Japan's Offshore Wind Regulatory Framework
Legal Framework, Auction Reform, and Recurring Sources of Issues in Project Development and Operations

Executive Summary

Japan has, in a comparatively short span, assembled the legal and regulatory framework of an offshore wind regime: a dedicated sea-area licensing statute, a government-led promotion zone and auction system, a revenue-support scheme that has migrated from feed-in tariff to feed-in premium and, most recently, to a capacity-based long-term decarbonization auction, and, with effect from 1 April 2026, a two-stage permitting track extending the regime into the Exclusive Economic Zone for floating wind. On paper, the rules that market participants most need are now in place.

The practical experience of Rounds 1 through 3, however, shows that the existence of a framework does not by itself resolve execution risk. The withdrawal of the Mitsubishi-led consortium from three Round 1 projects in August 2025, following its unusually low winning bids in 2021 and a subsequent doubling of construction costs, has forced the government into a sustained cycle of auction reform, price-adjustment mechanisms, lease-term extensions, and port and grid support measures, the auction-design core of which was finalized in the June 2026 revision of the auction operation guideline, while other supporting measures remain under discussion as this briefing goes to print.

This briefing addresses issues relevant to developers, their lenders, and the turbine, foundation, and balance-of-plant (BOP) contractors executing the projects, including an overarching contract-structuring issue, the absence of a single wrap contractor. It sets out (I) the legal and institutional framework governing offshore wind in Japan; (II) the auction and revenue-support system and its 2025–2026 reform trajectory; (III) recurring issues encountered during project development, including fisheries relations, environmental assessment, port access, and shipping-lane coordination; and (IV) recurring issues encountered during construction and operations, including cost-inflation risk allocation, decommissioning, curtailment, and dispute-resolution planning.

I. Legal and Institutional Framework

 1. The Dual-Track Statutory Basis

Japan regulates offshore wind siting through two statutory tracks, depending on whether a site falls within a port area or outside it, each with its own statutory basis and regulator.

Offshore wind facilities sited within port areas are governed by the 2016 amendments to the Ports and Harbours Act, which introduced long-term occupation rights allocated by auction. Facilities sited in the “general sea area”, territorial and inland waters outside port areas, fall instead under the Act on Promoting the Utilization of Sea Areas for the Development of Marine Renewable Energy Power Generation Facilities (the “Sea Area Utilization Act”), enacted in 2018. Under the Sea Area Utilization Act, the Ministry of Economy, Trade and Industry (METI) and the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) jointly designate “Promotion Zones,” occupation rights over which are then allocated to developers through a competitive public auction.

A June 2025 amendment to the Sea Area Utilization Act, retitling the statute the Act on the Development of Marine Renewable Energy Power Generation Facilities and taking effect on 1 April 2026, extends the regime for the first time into Japan's Exclusive Economic Zone (EEZ). Because most of Japan's EEZ seabed lies at depths unsuited to fixed-bottom foundations, the EEZ track is designed principally around floating wind technology and adopts a two-stage permitting sequence, in contrast to the single-stage process used for territorial and inland waters: (1) a provisional permit stage, followed by refinement of the zone map and installation plan in consultation with a statutory council, and (2) a subsequent application for a final installation permit.

2. Key Institutional Actors and Their Roles

A structural feature worth flagging to clients unfamiliar with the regime: a provisional permit under Article34 (the EEZ track) is not a final entitlement. METI and MLIT then organize the statutory council under Article 36, in which the provisionally approved operator participates, and if the operator’s draft zone map or installation plan is inconsistent with the matters agreed upon by the council, the operator is obliged to revise it accordingly before a final installation permit will issue. This creates a meaningful post-award renegotiation window that is not always priced into early-stage project schedules.

Notably, the amended statute does not itself restrict foreign participation or foreign capital in Promotion Zone auctions, although general controls under the Foreign Exchange and Foreign Trade Act may still apply to particular transactions.

II. Auctions and Revenue Support: A System in Active Reform

1. From FIT to FIP to LTDA

In brief, under a feed-in tariff (FIT), the project is paid a fixed price for each kilowatt-hour it generates, regardless of where market prices move. Under a feed-in premium (FIP), the project instead sells its electricity into the wholesale market and receives a top-up (“premium”) added to the market price, so revenue rises and falls with the market. The Long-Term Decarbonization Power Source Auction (LTDA) works differently: rather than paying for the electricity generated, it pays a fixed annual amount per kilowatt of capacity for 20 years. In exchange, most of the revenue the project earns in the market must be paid back to the scheme administrator, a “clawback” that prevents the project being paid twice for the same output. This is why LTDA functions as a cost-recovery mechanism rather than a profit-guarantee one.

