CEF H2 submitted the environmental impact assessment methodology for the approximately 149.9MW Ariake H2 Power Plant in Omuta City, Fukuoka Prefecture, which is one of two hydrogen mono-firing projects that have been awarded in Japan’s long-term decarbonization auctions to date.
According to the document made available for public viewing on August 20, 2026, the power plant will replace Miike Power Station’s coal-fired 175MW Unit 2. The company plans to pair the new unit with a 500MW electrolyzer system, hydrogen tanks with a combined capacity of 75t, and lithium-ion batteries totaling 1.3GWh.
Demolition of the existing unit is scheduled to run from June 2027 through February 2028. CEF H2 aims to begin construction of the replacement in August 2028 and commence commercial operations in March 2031.
The methodology is the first environmental impact assessment-related document CEF H2 has submitted. With a capacity between 112.5MW and 150MW, it is categorized as a Class 2 thermal power plant, making it exempt from filing a primary consideration that marks the beginning of the process for larger projects.
OCCTO data shows the project was awarded 146.4MW (derated) in the FY2025 long-term decarbonization auction alongside Hoku Energy’s Daiichi Power Station, which secured 106.65MW.
Miike Power Station’s Unit 1 operated between 1971 and 1988, first for self-consumption by Mitsui Aluminum Industry. Unit 2 was commissioned in 1975.
