DeepWind News Digest delivers key updates on Japan’s offshore wind sector in English every week.
This article provides a full digest of the major developments in December 2025.
December 1st Week
1. Seven Structural Reforms that Will Shape Round 2 and Round 3
In November 2025, Japan’s Ministry of Economy, Trade and Industry (METI) and the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) released a major policy package titled “Measures to Ensure the Successful Completion of Offshore Wind Projects.” The document was developed in direct response to the withdrawals seen in Japan’s first offshore wind tender round. It sets out a comprehensive suite of reforms aimed at securing the successful delivery of upcoming Round 2 and Round 3 projects.
This article summarizes the key points of the government’s policy update and, more importantly, provides DeepWind’s view on what these seven measures mean for Japan’s offshore wind market from a practical, financial, and strategic perspective.
2. What Is Japan’s LTDA? A Clear Guide to the Long-Term Decarbonization Auction and Its Impact on Offshore Wind
Japan is placing increasing emphasis on the Long-Term Decarbonization Power Supply Auction (LTDA) as a central component of its energy policy. Developing decarbonized power sources requires massive capital investment—often hundreds of billions of yen—yet power market prices in Japan remain highly volatile. Under such conditions, traditional FIT and FIP schemes no longer provide sufficient revenue certainty for large-scale, capital-intensive renewable projects.
To address this challenge, the government introduced the LTDA as a new mechanism designed to guarantee recovery of fixed costs (CAPEX + fixed OPEX) over a 20-year period.
This article provides a comprehensive and up-to-date explanation based on the latest public documents.
3. What Is Scope 2? Definition, Examples, Calculation Methods, and the Market-Based vs Location-Based Approaches
Corporate greenhouse gas emissions are classified into Scope 1, Scope 2, and Scope 3 depending on where the emissions originate. Among these categories, Scope 2—indirect emissions from purchased electricity—is the area where companies can most quickly reduce their emissions and is the core of any renewable electricity procurement strategy.
In particular, Corporate PPAs (Power Purchase Agreements), which are increasingly adopted by companies in Japan, are a central tool for reducing Scope 2 emissions.
This article summarizes the essential concepts behind Scope 2—its definition, calculation methods, and the difference between the location-based and market-based approaches. These concepts form a necessary foundation for understanding how Corporate PPAs work.
December 2nd Week
1. Battery-powered “electric cargo vessels” begin trials in Yakushima – a potential alternative to subsea cables and support for offshore wind
Kaijo Power Grid, a subsidiary of PowerX, has launched demonstration tests of battery-powered “electric cargo vessels” in Yakushima. The project aims to store hydropower generated on the island and transport it to nearby remote islands such as Tanegashima, with commercial operation targeted around 2028. In addition to supporting decarbonisation in island regions, the concept is also being viewed as a future alternative to subsea cables in areas where installation is difficult, with potential applications for floating offshore wind and cost reduction in power transmission.
Source: The Sankei Shimbun
2. Japan’s first commercial floating offshore wind project to start operation off Goto, Nagasaki
A floating offshore wind farm off Goto City in Nagasaki Prefecture is set to begin commercial operation in January 2026, becoming Japan’s first operational floating project. Local business groups have formed a study association to develop related industries, including component manufacturing, in preparation for the project. Over 40 billion yen in economic ripple effects are expected over the 20-year maintenance period, and the site is also anticipated to attract tourism.
Source: Nikkei (Japanese)
3. Japan achieves first offshore LPS inspection using the “Dr.Bee” drone — a major step toward next-generation wind turbine maintenance
Fukushima Sangikyo has announced Japan’s first successful offshore LPS (Lightning Protection System) inspection of a wind turbine blade using its proprietary drone system “Dr.Bee.” After commercializing the service for onshore turbines in March 2025 and completing inspections for 130 units within nine months, the company has now demonstrated that the same technology can be applied offshore. The drone-based method addresses longstanding challenges of rope-access inspections, including safety risks, a shortage of skilled technicians, and rising maintenance costs. This milestone marks a significant step toward practical offshore deployment, and the company plans to further develop and expand its maintenance services for the offshore wind sector.
Press release: Sangikyo
December 3rd Week
1. Akita Offshore Wind Project Moves Forward with Final Guarantee Payment
A consortium led by JERA, together with J-Power, Tohoku Electric Power, and Itochu, has completed the final guarantee payment required to continue its offshore wind project off the coast of Akita Prefecture. The guarantee is paid in three stages under Japan’s offshore wind auction framework, and this marks the third and final payment.
The total guarantee amount is estimated at around JPY 4 billion, with part of the amount subject to deductions. Under the government’s auction rules, guarantee payments are forfeited in full if a project is withdrawn, making this step a clear signal of the consortium’s commitment to proceed.
