Japan aims to award 30 to 45 GW of offshore wind projects by 2040. Yet only one project selected under its national offshore wind law is running: a 16.8 MW floating project off Goto, Nagasaki, since January 2026. This guide covers the four factors that decide that gap (cost, grid, ports and policy) and links to DeepWind’s detailed analysis of each.
The government target counts projects awarded to developers. GWEC’s forecast counts operating capacity: 3.5 GW in Japan by 2030 and 8.4 GW by 2035. Check which number you are using before sizing the market.
Japan’s cost review puts new offshore wind built in 2023 at 30.9 yen/kWh. Round 3’s 3 yen/kWh bids set how much subsidy each project asks for. Returns are meant to come from the power market and long-term offtake contracts.
Fifteen of the 21 promotion and promising zones are in the Hokkaido and Tohoku grid areas. The planned Hokkaido to Honshu subsea link alone carries a 6 to 10 year build time.
What Is Offshore Wind? Why Japan Builds at Sea, and the Fixed vs Floating Choice
An offshore turbine works like an onshore one. The wind turns the blades, and the rotor drives a generator. The reason to go offshore is stronger, steadier wind. Japan’s Energy White Paper 2026 cites global average capacity factors of about 30% onshore and about 40% offshore. Capacity factor is the share of maximum possible output that a turbine actually delivers over a year.
There are two ways to hold a turbine at sea. Fixed-bottom foundations are anchored in the seabed and suit shallow water. Floating platforms carry the turbine on a moored hull and open up deeper water. Japan’s coastal waters are widely described as deepening quickly, so floating wind matters more here than in most markets. The government’s industrial vision targets at least 15 GW of floating projects by 2040.
Turbines keep growing. Japan’s average new turbine rose from 2.0 MW in 2010 to 3.5 MW in 2025, onshore and offshore combined (JWPA). Government port planning now assumes 15 MW units offshore. Larger turbines need heavier vessels and bigger quaysides.
👉 How a Wind Turbine Works: Structure and Output of a 15 MW Offshore Machine
👉 Japan’s Offshore Wind Technology Roadmap 2026: From Coastal Foundations to EEZ Commercialization
How Much Offshore Wind Does Japan Have? 16.8 MW Under the Law, 220 MW in Ports (November 2026)
The policy targets are 10 GW of awarded projects by 2030 and 30 to 45 GW by 2040. An award means a developer has been selected and the project has started development. Operation comes years later.
Sea areas move through three stages. A promotion zone is a sea area where the government has decided to run a developer tender. Promising zones come before that, and preparation zones before those. As of April 2026, MLIT data show 12 promotion zones, 9 promising zones and 17 preparation zones.
Operating capacity is still small. Under the national law, Goto’s 16.8 MW floating project is the only one running. Port areas follow separate rules. There, the 220 MW Hibikinada project in Kitakyushu started operation in March 2026 and is now Japan’s largest offshore wind farm. For scale, all wind power in Japan, onshore included, totalled about 6.4 GW at the end of 2025 (JWPA).
The next wave is Rounds 2 and 3, about 2.9 GW planned to start operation by 2030. Round 1 went the other way. The consortium led by Mitsubishi Corporation announced its exit from three zones, about 1.7 GW, in August 2025. The awards were revoked in September 2025. As of November 8, 2026, the tender guidelines for the re-tender have not been published.
| Figure | What it is | How to read it |
|---|---|---|
| 30 to 45 GW (2040) | Government award target | Counts projects selected for development |
| 8.4 GW (2035) | GWEC operating forecast | Third-party view on a different basis |
| ~2.9 GW (by 2030) | Rounds 2 and 3 planned start-up | The realistic near-term additions |
| 16.8 MW | Operating under the national law | Where Japan stands in November 2026 |
👉 Japan’s 12 Offshore Wind Promotion Zones: Project List and Status (2026)
To see every project on a map, use the Japan Offshore Wind Project Map.
What Does Offshore Wind Cost in Japan? 30.9 Yen per kWh Against a 3 Yen Winning Bid
Japan’s cost figures look far apart until you check what each one measures. The government’s cost review puts new offshore wind built in 2023 at 30.9 yen/kWh. The Japan Wind Power Association (JWPA) puts project cost in the mid-30 yen range. That estimate covers five fixed-bottom projects and includes onshore transmission, grid costs and a 6% project return. The same government paper lists LNG, nuclear and solar between 10 and 20 yen/kWh.
Round 3 winners all bid 3 yen/kWh. Under Japan’s Feed-in Premium (FIP), a top-up paid on the market price, that bid asks for almost no top-up. It does not mean the power costs 3 yen to produce. The developer is betting that wholesale prices and long-term corporate contracts will carry the project.