Round 1 (awarded 2021) operated under FIT. Rounds 2 and 3 shifted to FIP, exposing projects to market price risk in exchange for potential upside. However, Round 3 bids came in at an effective zero premium, leaving revenue dependent almost entirely on wholesale price capture.

Because zero-premium FIP alone does not support conventional project-finance debt coverage ratios, the government has since introduced a transitional mechanism allowing Round 2 and Round 3 projects to participate in the LTDA. As explained above, those market-derived earnings must be paid back under the clawback at tiered rates of 85 to 95 percent depending on the amount, narrowing the revenue variance that lenders must underwrite. Under the draft FY2026 LTDA auction guidelines published in June 2026, participation requires the project to amend its supply price under the occupancy plan to zero and forgo FIP premium payments (including the balancing-cost portion), so that fixed costs are not recovered twice. LTDA eligibility for offshore wind is, at present, limited to Round 2 and Round 3 as a time-bound exception; Round 4 onward is excluded from this transitional route by design.

2. The Round 1 Withdrawal and Its Downstream Effects

In August 2025, the Mitsubishi-led consortium withdrew from all three of its Round 1 awards, off Akita and Chiba prefectures, totaling 1.7 GW, after construction costs more than doubled against a bid struck in 2021 at levels well below the government's price ceiling and below competing bids. Mitsubishi had already recognized an impairment loss of JPY 52.2 billion in its FY2024 results, and indicated at the time of withdrawal that additional losses would be limited.
The withdrawal has become the reference event around which the current cycle of auction, port, and offtake reform is being organized.

In response, METI and MLIT have advanced a package of reforms, the auction-design core of which was finalized in the June 2026 revision of the operational guideline for general sea area auctions: introduction of an “expected supply price band” beneath the price ceiling, with a flat maximum price score (120 points) for bids at or below the ceiling minus the band, to prevent unrealistically low bids from prevailing on price score alone; rebalanced scoring in which project-feasibility points (120 points, equal to price) are built up from detailed check items rewarding supply-chain formation and executable planning, with the weighting for speed halved to 10 points and converted to a relative evaluation; renewal of the sea-area occupancy permit beyond the initial maximum 30-year term as a general rule, subject to conditions, in recognition that permitting and construction alone can consume 6 to 8 years before commercial operation begins; tightened withdrawal rules endorsed by the METI–MLIT joint committee, exclusion of a withdrawing developer from the following auction (with extension to affiliated group companies under consideration for future rounds), and free provision of seabed and other survey data to re-auction participants, to be implemented through individual auction guidelines; and a re-auction of the vacated Akita and Chiba sites under the revised criteria. The Round 4 auction, originally intended to proceed on an annual cadence, was itself postponed to allow this reform process to conclude.

On the question of retroactive inflation relief, the government's position has been consistent and should be conveyed clearly to clients: requests from Round 2 and Round 3 developers to have historical inflation (from bid date to present) reflected in pricing have been declined. The cost-adjustment mechanisms under discussion apply only prospectively, to future cost increases, on the stated rationale that retroactive adjustment would alter the competitive assumptions on which the original auction outcome was based.

3. Securing Offtake: PPA Risk Under Zero-Premium FIP

With Round 3 awarded at an effective zero premium, project revenue depends on the sponsor’s ability to secure long-term offtake, through corporate PPAs or sales arrangements with retailers, rather than on statutory support. The government’s own analysis of the Round 1 withdrawal acknowledged the difficulty of securing offtakers able to commit to long-term PPAs at price levels sufficient to absorb recent cost increases. Japan’s corporate PPA market remains shallow relative to project sizes of several hundred megawatts: few domestic offtakers can absorb such volumes over long tenors at acceptable credit quality, and lenders will size debt against contracted rather than merchant revenue, so uncontracted capacity directly reduces leverage. The LTDA route mitigates this only for Rounds 2 and 3. Round 4 bidders and their contractors should therefore treat offtake strategy as a core bid-stage workstream, addressing offtaker creditworthiness, the treatment of non-fossil certificates, curtailment risk allocation, and price-floor mechanics within the PPA itself. Recent reports of a foreign sponsor reconsidering its position in a Round 3 project illustrate that an auction award without bankable offtake does not yet amount to a financeable project.

