Industrial process heat accounts for roughly a quarter of global energy use and a comparable share of energy-related emissions. Most of that heat is currently delivered by burning fossil fuels — natural gas, coal, fuel oil, biomass — in boilers, kilns, and furnaces. The decarbonization challenge is not a power-sector challenge; it's a chemistry and combustion challenge with different physical constraints.
Among the credible decarbonization pathways, thermal energy storage — charging up materials with cheap renewable electricity and discharging the stored heat as process heat — has moved from research into early commercial deployment. The category goes by various names — heat batteries, thermal storage, sensible-heat storage — and includes a small group of companies whose technologies differ meaningfully despite the shared category label.
This piece examines the technology stack, the customer types writing the first commercial checks, and the constraints that will shape which approaches scale.
The technology approaches
Four broad approaches dominate the commercial-deployment frontier, each occupying a different point on the temperature-and-application spectrum.
Refractory-brick thermal storage, exemplified by Rondo, uses high-temperature firebrick as the storage medium. The bricks are heated to extreme temperatures by resistive electric elements during cheap-electricity hours, then deliver heat through air or steam discharge for industrial use. The advantage is high temperature capability (above 1,200°C in some configurations) and use of established, low-cost materials.
Carbon-block thermal storage, exemplified by Antora Energy, uses carbon as the storage medium. Carbon has favorable specific heat properties at very high temperatures and remains stable in inert atmospheres at temperatures above what refractories can sustain. Antora's system targets temperatures suitable for processes that current heat-storage approaches can't credibly serve.
Crushed-rock thermal storage, with variants from Brenmiller Energy and others, uses crushed stones or ceramic media at lower temperatures (typically below 600°C). The advantage is lower system cost and broader material availability. The constraint is application fit — many industrial heat applications need temperatures above what crushed-rock systems can deliver.
Molten salt storage, originally developed for concentrating solar power, has been adapted for industrial heat applications by several developers. Operating temperatures typically span 290-565°C, suitable for steam generation and a meaningful share of mid-temperature industrial applications.
These approaches are not directly competitive — they target different segments of the industrial heat demand curve.
Where temperature requirements drive technology fit
Industrial heat demand spans temperatures from below 100°C (some food processing, drying) through several hundred degrees (chemicals, refining, paper) to well above 1,000°C (cement, glass, steel, ceramics). Different applications have different temperature requirements, and no single thermal storage technology serves the entire spectrum cost-effectively.
For the lowest-temperature applications, electric heat pumps often outperform thermal storage on lifecycle economics — pumps deliver heat at COP greater than one, while thermal storage delivers at less than one (with electrical losses on charge and discharge).
For the mid-temperature applications, thermal storage starts to become genuinely competitive with on-demand electric heating because of the renewable-cost arbitrage. If renewable electricity is cheaper at off-peak hours than at peak hours, storing energy as heat at off-peak hours and discharging at peak hours captures real cost savings.
For the high-temperature applications — above 1,000°C — thermal storage is competing against industrial processes that have no viable electric heating alternative beyond electric arc, induction, or plasma. The decarbonization stakes are higher because the alternative pathway is sometimes simply unavailable.
Who's writing the first commercial checks
Three customer profiles dominate the early commercial deployments.
Chemical and process industry incumbents with credible decarbonization targets and large process heat demand. These customers have the scale to absorb pilot-deployment risk and the regulatory exposure (carbon pricing, disclosure requirements) to value emissions reductions properly. Several large chemical companies have signed offtake agreements with thermal storage suppliers.
Food and beverage manufacturers in markets with high electricity-to-gas price ratios for off-peak power. The thermodynamic match is good (most applications below 300°C) and the brand-value of decarbonized operations is meaningful in consumer-facing categories.
Cement and steel pilots, where the temperature requirements push the technology to its limits but where successful demonstration would unlock decarbonization pathways with no other commercially-credible options. These pilots are smaller in number but disproportionately important.
The economic logic that determines scaling
Thermal storage economics turn on three variables: the spread between off-peak and on-peak electricity prices, the cost of the heat storage system, and the cost of the alternative (typically natural gas).
The first variable has improved structurally over recent years. Power markets with high renewable penetration now exhibit consistent off-peak price collapses — sometimes to near-zero or negative prices — that are precisely the conditions thermal storage is designed to exploit. The wider the spread, the better the storage economics.
The second variable is improving through scale and engineering refinement, though not as rapidly as some early projections assumed. Materials costs are largely floor-limited; engineering and integration costs are where the cost curve has room to decline.
The third variable is harder to call. Natural gas prices have ranged widely over recent years, and the geographic dispersion of gas pricing is substantial. Where gas is cheap, thermal storage is harder to justify on pure economics. Where gas is expensive or carbon-priced, thermal storage is competitive today and increasingly so.
The framing for industrial decarbonization planners
Thermal storage has moved from research to commercial relevance. For industrial heat applications in temperature ranges and market conditions where the economics work, it's now a credible procurement option rather than a future technology.
But the category isn't a single solution; it's a family of approaches with different fit profiles. Procurement teams should evaluate technology selection against their specific temperature requirements, demand profile, and local power market structure rather than treating thermal storage as a generic option.
The most consequential question is no longer whether thermal storage works. It does. The question is which applications, which suppliers, and which market conditions support deployment at scale. That answer is being worked out commercially over the next several years.