Takaichi's weekend visit to Downing Street, with Tokyo agreeing to channel up to £9 billion, roughly $12.08 billion, into British floating wind projects. The deal was one of several G7 partnerships announced alongside Prime Minister Keir Starmer, and Downing Street framed it as a step toward reducing UK reliance on volatile fossil fuel markets.
The capital will back three projects in which Japanese companies already hold stakes. Ossian, a 3.6 gigawatt floating array planned for waters 72 meters deep off Scotland's east coast, is owned by Denmark's Copenhagen Infrastructure Partners, the UK's SSE PLC, and Japan's Marubeni Corp. Green Volt, a 560 megawatt project also off Scotland, counts Flotation Energy, a subsidiary of Tokyo Electric Power, among its owners. The 100 megawatt Erebus demonstration in the Celtic Sea includes France's TotalEnergies and Japan's Kansai Electric Power, the latter through a recent stake in Simply Blue Energy.
The 5.9 gigawatts of combined capacity would be one of the largest single pushes of foreign capital into UK floating wind to date. Ossian is projected to avoid up to 7.5 million metric tons of carbon emissions per year, while Green Volt secured a contract for difference from the UK government in September 2024 and is targeted for commissioning in 2029. Erebus plans to begin construction in 2026 or 2027.
The compact sits alongside other energy agreements signed during the visit. Hitachi Energy committed £18 million to a facility in Stafford, Rolls-Royce will work with the UK National Nuclear Laboratory and Japan's Atomic Energy Agency on advanced reactors, and the UK Atomic Energy Authority agreed to collaborate with Japan's National Institutes for Quantum Science and Technology on fusion research.
For the offshore wind sector, the deal arrives at a moment when developers across Europe have warned that floating projects need deeper capital pools and clearer offtake to clear final investment decisions. Locking in Japanese utility and trading house money, alongside existing European sponsors, gives the Scottish and Celtic Sea pipeline a path through a financing environment that has stalled comparable plays in the United States.