Project Big Stone Thermal Energy Storage

under construction

US thermal batteries company Antora Energy is commissioning a 5-GWh multi-day thermal energy storage system at biofuel producer Poet’s bioprocessing facility in Big Stone City, South Dakota, under a long-term energy off-take agreement. The system delivers 50 MW of round-the-clock power, helping reduce emissions and lower prices. The project includes over 200 thermal batteries storing electricity as heat in solid carbon blocks. Full completion is expected later in 2026. Grok Ventures is the equity investor, and Otter Tail Power supplies grid power under an approved rate structure. Poet has zero upfront capital expenditure, and the project has created over 300 jobs in California and South Dakota.