Bison Energy signed a Heads of Terms agreement with Engelhart CTP for Japan’s first known 10-year grid-scale battery storage asset revenue floor agreement, the company announced on July 7, 2025.
“This agreement marks an important step in bringing long-term revenue certainty to battery storage projects in Japan,” said Ante Pogacic, Head of Renewables, EU Power & Gas at Engelhart. The structure will allow Bison Energy to cap downside risk while maintaining a potential upside in its projects.
The agreement follows a partnership between Bison Brothers, a BESS-focused affiliate of Bison Energy, and the power trading and asset optimization company announced in February 2025.
In a LinkedIn comment on Bison Energy’s announcement, the company’s CEO Michael Zhang said the company is planning to invest in and commission an additional 10 to 15 high-voltage BESS assets by the end of 2026. “As of now, our total BESS development pipeline in Japan has exceeded 2GW,” he added. The company did not disclose specific projects being considered under the new framework.
Separately from the high-voltage projects, Bison Energy also won contracts for three projects in Japan’s second long-term decarbonization auction (LTDA), including 50MW and 40MW projects in Niigata and Fukui, respectively, and a 150MW, six-hour-plus project in Fukushima Prefecture.
Unlike tolling agreements, which are also still in their infancy in Japan, revenue floor structures share risk between asset owners and traders. More such deals are likely as developers seek predictable revenues to ensure project bankability and traders look to hedge risk in a still-evolving market. The upcoming exclusion of sub-six-hour duration assets from the LTDA may further incentivize such partnerships.
