SPARX Group, Kansai Electric Power, and JA Mitsui Lease partnered to build two extra high-voltage grid-scale battery storage facilities in Shizuoka and Ibaraki prefectures, bringing the total to four joint projects totaling 180MW/636.8MWh expected to come online by June 2029.
According to a September 25, 2025, statement, the companies plan to develop a 30MW/110.3MWh asset on a 5,000m2 site in Hamamatsu City, Shizuoka Prefecture, in the Chubu TSO area and a 50MW/175.5MWh project on an 8,000 m2 plot in Mito City, Ibaraki Prefecture, in the Tokyo TSO area. They plan to commission the facilities in June 2028 and June 2029, respectively. Neither of the projects will participate in the long-term decarbonization auction or use other subsidies.
As with their two previously announced 50MW/175.5MWh projects in Sapporo City, Hokkaido, SPARX Group’s subsidiary SPARX Green Energy & Technology will support development, fundraising, and operation. Kansai EPCO will provide battery monitoring and maintenance service and, through its subsidiary E-Flow, participate with the assets in the wholesale, balancing, and capacity markets as their aggregator.
The projects are owned by SGET Hamamatsu Chikudensho LLC and SGET Mito Chikudensho LLC, both special purpose companies (SPCs) with undisclosed economic interest held by SPARX Group and its two partners.
METI data shows that SPARX Group, a TSE Prime-listed investment company, holds stakes in over 400MW of operational FIT/FIP solar, onshore wind, biomass, and geothermal assets. The tie-ups with Kansai EPCO and JA Mitsui Lease are its only known grid-scale storage projects.
Kansai EPCO operates the 48MW/113MWh Kinokawa Power Storage Station jointly with Orix and is also developing a 99MW/396MWh facility with Kinden and Japan Extensive Infrastructure in addition to the SPARX Group-led projects. It targets developing 1GW of grid-scale BESS by the early 2030s.
JA Mitsui Lease has also been active in battery storage outside its partnership with SPARX Group and Kansai EPCO. In May 2024, it partnered with PowerX to develop 30 assets over the next three years. Later that year, it acquired the first three high-voltage projects to be completed under the partnership from Sun Village.
