Published: August 12, 2025 | Updated: July 31, 2026
FLOATING WIND
On 15 July 2026, Japan’s Agency for Natural Resources and Energy asked its prefectures to nominate a sea area for a floating wind demonstration, with submissions closing on 30 October. The criteria are the substance. A candidate area must contain water at least 500 metres deep, hold an annual mean wind speed of 8.5 m/s or more across most of it, and have a seabed that is partly or wholly bedrock. It must also sit beside roughly 50 square kilometres capable of hosting about 240 MW within a few years. That last condition is the one that changes what this programme is: not a test site, but a commercial zone that starts as a demonstration.
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Deep water, bedrock, steep gradients and high waves appear in the criteria as things the site should have. A programme built to prove technology for the EEZ and for export cannot learn what it needs from easy water, so it is asking for the difficult kind on purpose.
The requirement for an adjacent 240 MW area, with promotion zone designation envisaged beyond it, means selection is not only about research value. The 2025 policy paper says the same thing in plain terms. Prefectures are being asked to nominate the seed of a future commercial zone.
Japan currently negotiates a sea area project by project, which the ministry itself identifies as a constraint compared with Europe’s standing test sites. Criterion seven, requiring part of the area to serve long term as a test centre, is an attempt to fix that structurally rather than one project at a time.
What the July 2026 Request for Information Asks For
The instrument matters. This is a request for information addressed to prefectures, not an open tender to developers. Prefectures submit what they know about candidate waters, the national government selects the candidate area, and a separate competitive process for the demonstrator follows afterwards. It is also distinct from the annual information request run under the Renewable Energy Sea Area Utilisation Act, a point the document makes explicitly.
Nine conditions are mandatory. The physical ones define the site.
| Mandatory condition | Requirement |
|---|---|
| Water depth | Must contain an area at least 500 m deep, large enough for about two turbines. Remaining area preferably 100 to 500 m |
| Wind resource | Annual mean wind speed of 8.5 m/s or more across most of the area |
| Seabed geology | Partly or wholly bedrock |
| Area | Large enough for five or more turbines |
| Tenure | Occupancy permitted for longer than a few years |
| Test centre | Part of the area usable long term as a test centre |
| Adjacent expansion | About 50 km² able to host roughly 240 MW, secured within a few years |
| Future zoning | Promotion zone designation envisaged for waters adjacent to the expanded area |
| Stakeholder consent | Understanding obtained from parties requiring operational coordination |
Three further conditions are listed as desirable rather than mandatory: periods with significant wave heights above 1.5 to 2.0 metres, periods with wave periods beyond 9 seconds, and steep seabed gradients. Read as a set, the criteria describe a site that most developers would ordinarily try to avoid.
The prefecture’s own commitment is part of the deal. Its fisheries, shipping and environmental bureaus must take responsibility for identifying and coordinating affected parties, and must grant the sea area occupancy permit under prefectural ordinance if a demonstrator is selected. Nominating a site is therefore an administrative undertaking, not a suggestion.
How This Compares With the Two Demonstrations Already Running
Japan already has two floating demonstrations under the Green Innovation Fund’s Phase 2, off southern Akita and off Tahara and Toyohashi in Aichi. Setting their published characteristics beside the new criteria shows how much the bar moves.
| Southern Akita (existing) | Aichi (existing) | New criteria | |
|---|---|---|---|
| Water depth | About 400 m | About 80 to 130 m | Must include 500 m or deeper |
| Wind speed | 7.5 to 8.0 m/s | 8.5 to 9.0 m/s | 8.5 m/s or more across most of area |
| Seabed geology | Almost entirely sand, gravel and mud | Pliocene to mid-Pleistocene strata, normal faulting | Partly or wholly bedrock |
| Seabed topography | Flat | Continental shelf | Steep gradient desirable |
| Wave height | About 1.2 to 1.4 m | About 1.0 to 1.2 m | Hs above 1.5 to 2.0 m desirable |
| Area | About 30 km² | About 13.06 km² | Five or more turbines, plus 50 km² adjacent |
Akita is already in 400 metres of water, which by international standards is deep. What changes is everything underneath and around it. Flat sand becomes bedrock on a slope, and a moderate wind resource becomes a strong one. Anchoring is where those differences concentrate: the 2025 policy paper notes that steep terrain tends to come with rock, and that rock requires pile anchors rather than the drag embedment types suited to sand.
Why the Criteria Look Like This
The shape of the criteria follows from Japan’s resource geography. The ministry’s own assessment is blunt about it: where the wind potential is greatest, bedrock is also widespread, and high waves, steep gradients and deep water come with it. Japan cannot choose between good wind and difficult ground, because in its waters they are the same places.
The programme’s stated purpose reinforces this. The demonstration is intended to support expansion into the exclusive economic zone, opened to offshore wind installation by the June 2025 amendment to the Renewable Energy Sea Area Utilisation Act, and to build technology exportable to the Asia-Pacific region, where conditions resemble Japan’s and where the offshore wind market is projected to become the world’s largest. The 2025 paper describes the exercise as one for which no international precedent exists.
