Hokkaido Hiyama Offshore Wind Project

The Hokkaido Hiyama Offshore Wind Power Project has been designated as a candidate area under Japan’s 4th round of promotion area tenders (commonly referred to as “Round 4”) based on the Act on Promoting Utilization of Sea Areas for Renewable Energy. It is positioned as a key project contributing to the national goal of securing 10 GW of offshore wind capacity by 2030 and 30–45 GW by 2040.

With a planned total generation capacity of up to 1,140 MW, this project is expected to be one of the largest offshore wind developments in Japan. It will significantly contribute to the country’s decarbonized power mix while also promoting regional industrial growth and economic revitalization.

As of July 30, 2025, the project area has been officially designated as a promotion zone. While public information on the project remains limited at the time of writing, we will continue to provide timely updates on developer selection, project schedules, and more—so stay tuned!

➡ 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	TBD (To be determined)
Developer	TBD (Currently under consideration by Hokkaido Electric Power, J-POWER, TEPCO RP, Cosmo Eco Power, HOWD/CIP, and others)
Consortium Members	TBD
Location	Hokkaido Hiyama Offshore
Type	Fixed-bottom Offshore Wind Power (Estimated)
WTG	TBD
Price	TBD
Capacity	Approximately 910–1,140 MW (estimated: 76 turbines × 15 MW)
Start of Construction	TBD (Estimated: from 2027 to the early 2030s)
Operation Period	TBD

2. Location and Site conditions

2-1. Wind Conditions

The wind speed within the zone is approximately 7.0–9.0 m/s (at 100 m altitude).

2-2. Water Depth

Within the zone, approximately 40% of the area has a water depth of 40 m or less, approximately 50% is 50 m or less, and approximately 60% is 60 m or less.
The deepest point within the zone reaches approximately 245 m.

2-3. Seabed Conditions

Based on the results of SSS and acoustic surveys, exposed bedrock has been confirmed in coastal areas.
According to the SSS data, the area ratio of sandy mud zones to exposed rock zones is approximately 4:1.

2-4. Port Infrastructure

Esashi Port is expected to serve as the primary base for construction and operations.

3. Consortium Members

TBD

4. Project Implementation Structure

TBD

5. Project Schedule

5-1. Overall schedule

• December 18, 2023: 1st Statutory Council Meeting
• July 22, 2024: 2nd Statutory Council Meeting
• November 8, 2024: 3rd Statutory Council Meeting
• March 19, 2025: 4th 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）北海道檜山沖洋上風力発電事業 Hokkaido Hiyama Offshore Wind Power Project	北海道洋上風力開発合同会社 Hokkaido Offshore Wind Development GK	配慮書 Scoping Document	Up to 1500MW	Up to 135	10 – 24MW	2026/1/27
（仮称）檜山沖における洋上風力発電事業 Offshore Wind Power Project off Hiyama	北海道電力株式会社 Hokkaido Electric Power	配慮書 Scoping Document	Up to 360MW	15 – 25	14 – 22.6MW	2025/12/25
（仮称）北海道檜山地方洋上風力発電事業 Hokkaido Hiyama Offshore Wind Power Project	関西電力株式会社、RWE Renewables Japan合同会社 Kansai Electric Power, RWE Renewables Japan GK	配慮書 Scoping Document	Up to 1680MW	Up to 120	14 – 24MW	2025/4/28
（仮称）檜山沖洋上風力発電事業 Offshore Wind Power Project off Hiyama	コスモエコパワー株式会社 Cosmo Eco Power	配慮書 Scoping Document	Up to 1000MW	Up to 100	10 – 20MW	2023/9/5
（仮称）檜山エリア洋上風力発電事業 Hiyama Area Offshore Wind Power Project	電源開発株式会社 J-POWER	配慮書 Scoping Document	Up to 722MW	–	–	2019/11/15

6. 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)

Summary

The Hiyama Offshore Wind Project in Hokkaido is a large-scale initiative expected to become a central pillar of renewable energy development in the southern Hokkaido region. With a maximum capacity of 1,140 MW—one of the largest in Japan—it is anticipated to contribute significantly to regional economic revitalization and the realization of a decarbonized society.

As the project moves forward with developer selection, environmental assessments, and grid connection planning, ensuring regional harmony and long-term sustainability will be key themes. We will continue to provide timely updates as the project progresses.

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.