On June 14, the United Kingdom and Japan struck a landmark cooperation deal on offshore wind in London. UK Prime Minister Keir Starmer and Japanese Prime Minister Sanae Takaichi formally signed the Offshore Wind Industrial Compact. Serving as a core supplement to the bilateral Joint Declaration on Economic Security Cooperation, the compact is designed to deepen joint collaboration across offshore wind financing, technological R&D and supply chain development.
Under the agreement, Japan will inject up to £9 billion (approximately USD 21.1 billion / EUR 10.4 billion) into UK offshore wind projects. Cooperation will centre on Britain’s floating offshore wind sector, prioritising a batch of benchmark projects with a combined capacity of 5.9 GW, with Japanese companies holding equity stakes in multiple key schemes. Detailed development plans and consortium structures for three flagship projects have been finalised:
Ossian Project (3.6 GW)
The largest wind scheme covered under the partnership, Ossian sits 84 kilometres off Scotland’s east coast in waters 72 metres deep and remains in the survey and planning phase. Developed jointly by Copenhagen Infrastructure Partners from Denmark, UK-based SSE Renewables and Japan’s Marubeni Corporation, it will deliver a major boost to Britain’s floating wind capacity in the years ahead.
Green Volt Project (560 MW)
Located 80 kilometres from Scotland’s eastern shore, the project is co-developed by Flotation Energy, a floating wind firm under Tokyo Electric Power Company (TEPCO), and Vårgrønn, a joint venture backed by Italian and Norwegian investors. It has secured all onshore and offshore planning consents and was awarded a Contract for Difference by the UK government in September 2024, with grid connection targeted for 2029.
Erebus Demonstration Project (100 MW)
This pilot scheme is developed by Blue Gem Wind, a joint venture between Ireland’s Simply Blue Energy and France’s TotalEnergies. Japan’s Kansai Electric Power Co., Inc. has acquired a stake in Simply Blue Energy to participate deeply in project delivery. Construction is scheduled to kick off between 2026 and 2027, acting as a vital testbed for floating wind technology deployment in the UK.
Prime Minister Keir Starmer stated that this landmark deal will bring billions of pounds of investment to the UK, generate tens of thousands of new jobs and drive forward the growth of the domestic wind industry.
This strategic offshore wind partnership also forms a key pillar of broader UK-Japan collaboration spanning infrastructure, green finance and advanced technologies. Both nations have officially named offshore wind a top priority for long-term joint development.