JWPA’s November 2025 survey puts capital cost at about 908,000 yen/kW and operating cost at about 27,600 yen/kW per year. The same capital cost produces very different costs per kWh from zone to zone. Stronger wind means more output from the same equipment. Deeper water raises foundation cost, and distance from the onshore grid raises transmission cost. DeepWind’s Viability Simulator lets you test those assumptions zone by zone.
Most construction cost is debt-financed, so lenders decide which projects get built. They care less about upside than about whether debt gets repaid in the worst year. That test is the minimum DSCR: cash available for debt service divided by the debt payment due. Under the DeepWind simulator’s criteria, a project is “bankable” when minimum DSCR exceeds 1.35x and equity IRR exceeds 9%. Below 1.20x, financing is difficult. With near-zero subsidy bids, that headroom depends on power prices and offtake terms.
👉 Cost Realities of Japan’s Offshore Wind: LCOE and IRR Across 12 Promotion Zones (2026 Update)
👉 Why Japan’s Offshore Wind Round 1 Ended in Withdrawal
Where Does Japan’s Offshore Wind Get Stuck? 15 of 21 Zones Sit Behind a Northern Grid
Japan’s offshore wind pipeline is concentrated in the north. Fifteen of the 21 promotion and promising zones are in the Hokkaido and Tohoku grid areas. Demand is concentrated around Tokyo. In September 2026, Japan’s grid coordinator OCCTO reviewed its long-term grid plan. It found 6 GW of Hokkaido to Tohoku reinforcement and 8 GW of Tohoku to Tokyo reinforcement the most promising. The Hokkaido to Honshu subsea HVDC link is estimated at 1.5 to 1.8 trillion yen, with a 6 to 10 year build time.
Until the lines are built, curtailment will rise. Curtailment means a grid operator orders plants to cut output because the power cannot be moved. Curtailed power earns nothing, so grid timelines flow straight into project returns.
Ports follow the same logic. Base ports are quaysides designated to store, assemble and load heavy components. Japan designated its first four in September 2020: Noshiro, Akita, Kashima and Kitakyushu. Seven are designated today. For floating wind, MLIT now plans around several ports sharing tasks to meet a two-year installation window (August 2026).
👉 Where Japan’s Offshore Wind Faces Curtailment: Two Grid Areas Carry the FY2031 Congestion Outlook
Can Japan Build 15 GW of Floating Wind When the World Has 278 MW?
Floating wind sets the ceiling for Japan’s long-term growth. Globally, it is still a small industry. GWEC counts 278 MW of floating capacity worldwide at the end of 2025, and no new floating project started operation that year. Japan’s 2040 goal of 15 GW is roughly 50 times today’s global fleet.
The government plans to scale in steps. A July 2026 Agency for Natural Resources and Energy paper schedules deep-water, harsh-sea demonstrations for 2027 to 2032. It also considers a mid-scale demonstration of about 300 MW as a bridge to commercial projects. The open question is whether ports, vessels and component supply can scale at the same pace as the technology.
How Japan Picks Developers: The 2026 Law Change, the EEZ and Price Floors
Japan’s offshore wind law was amended with effect from April 1, 2026, and given a new title. The amendment extends the regime beyond territorial waters into the exclusive economic zone (EEZ). Deep-water sites suited to floating wind now have a legal route to development.
Developer selection is changing too. After the Round 1 exit, the June 2026 revision of the operating guidelines introduced what works as a price floor. The design now gives more weight to whether a bidder can actually finish the project. On revenue, the open question is how far offshore wind can use the Long-Term Decarbonization Auction (LTDA). The LTDA lets a plant recover fixed costs through long-term capacity payments.
Japan’s offshore wind market has moved past proving the technology. The live question is who carries the risk, and at what price.
Round 1’s exit and Round 3’s 3 yen bids come back to one question: who pays when inflation and interest rates rise. Price-based tenders put that cost on developers. Round 1 reads as a case where the developer could not absorb it. Round 3 bidders chose to recover their costs from the market, with almost no subsidy. The 2026 guideline revision reads as a step toward moving some of that cost back to the state.
That shifts which numbers matter. Watch three: the terms of the Round 1 re-tender, the timing of Round 4, and the build schedules for northern grid links and ports. Each decides when and on what terms capacity arrives, ahead of how many gigawatts eventually get built. Developers, contractors and lenders will all be pricing these three signals.
Frequently Asked Questions
Related DeepWind Articles
- How to Read Japan’s Offshore Wind Market: Investment, Cost, and Supply-Chain Constraints
- Japan Offshore Wind Cost Structure and Economics: Four Numbers That Decide Viability
- Japan FIT vs FIP: How Offshore Wind Revenue Works and What a ¥3 Bid Means
- DeepWind Viability Simulator: LCOE and IRR by zone
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