This battery company from MIT helps factories ditch fossil fuels for cheap renewable power

Most factories still run on fossil fuels, whether they’re making potato chips or steel. But a new “thermal battery” could make it cheaper to do the same work with clean energy.

Electrified Thermal Solutions, a startup spun out from MIT research in 2021, just fired up a demo battery that can hit 1,800 degrees Celsius—hot enough to make steel, cement, or chemicals. The battery uses power from the grid to heat its custom bricks when electricity is cheap. When a factory needs hot air later, it’s provided by the superheated bricks.

It’s also cheaper to use than natural gas, so factories don’t need a climate goal to be convinced to make the switch.

“This is a cheaper approach to heat that today isn’t being taken advantage of,” says Daniel Stack, cofounder and CEO of Electrified Thermal Solutions. Electricity is already a cheaper heat source than natural gas, but in the past factories haven’t been able to feasibly use it with their equipment.

Some other startups are making similar thermal batteries, but can’t reach the highest temperatures needed by certain industries. Electrified Thermal’s tech, called the Joule Hive Thermal Battery, uses a unique conductive brick that electricity can flow straight through, enabling ultra-high temperatures.

Backers include ArcelorMittal, the world’s largest steelmaker, which could eventually use the technology to heat up equipment like blast furnaces.

The savings for industrial customers could be substantial. “We can charge up with the cheapest electricity during hours of low prices, and this can save you 15%, 20%, 30% on your heating bill,” Stack says. “These commodity industries live and die by the price they pay for their heating inputs.”

Both in the U.S. and Europe, wholesale electricity prices drop close to zero—or even negative prices—at certain times when renewable energy is abundant. The startup is focused first on Europe, where policy makes it easier to access that cheap electricity. (Even as electricity demand grows from data centers, Stack says that there will still be plenty of surplus electricity available at particular hours at a lower price.)

The tech is designed to be easily added to existing factories, with pipes connecting hot air from the batteries into existing kilns, boilers, or furnaces. Customers have the option to pay for heat as a service or buy the batteries directly.

The new demonstration system, at the Southwest Research Institute in San Antonio, will let potential customers see the equipment in action. Commercial units will begin rolling out to some customers later this year.

The batteries can easily scale up, Stack says, and are made from off-the-shelf materials. The bricks are similar to those used in glassmaking, and a large manufacturer, HWI, is beginning to mass manufacture them.

If industry at large makes the switch, the climate benefits would be huge. By one estimate, industrial process heat uses around 20% of the world’s energy. “We’re talking about massive emissions reductions—to the tune of several gigatons per year of CO2—reduced through this transition,” Stack says.

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