SPARX Group, Kansai Electric Power Company (Kansai EPCO) and JA Mitsui Lease are developing two new large-scale battery energy storage systems in the Shizuoka and Ibaraki regions. The two projects total 80MW of capacity and are scheduled to enter service by June 2029, without public subsidies or participation in long-term decarbonisation auctions.
The first site, with a capacity of 30MW for 110.3MWh, will be built on a 5,000 square metre plot in Hamamatsu, within the Chubu transmission system operator (TSO) area. The second, larger site will target 50MW for 175.5MWh and will be located in Mito, Ibaraki Prefecture, within the Tokyo TSO zone. Commissioning is scheduled for June 2028 and June 2029, respectively.
Industry players already active in the market
These projects add to the two other 50MW/175.5MWh facilities the partners are currently developing in Sapporo, Hokkaido. SPARX Green Energy & Technology, a subsidiary of SPARX Group, is responsible for the development, fundraising and operation of the entire portfolio. Kansai EPCO will handle battery monitoring and maintenance, while its subsidiary E-Flow will participate in the wholesale, balancing and capacity markets as aggregator.
The new facilities will be owned by SGET Hamamatsu Chikudensho LLC and SGET Mito Chikudensho LLC, both special purpose companies (SPCs), with no disclosure of the specific financial interests held by the three partners.
Long-term ambitions in grid-scale storage
SPARX Group, listed on the Tokyo Stock Exchange Prime market, already holds interests in over 400MW of solar, onshore wind, biomass and geothermal assets under the FIT (feed-in tariff) and FIP (feed-in premium) schemes. However, its projects with Kansai EPCO and JA Mitsui Lease remain its only investments in grid-scale battery storage to date.
Kansai EPCO, for its part, co-owns a 48MW/113MWh storage station with Orix and is currently developing a 99MW/396MWh facility with Kinden and Japan Extensive Infrastructure. The company targets 1GW of grid-scale battery energy storage systems by the early 2030s.
JA Mitsui Lease is also pursuing an active strategy outside this partnership. In May 2024, the company partnered with PowerX to deploy 30 assets over three years. It later acquired the first three high-voltage projects under the agreement from Sun Village.
