DEME's Japan offshore wind contract puts 15MW turbines in a new market
Japan Offshore Marine's Oga-Katagami-Akita deal is the first deployment of 15MW-class turbines in Japan and the first outside Europe and China.
DEME's Tokyo-based joint venture Japan Offshore Marine has secured a contract to install 21 Vestas V236-15MW turbines at the Oga-Katagami-Akita offshore wind project in northern Japan, covering engineering services and vessel charter for the turbine installation work.3 The agreement was signed with the project developer and represents both Japan's first deployment of 15MW-class turbines and the first use of that turbine capacity anywhere outside Europe, excluding China.3,4
Turbines at that scale have until now been largely confined to the North Sea and Chinese domestic projects, where state-backed developers pushed rapid local manufacturing. Putting a 15MW reference installation in Japan changes the procurement conversation across Asia-Pacific. Lenders and insurers typically price first-of-kind technology risk into project financing; with Vestas now able to point to a Japanese deployment, that discount narrows for other markets in the region.3
DEME Asia-Pacific offshore energy general manager Frank Jonckheere said the contract confirms that Japan Offshore Marine has become fully operational and is "well-positioned to onboard larger-scale offshore wind projects in Japan."3 The joint venture was established specifically to target the Japanese market, which has moved slowly compared to European or Chinese build-out but is beginning to award commercial-scale contracts.
Japan's offshore wind policy framework shifted meaningfully earlier this year, when the government finalized new auction rules after public consultations running from January to February 2026.5 The framework moves away from pure price competition toward criteria that include supply chain development and project deliverability — a change expected to favor established international developers with operational track records over purely cost-competitive bids.
The global offshore wind market is projected to grow to $208.33 billion by 2035 from $57.51 billion in 2026, supported by larger turbine deployment and expanded pipelines across Asia-Pacific.7 China leads regional deployment, but Japan, South Korea, Taiwan and Australia are all expanding development pipelines as governments raise renewable targets and turbine economics improve.
The contrast with the United States is direct. Offshore wind development has all but halted in the US amid the Trump administration's sustained attacks on federal leasing and permitting.1 Developer Ocean Winds, which struck controversial deals with the administration during the week of April 27, 2026 to abandon two US offshore wind projects, has simultaneously pushed ahead with European projects including a major floating wind milestone.2 Capital follows regulatory clarity, and right now Asia-Pacific and Europe offer more of it than the US.
In China, a separate offshore wind development is worth flagging. The China National Offshore Oil Corporation has launched a floating wind turbine designed to power offshore oil and gas platforms directly — described as a world first.6 The application is narrow, but it suggests the fossil fuel sector is beginning to treat offshore wind as a cost-effective power source for extraction operations, which carries implications for upstream carbon intensity over time.
For the Oga-Katagami-Akita project itself, the generation profile is modest. The project is expected to supply around 35 GWh per year, drawing on renewable electricity from facilities including Shin-Iwaya Wind Park (27MW, Aomori Prefecture), Tsurugamine Wind Farm (7.48MW, Yamagata Prefecture), and Kaze no Mori Oga Wind Farm (4.2MW, Akita Prefecture).5 Twenty-one turbines does not move the needle on Japan's national energy balance. But the choice of equipment does matter for what comes next.
Vestas now has a reference installation outside its traditional European strongholds and outside China's state-supply chain. Other developers scoping Japanese projects will find it easier to specify the same turbine class without carrying the financing penalty attached to unproven deployments. The supply chain implication runs in both directions: Japanese port and vessel infrastructure will need to adapt to handle nacelles and blades at this scale, creating a domestic capability base that feeds future tenders.
Japan's 2030 offshore wind targets imply a multi-gigawatt pipeline that remains largely unfinanced and unpermitted. The Oga-Katagami-Akita project does not resolve that gap. What it does is establish that the equipment and installation expertise for large-scale offshore wind can operate in Japan. Whether the government's revised auction framework generates enough contracted volume, fast enough, to justify the next wave of vessel and port investment is the concrete thing to watch.5,3