Thermal batteries could transform renewable energy storage and provide a cheaper and scalable alternative to lithium-ion technology.
“Intermittent wind and solar power are becoming the cheapest forms of energy that humans have ever known, and all kinds of energy storage is now being used to harness that, to drive transportation, to drive the electricity grid,” said John O’Donnell, the founder and chief innovation officer of Rondo Energy. “Heat batteries are a fundamentally new way of storing energy at a small fraction of the cost.”
Heat batteries store excess electricity as heat in materials like bricks or graphite, which can reach temperatures over 3,000 degrees Fahrenheit. The stored heat can then be released when needed, making thermal batteries ideal for powering the manufacturing of steel, cement and chemicals
“What a thermal battery does is allow you to soak up clean, inexpensive electrons from wind and solar, store them as heat and deliver that energy later to an industrial customer,” said Justin Briggs, COO of Antora Energy.
Rondo Energy is one of the leaders in this space. The company built its first commercial heat battery in California’s Central Valley at Calgren Renewable Fuels.
The system stores solar energy during the day and delivers high-temperature heat 24/7.
“We use unrefined raw materials, like bricks made from clay,” O’Donnell said. “A pound of brick stores more energy than a pound of lithium-ion battery, at less than 10% of the cost.”
By 2027, Rondo Energy plans to expand production to 90 gigawatt-hours annually, a scale that could cut 12 million tons of carbon dioxide emissions per year. That’s the equivalent of taking 4 million gas cars off the road, according to the company.
Despite their promise, thermal batteries face hurdles, including high upfront investment and a lack of familiarity among industrial users.
“The biggest hurdle is educating the market that this technology is available,” O’Donnell said.
