Environmental Impact Assessment of Offshore Wind Farms: Toward the Effective Operation of the New System

Abstract

This article examines the historical development and emerging challenges of Japan’s Environmental Impact Assessment (EIA) system, with a particular focus on the rapid expansion of offshore wind power. Historically, Japan’s EIA practices were shaped by administrative guidance, which resulted in standardized procedures and limited flexibility. Although the 1997 EIA Act shifted responsibility to project proponents, issues such as appropriate scoping and insufficient post-assessment monitoring have become increasingly evident, especially following the inclusion of wind and solar power projects under the Act.

The coexistence of the Marine Renewable Energy Act and the EIA Act has created procedural overlap and confusion in the field of offshore wind development. In response, the 2024 recommendation of the Central Environment Council prompted institutional reforms. The 2025 amendment introduced a new division of roles in which the national government conducts preliminary marine environmental surveys and provides guidance for project-level scoping. To address uncertainties inherent in predicting offshore environmental impacts, the revised framework also establishes centralized management of monitoring data and systematic accumulation of scientific knowledge.

This paper positions these reforms as a critical turning point for reconciling the expansion of offshore wind power with appropriate environmental safeguards. It highlights the perspectives necessary for the effective implementation of Japan’s new EIA framework and its contribution to both environmental protection and the sustainable deployment of offshore wind energy.