This article introduces a project overview of the Chiba Isumi Wind, which has been designated as a “Promising Zone” under Japan’s Act on Promoting the Utilization of Sea Areas for the Development of Marine Renewable Energy as of October 2025.
The information will be updated as new details become available based on publicly accessible sources.
Other “Promising Zones” can be found in Japan’s Offshore Wind “Promising Zone” Projects — Candidate Areas for Auctions.
1. Project Overview
| Project name | TBD |
| Developer | 7 developers are under EIA process |
| Consortium Members | TBD |
| Location | Offshore Isumi City, (Chiba) |
| Type | Fixed-bottom offshore wind power |
| WTG | TBD |
| Supply price | TBD |
| Capacity | Approx. 400 MW |
| Start of Construction | TBD |
| Operation Period | TBD |
2. Location and Site conditions
2-1. Wind Conditions
The wind speed within the zone is approximately 7.5–8.5 m/s (at 100 m altitude).
2-2. Water Depth
The water depth within the zone is generally 30 m or less.
2-3. Seabed Conditions
TBD
2-4. Port Infrastructure
There are multiple fishing ports in the vicinity of the zone, and the nearby port area is Okitsu Port.
3. Consortium Members
TBD
4. Project Implementation Structure
TBD
5. Project Schedule
5-1. Overall schedule
- February 1, 2022: 1st Statutory Council Meeting
5-2. 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）いすみ市沖洋上風力発電事業 Offshore Wind Power Project off Isumi City | 千葉洋上風力株式会社 Chiba Offshore Wind Power Co., Ltd. | 配慮書 Scoping Document | Up to 500MW | Up to 40 | 12 – 16MW | 2026/01/07 |
| （仮称）いすみ市沖洋上風力発電事業 Offshore Wind Power Project off Isumi | 合同会社いすみ沖洋上風力 Isumi Offshore Wind Power Generation Co., Ltd. | 配慮書 Scoping Document | Up to 564MW | Up to 47 | 12 – 15MW | 2026/01/07 |
| （仮称）千葉県いすみ市沖における洋上風力発電事業 Offshore Wind Power Project off Isumi City | 三菱商事洋上風力株式会社 Mitsubishi Corporation Offshore Wind Ltd. | 配慮書 Scoping Document | Up to 564MW | Up to 40 | 12 – 15MW | 2025/07/07 |
| （仮称）千葉県いすみ市沖洋上風力発電事業 Offshore Wind Power Project off Isumi City | 株式会社レノバ Renova, Inc. | 配慮書 Scoping Document | Up to 450MW | 30 – 47 | 9.5 – 15MW | 2025/06/03 |
| （仮称）いすみ市沖洋上風力発電事業 Offshore Wind Power Project off Isumi City | 三井物産株式会社、RWE Renewables Japan合同会社、大阪ガス株式会社、Ｋ＆Ｏエナジーグループ株式会社 Mitsui & Co., Ltd.; RWE Renewables Japan G.K.; Osaka Gas Co., Ltd.; K&O Energy Group Inc. | 配慮書 Scoping Document | Up to 495MW | 33 – 42 | 12 – 15MW | 2025/06/03 |
| （仮称）千葉県いすみ市沖洋上風力発電事業 Offshore Wind Power Project off Isumi City | 東京電力リニューアブルパワー株式会社 TEPCO Renewable Power, Inc. | 配慮書 Scoping Document | Up to 660MW | 33 – 44 | 15 – 20MW | 2025/06/03 |
| （仮称）いすみ市沖洋上風力発電事業 Offshore Wind Power Project off Isumi City | 株式会社グリーンパワーインベストメント Green Power Investment Corporation | 配慮書 Scoping Document | Up to 630MW | Up to 45 | 14MW | 2022/06/21 |
Source: Environmental Impact Assessment Case Information (Ministry of the Environment, Japan)
Summary
Other “Promising Zones” can be found in Japan’s Offshore Wind “Promising Zone” Projects — Candidate Areas for Auctions.
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