The Oga Katagami Akita Offshore Wind Power Project is a transformative initiative designed to accelerate Japan’s transition toward renewable energy. Located off the coasts of Oga City, Katagami City, and Akita City in Akita Prefecture, this project will contribute to the nation’s clean energy ambitions while fostering economic growth and technological innovation. With a planned capacity of 315 MW, the project underscores Japan’s commitment to offshore wind development.
➡ For an overview of all ten Promotion Areas as of 2025, see:
Promotion Areas for Offshore Wind in Japan – 2025 Overview
1. Project Overview
| Project name | Oga Katagami Akita Offshore Wind |
| Developer | Oga Katagami Akita Offshore Green Energy LLC |
| Partners | JERA Co., Inc. Electric Power Development Co., Ltd. Tohoku Electric Power Co., Inc. ITOCHU Corp. |
| Location | Offshore Oga Katagami Akita City, AKITA Prefecture |
| Type | Fixed-bottom Offshore Wind Power |
| WTG | vestas |
| Price | 3 JPY/kWh |
| Capacity | 315 MW (15 MW × 21 turbines) |
| Start of Construction | march 2026 |
| Operation Period | june 2028 – 2053 |
2. Location and Site conditions
2-1. Wind Conditions
The wind speed within the zone is approximately 6.5–7.5 m/s (at 100 m altitude).
2-2. Water Depth
The water depth within the zone is less than 30 m.
2-3. Port Infrastructure & Grid Connection
Construction port (turbines and foundations): Akita Port.
O&M port: Funakawa Port.
The project is planned to connect to the onshore transmission grid (Akita Substation, etc.) and transmit power within the Tohoku Electric Power service area.
3. Project Overview
A robust framework has been established through a consortium of members with extensive experience in offshore wind power and regional revitalization, supported by partner companies well-versed in domestic and prefectural offshore wind projects.
3-1. Consortium Members
JERA
- Japan’s largest electric power company
- Extensive experience in offshore wind projects in Taiwan and Europe
J-Power (Electric Power Development Co., Ltd.)
- Over 70 years of experience in power generation
- Operates approximately 100 power plants, including domestic port-based offshore wind and onshore wind projects within the prefecture
Tohoku Electric Power Co., Inc.
- The largest electric utility in the Tohoku region
- Operates the region’s leading electricity retail business
ITOCHU Corporation
Top performer nationwide in CPPA (Corporate Power Purchase Agreements)
※ CPPA: Long-term electricity supply contracts
One of Japan’s leading trading companies, guided by the corporate philosophy of “Sanpo Yoshi” (good for the seller, the buyer, and society)
3-2. Construction and Operation & Maintenance Framework
| Scope | Company |
|---|---|
| Wind Turbine Supply & Installation | Vestas |
| Foundation Procurement & Installation (SEP Vessel) | Kajima Corporation |
| Onshore Construction | Multiple Electrical Contractors |
| Wind Turbine SEP Vessel | Goyo Construction |
| Cable Supply & Installation | Sumitomo Electric |
| Scope | Company |
|---|---|
| Wind Turbine Inspection & Repair | Vestas / O&M Subsidiary |
| Balance of Plant (BOP) | J-Power Hi-Tech and others |
| CTV Supply & Marine Operations | Japan Post Shipping JV |
4. Project Timeline & Development Phases
4-1. Overall schedule
- January 25, 2022: 1st Statutory Council Meeting
- May 10, 2022: 2nd Statutory Council Meeting
- June 24, 2022: 3rd Statutory Council Meeting
- August 2, 2022: 4th Statutory Council Meeting
- October 29, 2024: 5th Statutory Council Meeting
- February 25, 2026: 6th Statutory Council Meeting
| Phase | Timeline |
|---|---|
| Environmental Impact Assessment | CY23–CY25 |
| Seabed Survey | CY23–CY24 |
| Wind Condition Survey | CY23–CY24 |
| Detailed Design | CY23–CY25 |
| Conformity Assessment / WF Certification | CY24–CY26 |
| Port Base Utilization | From Jan CY25 onward |
| Onshore Substation Work | From CY25 |
| Foundation Installation | From Apr CY27 |
| Subsea Cable Installation | From May CY27 |
| Wind Turbine Installation | From Aug CY27 |
| Commissioning (Trial Operation) | CY27–CY28 |
4-2. EIA status
| 事業名称 Project name | 事業者名 Developer | 手続段階 EIA Stage | 容量 Capacity | 基数 Turbines | 出力 Rating | 更新日 Last Updated |
|---|---|---|---|---|---|---|
| （仮称）男鹿市、潟上市及び秋田市沖洋上風力発電事業 Oga Katagami Akita Offshore Wind | 男鹿・潟上・秋田Offshore Green Energy合同会社 Oga Katagami Akita Offshore Green Energy LLC | 準備書 EIA Draft report | 315MW | 21 | 15MW | 2025/09/24 |
Source: Environmental Impact Assessment Case Information (Ministry of the Environment, Japan)
5. LCOE and IRR Estimation
Evaluating the bankability of offshore wind projects requires close attention to key cost indicators such as LCOE (Levelized Cost of Energy) and IRR (Internal Rate of Return). However, in Japan’s Promotion Zones, detailed project-level cost information remains limited in publicly available materials. As a result, investors and developers often lack sufficient data to form a fully informed assessment.
To address this gap, DeepWind applies a proprietary cost model using representative site conditions for each project, including wind resource (capacity factor), water depth, distance to port, and distance to grid connection point. Based on these input parameters, we estimate CAPEX, OPEX, LCOE, and IRR in a consistent framework.
This approach allows us to provide a cross-project comparison of the relative economic positioning of Japan’s Promotion Zone projects.
▶ For the latest model assumptions and updated relative positioning, please refer to the cost analysis Pillar article below.
👉 Cost Realities of Japan’s Offshore Wind: Analyzing LCOE and IRR Across 12 Promotion Zones (Latest Edition)
Conclusion
The Oga Katagami Akita Offshore Wind Power Project is a crucial milestone in Japan’s offshore wind expansion. With its emphasis on sustainability, economic revitalization, and cutting-edge technology, the project positions Japan as a leader in the global renewable energy market.
To explore how this area compares nationally and understand Japan’s offshore wind roadmap, visit:
Promotion Areas for Offshore Wind in Japan – 2025 Overview —
your guide to Japan’s offshore wind Promotion Areas.
Explore more categories at DeepWind:
- 🔍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.