III. Recurring Issues in Project Development

Here are key issues recurring in project development that affect developers as well as the contractors and suppliers bidding into their supply chains:

Fisheries rights and compensation

Fishing rights in Japan are proprietary rights under the Fisheries Act. A local fisheries cooperative whose operations are interfered with by an offshore wind project may seek injunctive relief or indemnities against the developer. Because these are property rights rather than mere consultative interests, developers are well advised to enter into negotiated compensation agreements with affected cooperatives proactively. Disputes over the adequacy or scope of such agreements remain one of the most common friction points during the pre-construction phase. Consequently, fisheries compensation disputes commonly surface as schedule delay claims under the affected contractors’ package contract.

Environmental assessment consolidation

Under the pre-2025 framework, environmental impact assessment was conducted individually by each developer, which in practice meant multiple competing developers running parallel scoping and methodology studies over the same candidate area before a Promotion Zone was even designated, a source of considerable local confusion and community fatigue. Under the amended Sea Area Utilization Act (effective April 2026), for Promotion Zones in territorial and internal waters, the Ministry of the Environment now conducts the marine environmental survey itself, ahead of zone designation, through a single government-led process involving a publicly disclosed draft methodology, explanatory meetings, and consultation with relevant local governments. This should reduce duplicated diligence costs for developers bidding into future rounds, though it also means developers have less direct control over survey scope and timing. For the EEZ, a separate pre-designation survey process applies under Article 32, combining a METI survey of the zone with an MOE survey of marine environmental information, the results of which are published.

Port access: the “software” layer

Public debate over base port capacity has traditionally focused on physical constraints such as quay length, water depth, ground-bearing capacity. For developers, their lenders, and the contractors mobilizing to that port, however, the contractual terms governing port use have often proven the more material constraint: the size of contract guarantees required of the first developer to use a given port, the timing of lease-fee obligations relative to commercial operation, and restoration obligations attaching to privately funded port upgrades such as ground reinforcement. Through its study group on ports for the promotion of offshore wind, most recently in March 2026, MLIT put forward proposals to ease each of these: reducing the guarantee burden on first-mover developers, introducing a lease-fee suppression period prior to commercial operation, and relaxing restoration obligations for privately funded improvements. These remain proposals under review rather than settled rules, and should be tracked closely by any developer structuring port-use agreements in the near term.

Other siting constraints: shipping lanes and defense

As projects have moved into open-sea areas with meaningful vessel traffic, MLIT issued an administrative circular to the relevant prefectures and agencies on 24 March 2026 establishing a turbine-to-shipping-lane setback framework for open water, since folded into the Promotion Zone Designation Guideline; developers with sites near established routes should expect effects on turbine layout and, in some cases, project capacity. Separately, in strategically sensitive sea areas, the Round 3 Aomori zone being the most prominent example, bid rules require consultation with the Ministry of Defense and certification that the project will not interfere with Self-Defense Force or allied force activity, a step best built into the project timeline from the outset.

Contract structure: the absence of an EPC wrap

Japanese offshore wind projects are rarely executed under a single EPC wrap. Turbine suppliers, limited in number and themselves still new entrants to Japan, have consistently declined whole-plant completion exposure or interface risk with BOP, foundation, and marine works. Instead, the project company contracts directly with each major package contractor, and interface risk between packages sits with the project company itself. This affects financing (no single point of completion responsibility for lenders to rely on), dispute allocation (a defect at a package boundary requires the project company to determine which contractor is responsible), and drafting (aligning warranties and interface risk across multiple, unrelated contracts). Multi-package interface allocation should be treated as a first-order issue when structuring these contracts, whether from the project company's side or an individual contractor's.

IV. Recurring Issues in Construction and Operations

Cost inflation and bid discipline

The central lesson of Round 1 is that Japan's auction design has, to date, allocated inflation and supply-chain risk to the developer for the life of the fixed-price or premium period, with no retroactive adjustment mechanism. Those structuring construction packages and turbine supply arrangements for Japanese offshore projects should assume that price-review or hardship clauses within those private contracts, rather than the public auction terms, are the primary lever available to redistribute this risk, and should scrutinize them accordingly.

