Japan’s Goto floating wind farm (16.8MW) started operating in January 2026 on a fixed tariff of JPY 36/kWh, and its construction cost has never been published. Working back from revenue, 20 years at that tariff can repay about JPY 530,000 to 1.18 million per kW (DeepWind calculation). That range shows how far Goto’s numbers can guide cost estimates for later floating projects.
Output and cost of capital move it from about JPY 530,000 to 1.18 million per kW, or roughly JPY 8.9 to 19.9 billion for the whole 16.8MW. At JPY 50,000/kW/year for operations and maintenance, the range falls to about JPY 390,000 to 970,000.
Two demonstration projects averaged JPY 2.056 million per kW in government cost reports. The projects are unnamed, so this cannot be read as Goto’s cost. It is still one of the few actual data points for small-scale floating wind.
Construction cost, actual output, loan terms, and who paid to rebuild the floaters are all undisclosed. What can be shown is the condition: what the JPY 36 revenue needs in order to recover the investment.
👉 Background: floating offshore wind in Japan
| Project | Goto City offshore wind project (Nagasaki, off the east side of Fukue Island) |
|---|---|
| Status | Operating since 5 January 2026 (originally planned for January 2024) |
| Size | 16.8MW (8 × Hitachi 2.1MW) |
| Foundation | Hybrid spar (steel upper section, concrete lower section), three-point mooring |
| Developer | Goto Floating Wind Farm LLC (Toda Corporation, ENEOS Renewable Energy, Osaka Gas, INPEX, Kansai Electric Power, Chubu Electric Power) |
| Revenue | JPY 36/kWh under the feed-in tariff (FIT), for 20 years |
| Construction cost | Not disclosed |
The project page covers the timeline and environmental assessment. This article deals only with cost.
👉 Goto City Offshore Floating Wind Power Project
Revenue at JPY 36: About JPY 87,000 to 115,000 per kW a Year
The revenue side can be worked out from public numbers, because the price is fixed. The remaining unknown is output. It is measured by capacity factor (CF): actual generation as a share of full-power output all year.
Goto’s actual output has not been published, so the table uses three values from Japanese government documents.
| CF | Where the value comes from | JPY/kW/year | 16.8MW, per year |
|---|---|---|---|
| 27.7% | Average of six reported projects, demonstration units included | 87,357 | JPY 1.47 billion |
| 32% | Developer survey by the Japan Wind Power Association (JWPA) | 100,915 | JPY 1.70 billion |
| 36.6% | Average used to set price caps for Rounds 2 and 3 | 115,419 | JPY 1.94 billion |
Subtract yearly operations and maintenance (O&M) from that revenue, and what remains can repay construction. Government cost reports show O&M averaging JPY 36,000/kW/year across four commercial projects and JPY 50,000 across two demonstration projects. At 32% CF and the commercial figure, JPY 64,900/kW/year is left over, or about JPY 1.09 billion a year for the whole farm.
Twenty Years Can Repay JPY 530,000 to 1.18 Million per kW
Construction is paid for up front and recovered from sales over 20 years. The return demanded on that capital, known as the cost of capital, therefore sets how much can be repaid. The table below works backward with O&M at JPY 36,000.
| Discount rate | CF 27.7% | CF 32% | CF 36.6% |
|---|---|---|---|
| 3% (government cost review) | 764 | 966 | 1,182 |
| 6% (JWPA project IRR) | 589 | 745 | 911 |
| 7.3% (IRENA WACC for Japan offshore) | 532 | 672 | 822 |
With O&M at the demonstration figure of JPY 50,000, the range falls to about JPY 390,000 to 970,000. Goto maintains eight moored turbines at sea, and only operating data will show which figure is closer. To test other assumptions, use the DeepWind Simulator.
The start of the 20 years also matters. The 2022 project plan set out 20 years of FIT sales and a shutdown at the end of December 2043. The developer’s schedule places the start of the certified period at the original operation date, January 2024. The documents reviewed do not say whether the delay moved that period. If sales ran for 18 years, the JPY 966,000 at 3% and 32% CF would fall to JPY 893,000.
