Poet Biofuels, Antora Energy launch new energy storage in South Dakota

POET Biofuels and Antora Energy have inaugurated a 5 gigawatt-hour thermal energy storage system in Big Stone City, South Dakota, adjacent to POET’s ethanol plant. The facility captures excess wind energy that would otherwise be lost due to grid capacity limits, storing it in carbon blocks heated to 4,000 degrees Fahrenheit for later use. The project marks Antora’s first commercial-scale deployment of its thermal storage technology, which converts low-cost off-peak energy into heat stored in insulated carbon blocks. When needed, the heat is transferred into oil for power generation, ensuring a steady energy supply for POET’s ethanol production. POET Biofuels, the world’s largest ethanol producer, will benefit from a more reliable energy source, reducing costs for ethanol at gas pumps. South Dakota corn growers will also gain expanded markets for their grain, as the facility increases ethanol production capacity. Construction has already supported 300 jobs across South Dakota and California, with additional full-time positions expected in Big Stone City. The project received private financing, including investments from Grok Ventures, and bipartisan backing through the 2025 Infrastructure Investment and Jobs Act. Antora Energy CEO Andrew Ponec noted the site’s strategic location on the MISO power grid and proximity to POET’s plant and Otter Trail Power Co. as key factors in its selection. The technology aims to reduce fossil fuel reliance by enabling greater storage of renewable energy. The facility will improve grid efficiency by balancing supply and demand, ensuring excess wind energy is utilized rather than wasted. It also aligns with broader efforts to integrate renewable energy sources into the power grid.