Key Takeaways
- 1A new category of energy storage startups is heating ordinary refractory brick to 1,000°C using excess renewable electricity, storing that heat, and recovering it later as heat or electricity — a technology sometimes called a 'thermal battery' or 'firebrick resistance-heated energy storage' (FIRES) system.
- 2The core insulating and structural material in these systems is standard high alumina or insulating refractory brick — the same product category refractory traders already stock, sold into an entirely new industry.
- 3Advantages over lithium-ion for industrial heat applications: no degradation cycles, no rare-earth dependency, decades-long service life, and dramatically lower cost per kWh of thermal capacity stored.
- 4Target customers are steel, cement, and power plants looking to decarbonize process heat, plus renewable energy developers needing grid-scale storage that isn't lithium.
- 5This is a genuinely new refractory market with almost no supplier-side content addressing it — an early-mover content and relationship opportunity for traders willing to engage before it becomes obvious.
Storing Energy as Heat, Not Electrochemistry
A growing category of energy storage startups is heating refractory brick to around 1,000°C using excess renewable electricity, storing that energy in the brick's thermal mass, then recovering it later as heat or electricity — a technology called a "thermal battery" or firebrick resistance-heated energy storage (FIRES), built from the same high alumina and insulating refractory brick that refractory traders already stock. Unlike lithium-ion, the storage medium here doesn't degrade with charge cycles, doesn't depend on constrained raw materials like lithium or cobalt, and costs a fraction as much per kWh of thermal capacity — which is why it's gaining traction specifically for industrial process heat, an application lithium was never well-suited to in the first place.
How It Works
- Charging: Excess electricity (often solar or wind during periods of low grid demand) runs through resistive heating elements embedded in a refractory brick core, raising it to roughly 1,000°C.
- Storage: The heated brick mass, surrounded by insulating refractory to minimize losses, holds that thermal energy for hours to days depending on system design.
- Discharge: Heat is recovered either directly as process heat (steam generation, industrial drying) or converted back to electricity via a heat engine or turbine.
Why Refractory Brick, Specifically
| Property needed | Why refractory brick delivers it |
|---|---|
| High volumetric heat capacity | Dense high alumina or magnesia brick stores substantial thermal energy per unit volume |
| Thermal cycling stability | Refractory brick is engineered for repeated heating/cooling without structural degradation — the core requirement for daily charge-discharge cycles |
| Cost per unit capacity | Refractory brick is a mature, low-cost, high-volume manufactured product — a major cost advantage over battery chemistries |
| No resource constraints | Made from alumina, silica and magnesia — abundant materials, unlike lithium, cobalt or nickel |
What This Means for the Refractory Trade
This is a genuinely new customer category for refractory suppliers — energy storage developers, not furnace operators — and almost no refractory trader has written anything addressing it yet. For a supplier willing to engage early, that means being the first credible answer when an energy storage engineer searches for refractory grade selection, thermal cycling data, or brick supply for a pilot thermal battery installation.
SAPL Supply for Thermal Energy Storage
Shanker Agencies supplies high alumina and magnesia refractory brick and insulating refractory systems suited to thermal energy storage applications, and can support energy storage developers on grade selection for repeated high-temperature cycling duty. Submit an RFQ with your temperature range and cycling requirements, or see our shaped refractories range.
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Frequently Asked Questions
What is a thermal battery?
A thermal battery (also called firebrick resistance-heated energy storage, or FIRES) stores energy as heat rather than electrochemically. Excess electricity — often from solar or wind during low-demand periods — heats a mass of refractory brick to around 1,000°C using resistive heating elements. The heat is retained in the brick's thermal mass and later recovered either as process heat directly or converted back to electricity via a heat engine or turbine.
What refractory materials are used in thermal batteries?
The core storage medium is typically high alumina or magnesia-based refractory brick, chosen for high heat capacity, thermal stability at repeated heating cycles, and low cost relative to exotic storage media. Insulating refractory (ceramic fibre, insulating firebrick) surrounds the hot core to minimize heat loss during storage.
Why are companies choosing thermal batteries over lithium-ion for industrial heat?
For process heat applications — as opposed to mobile or grid-frequency applications lithium suits better — thermal batteries offer several advantages: refractory brick does not degrade with charge cycles the way lithium chemistry does, there's no dependency on lithium, cobalt or other constrained materials, service life is measured in decades rather than years, and cost per kWh of thermal storage capacity is substantially lower than electrochemical batteries.
Which industries are the customers for thermal battery technology?
Primary customers are industries with continuous high-temperature process heat needs looking to decarbonize — steel reheating, cement, and other process industries — plus renewable energy developers building grid-scale storage that doesn't rely on lithium supply chains. As industrial decarbonization mandates tighten, this segment is expected to scale meaningfully.
Does SAPL supply refractory brick for thermal energy storage applications?
Yes. Shanker Agencies supplies high alumina and magnesia refractory brick along with insulating refractory systems suited to thermal energy storage applications, and can work with energy storage developers on grade selection for repeated high-temperature charge-discharge cycling.