Turbine supply and technology substitution

Extended permitting and construction timelines have exposed projects to turbine discontinuation risk: one Round 2 project consortium announced in January 2026 that its originally specified 18 MW turbines had been discontinued by the manufacturer and presented a revised plan based on a larger number of smaller 15 MW-class units, with the final turbine model to be determined following discussions with manufacturers. The government has responded by allowing greater flexibility for developers to change turbine suppliers post-award. This flexibility should be reflected in the relevant contract documentation, since it functions as a two-way relief valve: it protects developers from change-of-scope claims under the turbine and BOP contracts, but conversely turbine and BOP contractors should also want it documented, as it is their scope and price that shift.

Curtailment and grid constraints

Grid capacity and dispatch curtailment remain identified industry-wide as unresolved bottlenecks affecting bankability, alongside certification transparency and supply-chain visibility. Industry bodies have called for compensation mechanisms tied to curtailment and for a shift toward commercial-operation-date-based targets rather than pipeline-formation targets, on the view that this would better align government objectives with actual project delivery incentives. No binding curtailment compensation regime is yet in place, and this should be flagged as an open risk in financing and offtake discussions.

Occupation term and decommissioning

Occupation periods under the first three auction rounds were structured around a 30-year total term, calculated to allow for 4 to 5 years of environmental assessment, 2 to 3 years of construction, roughly 20 years of operation, and 2 years for decommissioning, with removal and re-bidding required at term end. Under the June 2026 revision of the operational guideline, renewal of the sea-area occupancy permission following expiry of the initial validity period of the certified occupancy plan is now permitted as a general rule, provided that the zone remains appropriately designated, continued operation by the incumbent is rational from the standpoint of stable and economical electricity supply, and the operator satisfies the permit review standards; the auction guidelines for the existing Round 1–3 sites are expected to be aligned accordingly. Decommissioning plans, submitted as part of the original business plan, must comply with the Waste Management and Public Cleansing Act and the Act on Prevention of Marine Pollution and Maritime Disaster; any partial in-situ disposal of facility components requires separate Ministry of the Environment approval. Developers should confirm decommissioning cost provisioning is calibrated to the full term, including the possibility that renewal is not granted.

Carbon and disclosure obligations

Operators and their corporate parents should also track the amended GX Promotion Act, under which participation in Japan's emissions trading system (GX-ETS) becomes mandatory from 1 April 2026 for businesses whose average annual CO₂ emissions over the preceding three fiscal years reach 100,000 tons or more (measured on direct emissions), with the first allocations of emissions allowances and trading commencing from FY2027. This is more likely to be relevant to a developer's broader corporate group than to the offshore wind special-purpose vehicle itself, but should be checked at the group level.

V. Dispute Resolution and Practical Recommendations

Disputes arising from Japanese offshore wind projects tend to cluster around a small number of recurring fact patterns: (a) fisheries compensation adequacy and scope; (b) cost-overrun and hardship allocation between the auction-fixed public price and privately negotiated construction package and turbine supply terms; (c) turbine substitution and specification-change claims; (d) port-use guarantee, restoration, and lease-fee disputes; and (e) withdrawal, penalty, and step-in rights following a developer's decision (or a lender's insistence) not to proceed. Given the mixed public-law/private-contract character of the regime, well-drafted project documents should distinguish clearly between risks allocated by statute or auction rule (generally non-negotiable and, per the government's stated position, non-retroactive) and risks properly addressed through commercial contract terms. For the latter, arbitration (JCAA, SIAC or ICC, depending on the parties and financing sources) remains the more practical forum; the statutory council process is designed for stakeholder deliberation, not binding adjudication.

Given the pace of reform since August 2025, clients should treat any auction rule, port guideline, or lease-term summary as provisional pending the government's finalization of the remaining items of the current reform package (in particular the port-use and offtake-related measures), and should confirm current terms before relying on them in bid, financing, or contract negotiations.

A Market Still Building Its Own Experience Base

Worth noting candidly for those comparing Japan to more established offshore wind markets: much of the risk allocated on paper in mature markets is, in practice, absorbed through judgment and working relationships built up between repeat counterparties, not solely through contract enforcement. That shared experience base doesn't yet exist in Japan. Offshore wind is a young industry here, and project teams (developers, contractors, and turbine suppliers alike) often have limited experience working with foreign counterparties. This reflects the industry's youth, not any deficiency in the participants, but it means the gap between a well-drafted contract and a well-executed project is currently wider here. Language differences compound this, as do gaps in escalation practices, decision-making cadence, and change-management expectations. Closing this gap takes deliberate effort from both sides, a real project cost that developers and contractors alike should budget for.

