When thermal battery maker Antora Energy announced it had raised $550 million in Series C funding late last month, the company also newly emphasized the potential of data centers as customers.
“The Series C advances the company’s work to deliver affordable, reliable energy at the scale and speed that American industry and data centers require,” Antora said in a statement, which mentioned data centers a total of five times. The company’s 2024 announcement of its $150 million Series B, meanwhile, didn’t mention them at all.
For a company that has yet to announce any data center deals, the emphasis is interesting — particularly because there’s something counterintuitive about installing a heat battery at facilities known for their cooling requirements. Isshu Kikuma, energy storage analyst at BNEF, pointed out that heat batteries’ most immediate byproduct is, in fact, heat, which makes them well-suited for industries requiring industrial heat, such as steel, cement, and chemicals.
“In terms of synergy, [thermal battery makers’] ideal customer would be the industrial players,” Kikuma said.
But as Justin Briggs, Antora’s co-founder and chief operating officer, told Latitude Media, delivering heat directly is just “option one.” “Option two is take that stored heat, convert it back into firm, reliable, cost-effective electricity,” he said.
At the moment, the customer of choice for that type of electricity is the booming data center market. Antora is among just a few thermal battery makers marketing their products to the sector, claiming they can provide the long-duration discharge that the market needs, and at the speed it needs new capacity. Others include Tempo Energy, until recently known as Redoxblox, which is reportedly raising a $40 million Series B while targeting data centers as new customers; and Rondo Energy, which has been pitching itself to the sector for over a year.
None of these companies have announced major data center partnerships yet. And more broadly, while storing heat is an old and well-understood science, no one has commercialized heat batteries at a large scale yet. Up until recently, the demand for long-duration clean storage to decarbonize industrial heat and back data center loads wasn’t high enough for most investors and industrial customers to confidently sign on to deals with first-of-a-kind technologies.
But the changing rhetoric of companies like Antora and Tempo signals that thermal battery makers “don’t want to miss out on the growing opportunities around data centers,” Kikuma said. It comes at a time when hyperscalers and other data center developers are striking deals for long-duration storage; the companies leading the market include Energy Dome, which has a partnership with Google for its CO2 batteries, and Form Energy, which has partnerships with both Google and Crusoe, among others, for its iron-air batteries.
Speed to power and long duration
When it comes to heat batteries, the main draw for data centers is speed to power, according to Briggs.
In May 2026, Antora announced it had deployed a five-gigawatt-hour energy storage system at a South Dakota bioprocessing facility owned by the biofuel producer POET. “It’s one of the largest batteries in the world, and we took that from an empty lot to delivering energy to the customer in under one year,” Briggs said. “There are not a lot of options for data centers to turn on at this fast. When data centers come to us, they’re telling us that they’re really excited because of how fast we can move.”
But there are other ways that the batteries could make sense as well.
Most heat batteries work by connecting modules made of cheap storage materials to the grid, and collecting power when electricity is cheap and abundant. That electricity is stored as heat, which can then either be delivered as heat, or else converted back into electricity via traditional heat-to-power technologies such as steam turbines.
Antora, for example, stores heat in blocks made of carbon material, while competitor Tempo uses a mixed metal oxide ceramic. Antora already has its first full-scale project active in South Dakota. Meanwhile, Tempo’s first two installations — an industrial-heat pilot at a Dow Chemical facility in West Virginia, and a demonstration project in San Diego to convert steam into electricity, in collaboration with EPRI — are slated for early 2027.
Both companies pack their cells into modules the size of shipping containers, which can be deployed next to a customer’s site and are heavily insulated so that very little heat escapes to surrounding equipment.
As Pasquale Romano, CEO of Tempo Energy, explained, the company’s batteries work the same regardless of the customer. If a customer needs to convert the stored heat back into electricity, they can deploy steam turbines. While Romano acknowledged that that’s an additional piece of equipment that needs to be installed, he said steam turbines are the equivalent of an inverter in a lithium-ion battery, and that they work thanks to “well-known science.” In some cases, the turbines’ exhaust itself can be used to operate an absorption chiller, Romano added, which provides cooling using heat instead of mechanical power, and could theoretically offset part of a data center’s cooling needs.
Plus, Antora’s batteries discharge for up to 100 hours, while Tempo is based on cycles of 12 to 24 hours — both far longer than what lithium-ion batteries achieve.
In a data center installation, these durations make them “really complementary to lithium-ion batteries, which can deliver a few hours of power and provide a really excellent service to the grid,” Briggs said. Both Briggs and Romano say their thermal batteries can be cheaper than other alternatives on the market — though they declined to share prices — mostly because the storage materials are inexpensive.
“The supply chain’s simple; the stuff is earth-abundant, it’s available everywhere,” Romano said, noting that it’s a different supply chain than lithium-ion technologies, and therefore additive and less at risk of bottlenecks.
Briggs agreed, noting that the supply chain is mostly domestic and rooted in U.S. manufacturing. “It’s a form of energy security,” Briggs said. “Our destiny is in our own control, which our customers really appreciate and view as an advantage as well.”
