Tokyo Century and MIRARTH Energy Solutions are jointly developing a 12MW/65.8MWh grid-scale battery storage project in Yokohama City, Kanagawa Prefecture, the companies announced on August 29, 2025.
According to the statement, the facility, to be owned by the special purpose company MIRAI Tokyo Chikuden LLC and built on an 8,000m2 site, is expected to be commissioned in FY2029. It is one of the 12 projects subsidized by the Tokyo Metropolitan Government under its FY2024 program for promoting grid-scale BESS deployment. The subsidy will cover approximately 1.7 billion yen of eligible capital expenditures.
The project is MIRARTH’s first-known extra high-voltage grid-scale BESS. In mid-2024, the company said it was developing a 2MW/7.4MWh high-voltage project in Aikawa Town, Kanagawa Prefecture, but did not disclose its planned COD.
Tokyo Century, together with Osaka Gas and Itochu, commissioned its first grid-scale BESS project, an 11MW/23MWh asset in Osaka, earlier this month. The company is also developing a 20MW/79MWh project in Hokkaido jointly with JFE Engineering and its first wholly-owned and unsubsidized project in Nagasaki. It also invested in Tokyo government’s public-private storage-focused fund and acquired 5% of TESS Holdings as part of a broader partnership covering renewables and BESS.
