Hot Stuff: Thermal Batteries Are Turning Heat Into Power
Snagging the Energy Slipping through the Cracks
As the world grapples with the twin challenges of rising energy demand and urgent climate goals, one of the biggest puzzles we face is how to store and distribute energy more efficiently. A surprising hero has emerged in this story: heat. More specifically, the kind of heat that’s usually lost in the industrial process – and a new generation of “thermal batteries” that promises to capture and reuse it.
The Problem: Wasted Heat Is Wasted Energy
Manufacturing everything from cars to packaging relies on vast amounts of heat, most of it generated by burning fossil fuels. Unfortunately, a staggering 20% to 50% of that industrial energy ends up lost as waste heat, according to the U.S. Department of Energy. That heat escapes into the environment through exhaust gases, cooling systems, and hot surfaces, meaning a huge chunk of energy (and money) literally goes up in smoke.
Industries have long sought ways to improve efficiency by capturing this wasted energy. Steelmakers, for instance, have been doing it for over 200 years. But with today’s growing energy demands and the shift toward renewable energy, the challenge now is to store heat reliably. And that’s where thermal batteries come in.
The Innovation: Thermal Batteries Break Through in 2024
While solar and wind power have become more affordable, they are also inconsistent. What happens when the sun doesn’t shine or the wind doesn’t blow? Energy storage becomes crucial. In 2024, MIT Technology Review named thermal batteries one of the year’s top Breakthrough Technologies, recognizing their potential to provide clean, cost-effective backup power.
How They Work: From Electricity to Stored Heat
Here’s the science in simple terms. When there’s a surplus of electricity, often from renewable sources like wind and solar, it can be converted into heat using a method called resistive heating. The electricity flows through materials with high electrical resistance, like graphite or metal alloys, generating intense heat.
This heat is then stored in heat-retaining materials such as bricks, crushed rock, or molten salt inside insulated containers. When energy is needed – say, to power a factory or heat a building – the stored thermal energy can be released on demand.
According to RMI, a nonprofit energy research group, this approach not only balances energy loads but can also drastically cut fossil fuel use in industries.
Real-World Applications: From Hospitals to Distilleries
Thermal batteries are no longer just a concept – they’re already in action. Some hospitals are using them to store renewable energy for heating. And in a headline-making move, a Kentucky whiskey distillery will soon host thermal batteries as part of a federally funded pilot project. The goal is to decarbonize operations by replacing natural gas boilers with renewable-powered heat batteries, thereby reducing greenhouse gas emissions and enhancing energy efficiency.
In March 2024, the U.S. Department of Energy committed $75 million to support this initiative, aiming to demonstrate how thermal energy storage can reduce industrial emissions.
Companies Leading the Charge
Several companies are pioneering different forms of thermal battery tech:
- Antora Energy uses carbon blocks to store heat.
- Brenmiller Energy employs crushed rock for thermal storage.
- Rondo Energy focuses on integrating heat storage into industrial systems.
- Electrified Thermal Solutions and Malta Inc. are exploring solutions involving molten metal and salt, respectively.
Some firms aim to embed thermal batteries directly in industrial sites, while others are developing large-scale systems for utilities, helping to stabilize electrical grids.
Challenges Ahead – And Why It Matters
Expanding this technology won’t be easy. Industries tend to be conservative about adopting new methods, and companies must both educate customers and prove that thermal storage systems are reliable and cost-effective.
Still, the pressure is on. The industrial sector is the largest source of greenhouse gas emissions globally and as demand for industrial heat continues to rise, cleaner solutions are no longer optional.
Thermal batteries offer a way forward: capturing wasted energy, reducing emissions, and keeping the lights (and machines) on – even when the wind stops blowing.
