Antora Energy is building a low-cost thermal battery for grid-scale energy storage to meet the growing need for long-duration storage created by the global transition to renewables.

Most chemical battery technologies, such as lithium-ion, can only store enough energy for a few hours of power. Antora’s technology, however, can discharge for days.

Antora’s energy storage technology, now in prototype form, is a “heat battery.” It stores energy very cheaply in the form of carbon blocks, which are insulated to retain their high temperatures, up to 2,000 degrees Celsius. A special type of solar cell that can convert heat to electricity is used to draw off the power when needed.

To develop its prototype, the company worked through the U.S. Department of Energy’s Advanced Research Projects Agency-Energy program and the Cyclotron Road incubator at Lawrence Berkeley National Laboratory. Through the Shell GameChanger Accelerator Powered by the National Renewable Energy Laboratory (NREL), Antora’s founders can further develop the special solar cells that convert heat into electrons.

Even at this early stage, Antora estimates their energy storage costs as less than 1/20th of other conventional battery technologies. Excess electricity—such as midday solar energy—is stored in the batteries through simple resistance heating.

“This is a game changer,” says Antora’s Chief Technology Officer Justin Briggs. “What we are doing is really targeting a technological white space.”

This GCxN project builds off an existing collaboration between the company and NREL researcher Myles Steiner, who has helped develop the photovoltaic cells that turn heat into electricity.

With support from the GameChanger program, Antora will use NREL’s lab equipment to grow larger thermal photovoltaic cells  to move its technology towards commercialization and scale-up.

“We feel incredibly lucky and very privileged to be a part of GameChanger at the early stage,” Briggs says. “Antora Energy is really on a mission to create a clean-energy future, and we think that long-duration storage to support wind and solar on the grid is the key to doing that.”