Resouces

Act on the Development of Marine Renewable Energy Power Generation Facilities (Act No. 89 of 2018, as amended June 2025; effective 1 April 2026), e-Gov (in Japanese)
METI, press release on cabinet approval of the amendment bill (7 March 2025, in Japanese)
METI Agency for Natural Resources and Energy and MLIT Ports and Harbours Bureau "New auction framework to ensure completion of offshore wind projects", joint meeting of the Offshore Wind Promotion Working Group and Offshore Wind Promotion Subcommittee, Material 1 (21 January 2026, in Japanese)
METI ANRE and MLIT, “Business environment measures and new auction framework for completing offshore wind projects” (27 November 2025, in Japanese)
Mitsubishi Corporation, news release on the re-evaluation of its domestic offshore wind projects (27 August 2025, in Japanese)
MLIT Ports and Harbours Bureau, administrative circular on separation distances between offshore wind facilities and heavily trafficked sea areas (24 March 2026, in Japanese)
METI, GX emissions trading system (GX-ETS) portal  (in Japanese)
Renewable Energy Institute「Corporate PPA: Recent Developments in Japan」(2025 edition, March 2025, in Japanese)
MLIT, Study group on ports for the promotion of offshore wind power (in Japanese)
METI Agency for Natural Resources and Energy and MLIT Ports and Harbours Bureau, "Operational Guideline for the Occupancy Auction Regime in the General Sea Area" (revised June 2026, in Japanese)

Prepared by TKI (Singapore) LLP and Tokyo International (TKI) Law Office. For further discussion of any matter raised in this briefing, please contact Earl Rivera-Dolera (earl.dolera@tkilaw.com) and Hojung Jun (hojung.jun@tkilaw.com).

（Written by：Earl Rivera-Dolera,Hojung Jun, Mitsuyuki Okuyama）

*This newsletter is provided for educational and informational purposes only, and is not intended and should not be construed as legal or tax advice. For more information and questions regarding this column, reach out to us.

Earl Rivera-Dolera is an international dispute resolution specialist with extensive experience representing clients and sitting as an arbitrator in high-stakes energy, construction, and cross-border disputes across Asia-Pacific and Europe. She has acted in over 200 international matters with total claims exceeding US$10 billion, including arbitrations under major rules such as ICC, SIAC, JCAA, and HKIAC. Prior to TKI, she served as Partner and Head of International Arbitration at Frasers Law Company (formerly Freehills) in Vietnam.

• Bar Admissions & Qualifications: Solicitor (England & Wales)/ Attorney-at-Law (New York, Texas, Philippines)

• Professional Affiliations: Fellow, Chartered Institute of Arbitrators (FCIArb)/Fellow, Singapore Institute of Arbitrators (FSIArb)

Hojung Jun is our energy and infrastructure partner with multi-jurisdictional experience advising sponsors, developers, and contractors on energy, infrastructure, and mining assets across APAC, the Americas, Europe, the Middle East, and Africa. She regularly advises on transactions such as acquisitions, joint ventures, and divestments as well as project development, construction, and energy transition strategies. She brings deep insights from her private practice roles at international law firms in Tokyo and Singapore, as well as secondments to major Japanese companies and an in-house counsel role with an international construction company.

• Core Focus: Offshore Wind Development, Cross-Border Energy M&A/JVs, Construction, Project Development (renewable energy, power and other infrastructure, LNG facilities).

• Bar Admissions & Qualifications: Registered Foreign Lawyer in Japan (Gaikokuho-Jimu-Bengoshi; Tokyo Bar Association; Primary Jurisdiction: New York)/ Attorney-at-Law (New York State Bar)

• Professional Affiliations:
  Executive Committee Member, Society of Construction Law Japan (SCL Japan)/ Legal & Contract Sub-committee Member, Engineering Advancement Association of Japan (ENAA)/
  Member, Women in Law Japan (WILJ)/Member, International Construction and Energy Law Society of Korea

Mitsuyuki Okuyama is a Japanese-qualified attorney (Bengoshi) with more than 13 years of practice advising Japanese and foreign investors on structured finance, renewable energy, construction, and real estate transactions. Prior to TKI, he practiced at Mori Hamada & Matsumoto. Uniquely dual-credentialed with both legal qualifications and a Second-Class Architect license, Mitsuyuki provides practical, technical-driven counsel across the entire lifecycle of energy, infrastructure, and real assets in Japan.

• Bar Admissions & Professional Credentials: Attorney-at-Law, Japan (Tokyo Bar Association)/ Licensed Second-Class Architect, Japan/ Licensed Real Estate Transaction Agent, Japan