World’s Largest Thermal Energy Storage System Goes Live in South Dakota | Antora - News and Statistics
May 20, 2026 Antora, a thermal energy storage technology company headquartered in California, has deployed what is described as one of the globe's largest energy storage installations, situated in South Dakota. Project Big Stone Overview The firm is currently bringing online Project Big Stone, a 5 GWh multi-day storage system that relies on its proprietary thermal battery technology. This system is located at a biofuels production facility in Big Stone City, South Dakota, which is run by POET Bioprocessing. Full commercial operation is anticipated before the end of 2026. The installation is intended to boost the plant's operational efficiency and reduce its energy expenditures. Antora and POET have entered into a long-term heat purchase agreement, which Antora states offers the biofuel producer competitively priced, uninterrupted energy. Technology Details Antora's thermal batteries function by storing heat within solid carbon blocks. Carbon is plentiful, inexpensive, highly energy-dense, and possesses strong thermal conductivity. The charging process involves using electricity to resistively heat these blocks; their high thermal conductivity allows for rapid charging. The blocks can retain heat at temperatures reaching 2,400 degrees Celsius, a level sufficient to meet continuous industrial heat requirements for several days. Furthermore, Antora has created thermophotovoltaic technology capable of converting the light emitted by the heated carbon blocks back into electricity. Thermal energy storage has the potential to cut a substantial portion of worldwide greenhouse gas emissions originating from industrial heating and cooling. It also enables factories and processing plants to charge their storage systems when electricity prices are low or to draw power directly from on-site solar panels or other renewable sources, thereby lowering costs. Nevertheless, the elevated temperatures necessary for numerous industrial processes make emission reduction challenging, as they demand significant energy and an effective storage medium. Antora asserts that its technology reaches temperatures high enough to serve hard-to-abate sectors like steel and cement manufacturing. CEO Insights and Project Timeline In a blog post for the World Economic Forum published early in 2026, Antora's CEO and co-founder Andrew Ponec noted that when founding the company, he and his co-founders examined all types of battery technologies—from advanced lithium and sodium chemistries to methods using molten salt and iron. Ponec wrote that they discovered that the most affordable and scalable approach to storing vast amounts of energy involves heating abundant earthly materials. The Big Stone project advanced from groundbreaking to commissioning in under twelve months. Ponec highlighted in his blog that this rapid deployment makes thermal batteries an attractive option for AI data center developers, who value quick access to power. For this South Dakota initiative, Antora collaborated with electric utility Otter Tail Power to establish a specific electricity rate for POET. This rate enables the system to supply continuous power to the Big Stone facility without causing rate increases for the utility's other customers. Political and Market Context Local officials, including Senator Mike Rounds and Representative Dusty Johnson, have commended the project. Rounds stated that it will generate tangible economic benefits for South Dakota, create employment, and enhance domestic energy production. Johnson described it as a crucial investment in affordable, dependable energy, reinforcing South Dakota's contribution to America's energy independence. Although thermal storage still holds a minor share of the overall energy storage market, the past year has witnessed the development of multi-megawatt-hour projects across various industries and uses. Antora was initially covered by Energy-Storage.news in 2022, when it secured $50 million from investors such as Breakthrough Energy Ventures, Shell Ventures, and Grok Ventures. In 2024, the company raised $150 million in a Series B funding round, attracting new investors like Decarbonization Partners, a joint venture between BlackRock and Singapore's Temasek. The proceeds from that round, which brought Antora's total funding to $230 million, were allocated to expanding manufacturing capacity and commercial deployments, including the construction of a California factory. In early April 2026, the startup announced the completion of its manufacturing campus expansion, adding two new facilities adjacent to an existing plant in San Jose.
Source: IndexBox