HWBRIEF
Antora's first commercial scale heat battery just booted at a South Dakota ethanol plant, turning surplus wind power into process steam for industry.
Clean-energy startup Antora Energy has begun running its first 5 GWh thermal battery, one of the largest battery storage projects in the world when fully running, at Poet Bio's ethanol plant near Big Stone City, South Dakota. The system, an "enormous toaster" built from more than 200 insulated blocks of solid carbon, charges when surplus wind power is available and dispatches heat and process steam to the plant when it isn't.
Antora announced a $550 million Series C on July 30, 2026, co-led by G2 Venture Partners and Eclipse, with Ribbit Capital, Salesforce Ventures, Activate Capital, John Doerr, Westly Group, StepStone Group, and Liberty Mutual Strategic Ventures participating. Existing backers Decarbonization Partners, Breakthrough Energy Ventures, and Lowercarbon Capital also returned. The company says the round brings total corporate and project financing to roughly $1 billion and will fund a second U.S. factory.
The Big Stone City deployment sits behind the meter, paired with a novel Otter Tail Power tariff that pays Antora to charge during surplus renewable periods. The model is now being aimed at data centers and other heat-hungry industrial sites as U.S. grid strain and high industrial electricity prices block direct electrification. Antora is one of dozens of thermal-storage startups, including Rondo and Energy Dome, using carbon, ceramic brick, or crushed rock.
Eclipse partner Joe Fath and G2 partner Jake Tauscher framed the round as a vote in industrial heat, not a clean-energy sweep. CEO Andrew Ponec said the funding is needed because "American industry is running into a wall of power and heat constraints."