- Antora Energy closed an oversubscribed $550M Series C co-led by G2 Venture Partners and Eclipse, bringing total funding to $770M since 2017. [1] - New investors include Salesforce Ventures, Ribbit Capital, John Doerr, and Liberty Mutual Strategic Ventures alongside existing backers Breakthrough Energy Ventures and Lowercarbon Capital. [2] - The company is commissioning a 5 GWh thermal battery system at a POET bioprocessing facility in South Dakota — one of the world's largest battery storage projects. [3] - Funds will go toward accelerating U.S. project deployments, expanding production capacity, and establishing a second domestic manufacturing hub.
[2] Antora Energy, a San Jose-based thermal battery startup, has closed a $550 million Series C funding round, one of the largest cleantech raises of 2026. The oversubscribed round was co-led by G2 Venture Partners and Eclipse, with participation from Salesforce Ventures, Ribbit Capital, Breakthrough Energy Ventures, Lowercarbon Capital, and Kleiner Perkins chairman John Doerr, among others. [1][2]
The raise brings Antora's total funding to $770 million since its founding in 2017 and arrives as surging electricity demand from AI data centers has created acute energy bottlenecks across the United States. [1] Antora's technology stores cheap renewable electricity as heat in solid carbon blocks at temperatures up to 2,400°C, then releases it on demand as usable heat or power — without relying on critical minerals or lengthy construction timelines.
[3]The company plans to use the capital to accelerate large-scale U.S. project deployments, expand its San Jose manufacturing campus — already one of the nation's largest battery gigafactories — and establish a second domestic manufacturing hub. [2]
The Round #
The $550 million Series C was co-led by G2 Venture Partners and Eclipse. New investors joining the round included Ribbit Capital, Salesforce Ventures, Activate Capital, Westly Group, StepStone Group, and Liberty Mutual Strategic Ventures. [2]
Existing backers Decarbonization Partners — a joint venture between BlackRock and Temasek — along with Impact Science Ventures, Trust Ventures, Breakthrough Energy Ventures, and Lowercarbon Capital also participated. [1] [2] The round was oversubscribed, though Antora did not disclose its post-money valuation.
[3]## The Technology Antora's thermal batteries use electricity to resistively heat solid carbon blocks, which have high thermal conductivity for fast charging. The carbon stores heat at temperatures up to 2,400°C, and energy can remain stored for multiple days to serve continuous industrial demand. [3]
The company has also developed proprietary thermophotovoltaic technology that converts light emitted from the heated carbon back into electricity, giving customers flexibility to draw energy as either heat or power. The system avoids dependence on lithium, cobalt, and other critical minerals used in conventional battery chemistries. [3]
The Flagship Project #
Antora's marquee deployment is a 5 gigawatt-hour thermal energy storage system at a POET Bioprocessing facility in South Dakota, which began commissioning in May 2026. The project, comprising more than 200 individual thermal batteries, advanced from initial construction to delivering energy in under 12 months. [3]
When fully operational, it will rank as one of the largest battery storage installations in the world. The project serves as a proof point for Antora's ability to deliver utility-scale storage on compressed timelines — a key selling proposition for hyperscalers and industrial operators facing years-long grid interconnection queues. [1][3]
Market Context #
The round lands amid an intensifying race to power AI infrastructure. U.S. data center electricity consumption has surged as hyperscalers including Microsoft, Google, and Amazon expand capacity for training and inference workloads. Grid constraints and permitting delays have made behind-the-meter energy solutions increasingly attractive. [1]
Antora targets both data center operators and heavy industrial customers, positioning thermal storage as a complement to renewables that can deliver round-the-clock power. The company's San Jose manufacturing campus has expanded into a three-building facility that it describes as one of the nation's largest battery gigafactories. [2]
What's Next #
With the Series C capital, Antora plans to establish a second U.S. manufacturing hub and strengthen its domestic supply chain, signaling plans for a significant production scale-up. [2] The company's pipeline targets additional large-scale deployments across the country, serving both the data center and industrial decarbonization markets.
[1]Thermal energy storage remains a relatively small segment of the broader energy storage market, which is dominated by lithium-ion batteries. But Antora's ability to attract top-tier venture capital — and deliver a multi-gigawatt-hour project in under a year — suggests growing investor conviction that the technology can carve out a meaningful niche in the AI power buildout. [1][3]
Further sources #
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