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
2-1. Sea & Geographical Features
The waters off the coast of the Oga Peninsula in central Akita Prefecture. The area is on a relatively shallow continental shelf, and the ocean conditions are stable except during major typhoons. The water depth is about 30m.
2-2. Port Infrastructure & Grid Connection
The base port will be Akita Port (designated port in Akita Prefecture). It will be connected to the land power grid (Akita substation, etc.) and transmit electricity to the Tohoku Electric Power Company 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 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 / Furukawa Electric |
3-3. Operation & Maintenance Framework
| 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 / Tokyo Kisen JV |
4. Project Timeline & Development Phases
| Phase | Timeline | Notes |
|---|---|---|
| Environmental Impact Assessment | CY23–CY25 | Early completion of EIA, wind, seabed, and detailed design phases |
| 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 |
4-1. Start of Commercial Operation: CY28
- Construction will incorporate experience from Europe and Taiwan
- Environmental impact assessment, wind & seabed surveys, and detailed design are already progressing ahead of schedule
5. CAPEX & OPEX Estimates (Based on NEDO Model)
The capital expenditure (CAPEX) and operational expenditure (OPEX) estimates follow the latest NEDO offshore wind cost model.
The estimated capital expenditure (CAPEX) for the Chiba Choshi Offshore Wind is approx. ¥130 billion ($0.9 billion USD), with long-term operational costs (OPEX) projected at approx. ¥2.2 billion annually.
📌 CAPEX & OPEX Breakdown for 315 MW:
| Investment Factor | Estimated Cost (Billion JPY) |
|---|---|
| Turbine Procurement | 71 |
| Foundation & Installation | 49 |
| Substations & Grid Connection | 9 |
| Operations & Maintenance (OPEX/year) | 2.2 |
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.
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- 🌊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.