There is also a numerical driver behind the urgency. Against a target of 30 to 45 GW of projects formed by 2040, ten promotion zones have been awarded, amounting to roughly 4.6 GW, or 5.1 GW including port areas, and almost all of it fixed-bottom. A further 25 areas sit in the promising and preparatory categories. Floating wind is where the remaining distance has to be covered, and most of Japan’s floating resource is in water that the existing demonstrations do not represent.
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Criterion Eight and What It Says About Intent
The mandatory conditions include one that has little to do with research. The candidate area must sit next to roughly 50 square kilometres capable of hosting about 240 MW within a few years, and a further condition asks that promotion zone designation be envisaged for waters adjacent to that expanded area.
This is not an inference from the procurement document alone. The 2025 policy paper states that the selection is to be made with the aim of promotion zone designation in surrounding waters, and that the design should allow the area to remain usable for demonstration into the future rather than serving a single unit. The demonstration is the first step of a build-out that is already anticipated in the policy.
For a prefecture, that changes the calculation. Nominating an area is not offering a research site for a few years. It is proposing where a commercial zone should eventually be, and accepting the coordination burden that comes with it from the start.
A demonstration site with long-term tenure changes the financing question for the concepts that use it. Technology readiness feeds cost of capital and insurance terms as well as debt sizing, and the step that thins the field is the move from tank testing to a full-scale prototype operating offshore, which needs a site, a turbine supplier and an offtaker at the same moment. A standing test area with secured occupancy removes one of those from the critical path for every concept that follows, which is a different kind of subsidy from a capital grant and a more durable one.
The Constraint the Programme Is Trying to Fix
The most candid passage in the 2025 paper is about process rather than engineering. Japan negotiates a sea area separately for each demonstration project, while European developers advance technology verification quickly at established test sites. With concrete floaters and TLP designs now seeking verification and the number of players increasing, the paper concludes that Japan needs more demonstration opportunities and faster ones, and that a test site should be developed.
Criterion seven follows directly from that diagnosis. Requiring part of the candidate area to be usable long term as a test centre is an attempt to convert a recurring negotiation into standing infrastructure. Whether it succeeds depends less on the criteria than on what a prefecture is willing to commit to, which is why the administrative obligations attached to nomination are as significant as the physical thresholds.
What this does not resolve is the layer below. Installing in deep water on rock requires anchoring, cable and marine construction methods that are themselves still being developed, and Japan’s Ports and Harbours Bureau selected seven research projects in July 2026 covering exactly that ground, with six running to FY2028.
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The site criteria and the construction methods are on different clocks. A candidate area is due to be selected from submissions closing in October 2026, while much of the marine construction research it will depend on runs to FY2028. Pile anchoring on steep rock, dynamic cabling at depth and weather-window management in higher seas are the specific gaps. Developers assessing this programme should treat the demonstrator selection date and the maturity date of the methods as separate variables rather than assuming they converge.
What Happens Next, and the 300 MW Step After It
Submissions close on 30 October 2026. The national government then selects the candidate area, and a competitive process for the demonstrator follows. Area names are not published at the information-provision stage and will only be disclosed once an area is selected, together with its size, position and natural conditions, which means public speculation about which waters are in play should be treated as speculation.
A report to the renewable energy subcommittee on 28 July 2026 put dates and a sequence around the programme for the first time. The deep-water and harsh-conditions demonstration is scheduled for 2027 to 2032 and will use full-scale turbines rather than reduced models, with deployment to Asia-Pacific waters of similar conditions explicitly in view. Running alongside it, the government intends Japanese companies to be involved in 30 GW of overseas projects by 2040, treating participation in foreign demonstrations, particularly in the UK, as a way to accumulate knowledge usable at home.
The step that matters most for the argument here comes after. Depending on progress and market conditions, the agency is considering assembling a mid-scale demonstration of about 300 MW as a bridge to commercialisation. Set that beside the requirement that a candidate area sit next to roughly 240 MW of expansion capacity, and the escalation is visible in full: a harsh-conditions demonstration through 2032, a mid-scale project in the hundreds of megawatts, then commercial zones. The site being selected this year is the first rung.
Hokkaido’s governor has said publicly that the prefecture should respond actively. That is a statement of intent from one prefecture, not a filing, and the same document that sets the criteria also sets the confidentiality.
Japan is not procuring a test site. It is procuring the first deepwater commercial zone, and calling it a demonstration.
Read only the physical thresholds and this looks like a research programme with unusually demanding specifications. Read criterion eight alongside the 2025 policy paper and it reads differently. The area must be adjacent to 240 MW of expansion capacity, promotion zone designation is envisaged beyond that, and the site is meant to remain usable for demonstration indefinitely. The demonstration is the entry point to a build-out that has already been sketched.
That framing explains why the burden falls on prefectures rather than developers. What is scarce here is not engineering capability but a stretch of difficult water where fisheries, shipping and environmental coordination have already been settled, with tenure long enough for a technology to prove itself and a neighbouring area available when it does. Only a prefecture can assemble that, and the criteria make its bureaus responsible for holding it together.
The open question is timing rather than intent. The site is selected in 2026, while the anchoring, cabling and marine construction methods it depends on are funded to 2028. Japan has chosen to secure the ground first and mature the methods afterwards. That is a defensible sequence when the ground is the scarce item, but it means the demonstration’s schedule will be set by the slowest of those methods, not by the date the area is chosen.
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