Finding
Thermal batteries turn cheap hours of wind and solar into round-the-clock industrial heat, and reached gigawatt-hour scale in 2026
A thermal battery heats bricks, crushed rock or carbon blocks with electric resistance when power is cheap, then delivers steam or hot air on demand. It never converts heat back to electricity, so it skips the step that makes electric heat expensive: it buys only the cheapest hours, and its storage medium costs a fraction of a lithium-ion battery per kWh.
The scale jumped in 2026. Antora commissioned a 5 GWh system at POET's Big Stone ethanol plant in South Dakota, raised a $550 million Series C and announced a 5.8 GWh project in Kansas. Rondo, after its 100 MWh unit in California, broke ground on 100 MWh at Covestro's Brunsbüttel chemical site in Germany and put a 32 MWh battery into a Thai cement plant. Electrified Thermal Solutions won an order from Holcim for heat at up to 1,800 °C. Several sell heat as a service: the developer owns the battery and the customer pays per unit of heat.
The economics depend on the power market more than on the hardware. Grids with many low-price hours - wind-heavy Texas and the Plains, solar-heavy California - give a thermal battery the most cheap charging, and ERCOT's frequent low and negative prices make Texas industrial sites natural candidates. China already runs the same idea at utility scale: molten-salt storage at its concentrating solar plants, now being adapted for industrial steam.
Companies
Thermal battery makers
| Company | Country | Technology | Projects |
|---|---|---|---|
| Antora Energy | US | Carbon blocks, to ~2,400 °C stored | 5 GWh at POET Big Stone, South Dakota (commissioned 2026); 5.8 GWh planned at a Kansas ethanol plant |
| Rondo Energy | US | Brick heat battery, to ~1,500 °C | 100 MWh at Holmes Western Oil, California; 100 MWh at Covestro Brunsbüttel (2026); 32 MWh at a Thai cement plant |
| Electrified Thermal Solutions | US | Conductive firebrick, to ~1,800 °C | 20 MWh unit (2026); Holcim order for two batteries |
| Kraftblock | Germany | Granular ceramic storage | Industrial steam and hot air |
| Brenmiller Energy | Israel | Crushed-rock storage (bGen) | Steam for food and beverage plants |
| EnergyNest | Norway | Concrete-based thermal storage | Steam storage for process plants |
| Kyoto Group | Norway | Molten-salt heat battery (Heatcube) | Industrial steam |
Compared
Where a thermal battery fits
| Option | Delivers | Temperature | Notes |
|---|---|---|---|
| Thermal battery | Heat (steam, hot air) | Hundreds to ~2,000 °C | Above heat-pump range; shifts cheap power |
| Industrial heat pump | Heat | Up to ~200 °C | Highest efficiency, COP 3-5 |
| Electric boiler | Steam | Up to ~350 °C | Simple, but pays the hourly power price |
| Lithium-ion BESS | Electricity | - | Round trip back to power; costlier per kWh stored |
Sources
Sources and scope
- Scope
- Thermal energy storage that delivers industrial process heat
- Sources
- Energy Storage News; Antora, Rondo and Electrified Thermal Solutions announcements (2025-26); Net Zero Compare (October 2026)
- Updated
- October 2026