Release of the 2025 Report on the Environmental Impacts of Large-Scale Onshore Wind Power:
Rethinking the Path Forward for Renewable Energy

The Nature Conservation Society of Japan (NACS-J) (Chairperson: TSUCHIYA Toshiyuki) released the 2025 Report on the Environmental Impacts of Large-Scale Onshore Wind Power Projects on 6 November 2025.

The full report is available at the link below (only in Japanese).

Climate change is seriously impacting ecosystems worldwide. According to the Red List of the International Union for Conservation of Nature (IUCN), as of 2025, 7,695 threatened species are affected by climate change. In response to this situation, there is a global call for urgent action to reduce greenhouse gas emissions, and the Japanese government has pledged to achieve carbon neutrality by 2050 and is promoting a transition from fossil fuels to renewable energy.

At the same time, however, the development of renewable energy has seen emerging negative impacts on the natural and residential environment, with increasing conflicts associated with construction of power plants in various regions. While accelerating the transition to renewable energy is essential for the environment, projects that cause irreversible damage to ecosystems or local living environments are not desireable and may undermine public trust in renewable energy.

This report focuses specifically on the impacts of large-scale onshore wind power projects on the natural environment. In addition to updates on latest developments, the report newly includes projects that were not covered in previous editions and evaluates the environmental impacts of nearly all large-scale onshore wind power projects in Japan, including those in the planning stage. It also analyses findings from field surveys described in Environmental Impact Assessment (EIA) documents, as well as opinions issued by the Minister of the Environment, in order to clarify the actual status of environmental considerations taken by each project developer.

Key Points of the Report

• As of September 2025, the report independently analyzed 512 onshore wind power projects that are either operational or under development. Based on EIA documents and related materials, it evaluates nearly all large-scale onshore wind power projects in Japan. The analysis newly includes projects that issued EIA documents prior to 2017 and projects that have not undergone environmental assessment, which had not been covered in previous evaluations.
• A comparison of large-scale onshore wind projects (over 40,000 kW) and solar power projects shows that while many solar facilities are already in operation, numerous onshore wind projects remain in the planning stage across the country. This raises concerns that negative impacts on the natural environment may become more apparent in the future. Unlike solar power facilities, onshore wind power projects can cause bird collisions—particularly involving birds of prey—not only during construction but also throughout operation. As long as they remain operational, their impacts on the natural environment may be ongoing and potentially more severe than those of solar power generation.
• The analysis clearly reveals significant differences among project developers in their level of consideration for the natural environment. Approximately 10% of the projects reviewed (including those in planning) may pose particularly serious risks to ecosystems.
• As appropriate site selection is critical to responsible development of onshore wind power, public disclosure of EIA documents and the sharing of environmental data are essential to enable prompt assessment of cumulative environmental impacts. The revised Environmental Impact Assessment Act (June 2025) is expected to promote continuous public access to EIA documents by project developers.
• Companies are increasingly shifting their power sources to renewable energy and investing in renewables as part of their climate strategies. However, such efforts must involve comprehensive, multi-faceted examination of potential impacts on biodiversity to ensure that renewable energy initiatives are genuinely sustainable.