Arup supports certification for Oga, Katagami and Akita Offshore Wind Project

On 30 June 2026, the project developer obtained certification from Bureau Veritas Japan Co., Ltd., a registered conformity assessment body in Japan. The certification confirms that the design of the offshore wind power facilities complies with Japanese technical standards and regulatory requirements, representing a key milestone toward construction plan approval under the Electricity Business Act.

The project involves key stakeholders including Kajima Corporation (partnering with Kobori Research Complex Inc./COWI A/S), responsible for monopile foundation design, and Vestas Japan Co., Ltd. and MHI Vestas Japan Co., Ltd., responsible for wind turbine and tower design. The certification was achieved through close collaboration among all parties, encompassing site condition assessment, development of design criteria, global load analysis and design verification of both support structures and wind turbines.

The project marks several significant firsts. It is the first bottom-fixed offshore wind project in Japan’s general sea areas to obtain conformity certification through the public auction process, and the first certified offshore wind project in the country featuring turbines exceeding 10MW in capacity. The project also incorporates design considerations specific to Japan’s natural conditions, including seismic factors — notably representing the world’s first design case for a 15MW-class offshore wind turbine to explicitly account for earthquake effects.