SNG Holdings confirmed it began trial operations on October 15 at the Gotemba High-Voltage Power Storage Station, a 2MW/6MWh facility. The site, located in Gotemba in Shizuoka Prefecture, sits on the transmission network of Tokyo’s grid operator. The system uses cabinet-type lithium batteries supplied by Gotion High-tech Co., Ltd.
The project is developed by Gotemba Koatsu Chikudensho LLC, a special purpose company owned 87.10% by SNG Holdings, a group based in Akita linked to construction firm Sangi. Digital Grid Asset Management holds 10.75%, while PHOTON CAPITAL and PHOTON JAPAN jointly own the remaining 2.15%. The facility will be aggregated by Digital Grid for grid optimisation purposes.
A new segment for SNG Holdings
The Gotemba initiative marks SNG Holdings’ entry into large-scale energy storage. The company stated it intends to use this project as a reference to deploy over 300MW of storage systems across the Tohoku grid operator’s territory. Prior to this diversification, the group built more than 200MW of solar power plants across Japan.
The Gotemba facility was built on a 710 m² plot. The battery system enables 6MWh of storage capacity, with a two-hour discharge duration. This format is aimed at addressing Japan’s growing need for grid flexibility as more intermittent renewable energy sources are integrated.
Digital Grid expands post-IPO
Digital Grid Asset Management, the asset development and management arm of Digital Grid, is using proceeds from its April 2025 initial public offering to invest in storage. The company also develops matchmaking platforms for power purchase agreements (PPAs) and aggregation of solar and wind assets.
The Gotemba project also marks PHOTON CAPITAL’s first investment in grid-scale battery storage. Its participation reflects a shift in investment strategy toward storage assets in addition to conventional renewable infrastructure. The company has not indicated whether additional similar projects are under consideration.
