Green Growth secured its first feed-in-tariff (FIT) to feed-in-premium (FIP) conversion and storage co-location support deal with Fukuoka-based Kagashiya, the company announced on July 23, 2025.
According to the statement, Green Growth will support the conversion of Kagashiya’s 1.5MWAC/1.8MWDC solar power plant in Hita City, Oita Prefecture, and oversee the addition of a 1.5MW/4.5MWh battery storage system to the asset. Construction work began in June 2025, with commissioning expected in January 2026.
Once the BESS is operational, Green Growth will aggregate the asset using Shizen Connect, marking the first third-party use of the energy management system developed by a wholly-owned subsidiary of Shizen Energy.
The power plant was FIT-certified in FY2013 and operates under a 36 yen per kWh contract valid until September 2037. After conversion, it will maintain the current FIT price as the strike price used for calculating the market-based FIP premiums.
Green Growth aims to scale its FIT-to-FIP conversion service in the Kyushu area, which has been affected by curtailment most significantly, before expanding to other regions.
According to METI data, Kagashiya owns 21 other operational solar projects in Kyushu, including a 248kWAC/338kWDC power plant in Saga Prefecture, a 1MWAC/1.2MWDC asset in Fukuoka Prefecture, and 19 low-voltage, sub-50kWAC systems also in Fukuoka. With solar being only a minor part of its business, Kagashiya lacks the capabilities to operate FIP assets, instead relying on Green Growth.
Other asset owners such as SMFL Mirai Partners and Tokyo Century have also begun converting some of their FIT projects in Kyushu to FIP and adding storage to offset revenue losses from curtailment.