The project plans to install 21 fixed-bottom turbines with a total capacity of 315 MW, targeting commercial operation in June 2028.
Source: Nikkei (Japanese)
2. Offshore Wind Projects off Niigata and Nagasaki Show Progress Toward Continued Development
In Niigata Prefecture, a consortium of Mitsui & Co., Osaka Gas, and RWE Japan has paid the final installment for the Murakami–Tainai offshore wind project. Total guarantees are estimated at around JPY 9 billion, with commercial operation targeted for June 2029.
In Nagasaki Prefecture, a consortium led by Sumitomo Corporation and TEPCO Renewable Power has also completed guarantee payments for the Enoshima offshore wind project, with total guarantees estimated at around JPY 5 billion and operations expected to begin in August 2029.
While these payments confirm intent to proceed, cost pressures and turbine supply challenges remain.
Source: Nikkei (Japanese)
3. What Has Changed in Japan’s Offshore Wind Policy? An Integrated Review of Auction Reform and Project Support Measures (2025)
Between November and December 2025, a series of policy updates were announced concerning Japan’s offshore wind sector, covering both reforms to the auction system and new measures to improve the project execution environment.
At first glance, these may appear to be a collection of separate institutional adjustments. However, when read together, they reveal a clearer shift in policy priorities and underlying concerns on the government side.
This article does not treat auction reform—how developers are selected—and project environment measures—how selected projects are supported—as separate topics. Instead, it examines them as a single, integrated policy package, and explores what these changes mean for Japan’s offshore wind market.
December 4th Week
1. U.S. Temporarily Halts Offshore Wind Construction Over National Security Concerns
The U.S. Department of the Interior announced a temporary suspension of large-scale offshore wind projects currently under construction in the United States, citing national security concerns. The measure applies to multiple projects under development off the U.S. East Coast.
During the suspension period, the Department of the Interior and the Department of Defense will jointly conduct a risk assessment. This marks the first time that offshore wind projects across the country have been subject to a comprehensive halt, underscoring the growing impact of the current administration’s cautious stance toward renewable energy on the offshore wind sector.
Source: Nikkei
2. METI Analysis Points to Aggressive Bidding as a Factor in Mitsubishi Corporation’s Offshore Wind Withdrawal
METI and MLIT released an analysis on the withdrawal of an offshore wind project planned by a Mitsubishi Corporation–led consortium.
While the report acknowledges the impact of rising material costs and yen depreciation, it also states that “the low bid price cannot be ruled out as a contributing factor” in undermining project profitability. The findings highlight how intensified price competition may have increased business risks, offering important implications for future auction design and pricing mechanisms.
Source: Nikkei
3. Shimizu Corporation to Issue Blue Bonds for Offshore Wind Installation Vessel
清水建設 announced plans to issue JPY 10 billion in blue bonds in January 2026 to refinance the construction cost of its self-elevating platform (SEP) vessel, BLUE WIND, used for offshore wind installation.
This will be Japan’s first blue bond issuance dedicated to an SEP vessel. The bond framework has been assessed as compliant with ICMA’s Green Bond Principles and Japan’s environmental guidelines.
Source: Shimizu Corporation IR
Monthly Wrap-up
December 2025 marked a turning point for Japan’s offshore wind sector, as policy adjustments and project selection progressed in parallel. While institutional reviews and support schemes evolved in response to Round 1 withdrawals, several projects in Akita, Niigata, and Nagasaki demonstrated continued commitment through guarantee payments. At the same time, advances in floating wind commercialization, supporting technologies, and offshore infrastructure financing suggest that the sector is moving from an expansion phase toward one where long-term viability and execution capability are increasingly under scrutiny.
📘 Explore the full-year summary
Catch up on all key offshore wind developments throughout 2025 —
including project updates, policy trends, and floating wind milestones.
👉 Read the Japan Offshore Wind News Digest 2025 (Year in Review)
➡ Japan Offshore Wind News Digest – 2025
Weekly digest with actionable insights for investors, developers, and stakeholders in Japan’s offshore wind. 🎁 Welcome gift: Japan Offshore Wind – 2025 Recap & 2026 Outlook (PDF)📩 DeepWind Weekly
- 🔍Market Insights – Understand the latest trends and key topics in Japan’s offshore wind market
- 🏛️Policy & Regulations – Explore Japan’s legal frameworks, auction systems, and designated promotion zones.
- 🌊Projects – Get an overview of offshore wind projects across Japan’s coastal regions.
- 🛠️Technology & Innovation – Discover the latest technologies and innovations shaping Japan’s offshore wind sector.
- 💡Cost Analysis – Dive into Japan-specific LCOE insights and offshore wind cost structures.
