TEPCO Holdings and NTT Anode Energy commissioned the 2MW/9.3MWh Tsumagoi Power Storage Station in Tsumagoi Village, Gunma Prefecture, on May 15, 2025.
According to their statement, the asset is owned by Tsumagoi Chikudensho LLC, a 50:50 joint venture between the two established in November 2023. Its construction was supported through a 187 million yen subsidy received through METI’s FY2022 revised budget program for supporting grid-scale storage. The project is fully-merchant, with planned participation in the wholesale and balancing markets starting FY2025 and the capacity market from FY2027.
Tsumagoi Power Storage Station is TEPCO’s first operational grid-scale battery storage project.
For NTT Anode Energy, it follows the 1.4MW/4.2MWh Tagawa Power Storage Station commissioned jointly with Kyushu Electric Power and Mitsubishi Corporation in July 2023 and the 2MW/8.2MWh Fukuoka Wakamatsu Power Storage Station commissioned in April 2025, both in Fukuoka Prefecture.
“In the future, we aim to further develop our energy storage business by, among other things, validating storage batteries’ use case to help ease grid congestion, in preparation for the large-scale deployment of renewable energy,” said the companies.