JPY 2.056 Million vs JPY 779,000: Neither Can Be Read as Goto’s Cost
The natural comparison is the cost actually reported to the government. The reports show JPY 2.056 million per kW on average for two demonstration projects and JPY 779,000 for four commercial projects. The repayable range covers the commercial average and stops well short of the demonstration average.
The documents do not name the six projects, or say whether Goto is among them, so JPY 2.056 million cannot be treated as Goto’s cost. The cost model from NEDO, Japan’s state energy technology agency, gives JPY 570,000 per kW for a spar (2023 exchange rates). A model assumption and a reported cost are different things, though. The next article compares them in more detail.
👉 Floating Offshore Wind Cost Structure and LCOE Reality
Scale probably matters too. Goto’s 16.8MW is little more than the output of one 15MW turbine. Yet it takes eight floaters, 24 mooring chains, and cable connections to eight units. In DeepWind’s view, this tends to raise the cost per kW compared with projects using large turbines, so Goto’s costs are unlikely to carry over directly.
Four Choices at Goto That Shaped the Cost
The amounts are undisclosed, but the developer’s documents show where the money went.
| Stage | What Goto did |
|---|---|
| Floater construction | The lower section is concrete, cast as rings at a yard in Fukue Port. Steel sections went to ironworks and shipyards in Nagasaki Prefecture. The developer cites better volume production and local builders as the benefits |
| Quay and port | Floaters are built lying flat, which spreads the weight and allows work on a quay with weak ground, the developer says. The plan used local floating cranes of 200 to 500 tonnes for cargo handling |
| Assembly at sea | Floaters were raised upright in the sheltered waters north of Kaba Island, where the turbines were assembled, then towed to site. Draft is 76m, and the developer’s drawing shows 100m of water at site |
| Removal | The plan reverses the installation steps. This cost is left out of the table above |
Some costs were never in the plan. A defect found during floater production pushed the start of operation back two years. One installed floater was then brought ashore and inspected. Long-term integrity proved hard to assure, and in January 2024 the developer decided to bring all three ashore and rebuild them. Neither the cost nor who bore it has been disclosed.
On a fixed tariff, the revenue ceiling comes first. No document reviewed shows the JPY 36 changing as costs rose, and among selected projects, the price adjustment scheme is expected to help only Saikai-Enoshima. Any lenders would watch the debt service coverage ratio (DSCR), which shows how many times available cash covers repayments. Goto’s loan terms are undisclosed. From outside, the check stops at a ceiling: at 32% CF, about JPY 1.09 billion a year is available for debt and dividends.
Goto’s JPY 36 is not a benchmark for floating wind. It is the price attached to a first project of eight small turbines.
Goto is the first plant to operate in a zone under the Marine Renewable Energy Act, and Japan’s first commercial multi-turbine floating farm. That makes its tariff and its two-year delay easy to cite as references for later projects. As shown above, though, the cost that tariff can repay spans a wide range, and the actual cost remains unknown. There is not yet enough public evidence to say from outside whether the project pays.
Operating results are what will start to matter. Whether first-year output lands nearer 27.7% or 36.6% changes how to read the table, and O&M near JPY 36,000 or JPY 50,000 matters about as much. Both may emerge gradually through cost reports and council documents.
Anyone estimating costs for later floating projects should be careful about using Goto’s numbers directly. Moving from 2.1MW to 15MW turbines changes both the cost mix and the construction method. The two years lost to rebuilding and the practice of assembling in sheltered water do transfer. The listing of the nearby Goto South area as a Preparation Zone is the next thing to watch.
Related DeepWind Articles
- Goto City Offshore Floating Wind Power Project
- Floating Offshore Wind Cost Structure and LCOE Reality
- Japan Offshore Wind Cost Structure and Economics: Four Numbers That Decide Viability
- Floating Offshore Wind Platform Types
- Japan FIT vs FIP: How Offshore Wind Revenue Works
Free reportWhich of April’s planning assumptions no longer hold? Our 17-page review of Japan’s offshore wind market, April to September 2026. Free when you subscribe to the Weekly. See what’s inside →