Ukujima Mirai Energy postponed the completion of the 400MWAC/479.28MWDC Ukujima project in Sasebo City, Nagasaki Prefecture, to FY2029, and began exploring a business model not dependent on the feed-in-tariff (FIT) scheme, one of the project’s sponsors, Kraftia, said in its 2026 annual report.
According to the report, the developer is considering switching the planned asset to the feed-in-premium (FIP) scheme, adding battery storage, and selling the output under long-term PPAs to improve its economics. METI data shows the project was FIT-certified in FY2012, when solar power plants were offered 40 yen per kWh for 20 years. Under the new timeline, however, it would only be eligible to receive support for about half of the term.
The power plant, which is located on a remote island that will be connected to mainland Nagasaki via an approximately 64km submarine cable, is currently under construction. Ukujima Mirai Energy’s website shows that works on the third of its six sections began in August 2026. Once complete, the facility is expected to generate about 515GWh annually.
Originally, the total investment was expected to reach about 200 billion yen. Kraftia, which also serves as the engineering, procurement, and construction (EPC) contractor, said that it would disclose the revised amount once determined, as the developer is also considering utilizing battery storage subsidies.
The project was initially developed by Photovolt Development Partners affiliate TeraSol. In 2020, it was transferred to Ukujima Mirai Energy, which was established by six sponsors including Kyocera, SPCG, Kraftia, Tokyo Century, Furukawa Electric, and Tsuboi Industrial.
Completion of the project, which is expected to become Japan’s largest solar power plant by capacity, was first scheduled for June 2023. Prior to the latest postponement, it was delayed to March 2027 due to COVID-19.
