Idemitsu Kosan’s wholly-owned subsidiary Solar Frontier and GLP’s wholly-owned subsidiary FPS partnered to help solar power plant owners with feed-in-tariff (FIT) to feed-in-premium (FIP) conversions and battery storage retrofits, the companies announced on August 27, 2025.
According to the statement, the partners are currently working on multiple such projects.
Solar Frontier handles feasibility studies and proposal preparation and helps customers explain the scheme to finance providers. It also supports the administrative procedures required to switch assets to FIP and install storage. Its group company Solar Frontier Engineering handles engineering, procurement, and construction (EPC).
FPS is in charge of preparing financial simulations based on historical data. As an aggregator, it is also be responsible for selling generated power and non-fossil certificates based on generation forecasts and battery operation plans provided by Solar Frontier for converted and retrofitted assets.
The Idemitsu unit develops and sells solar systems and provides EPC and other services, such as generation forecasting. GLP’s FPS, launched in 2021, is a power retailer and aggregator that has, among other projects, been selected by Kaihan to aggregate output from 330 low-voltage solar power plants.
They join a growing list of companies supporting asset owners with FIT-to-FIP conversions and battery co-location amid declining returns from FIT assets due to curtailment, particularly in Kyushu. Other entrants include U-POWER, a joint venture between Omron and Tokyo Century, and PowerX.
