If your goal is to deliver clean heat to an industrial process, the instinct is often to reach for batteries. But for heat specifically, thermal energy storage usually wins on cost and fit. Here is the comparison that matters.
What each technology actually stores
A lithium-ion battery stores electricity as chemical potential. To turn that into process heat, you discharge the battery and run the electricity through a heater — and if you ever need electricity back, you accept another round of losses.
Thermal energy storage skips the detour. It stores heat directly in a medium such as molten salt or rock, and discharges heat on demand.
Head-to-head
| Dimension | Lithium battery | Thermal energy storage |
|---|---|---|
| What it stores | Electricity | Heat |
| Cost per kWh (capacity) | High | Low |
| Best discharge form | Electricity | Heat |
| Round-trip for heat | Lossy (elec → heat) | Direct |
| Typical lifetime | Degrades with cycles | Very long, stable |
| Materials risk | Critical minerals | Abundant, benign |
When to use which
- Choose batteries when you need fast, electrical discharge — frequency response, backup power, EV charging buffers.
- Choose thermal energy storage when the end use is heat — process steam, drying, district heating, preheating — and you want the lowest cost per stored kWh.
For a refresher on the fundamentals before deciding, start here:
The bottom line
Batteries and thermal storage are complements, not rivals. But when the job is industrial heat, storing heat directly — as IsoTES® does — is almost always the more economical path.