May 2026 Update

5/18/26 UPDATE: THERMAL BATTERIES

Re: Chapter 3.5A STORING ENERGY WHEN THE SUN HIDES AND THE WIND DIES DOWN

Thermal batteries made of bricks that are heated electrically are gaining interest as an alternative to chemical batteries. If they reach high enough temperatures (~1,800 °C), they can deliver hot gas to run electrical turbines (instead of burning natural gas). So excess electricity can be stored for later use. High-temperature thermal batteries can also supply industrial heat, e.g. for steel, glass, and cement making. Industrial heat accounts for approximately one-fifth of global energy consumption, with 89% generated by burning fossil fuels. MIT spin-off startup Electrified Thermal Solutions has developed a superhot (up to 1800 °C) battery with electrically heated metal oxide firebricks. San Antonio has the first commercial installation.¹ 

Storing heat at lower temperatures can also save energy. A 'sand battery' (electrically heated crushed rock) is being developed by Polar Night Energy to supply district heating in Pornainen, Finland, using grid electricity during low demand times.²

References

1.        Electrified Thermal Solutions. “Industrial Heat Goes Electric: Electrified Thermal Solutions Turns on First Commercial-Scale Joule Hive^TM Thermal Battery.” PR Newswire, January 23, 2026.https://www.prnewswire.com/news-releases/industrial-heat-goes-electric-electrified-thermal-solutions-turns-on-first-commercial-scale-joule-hive-thermal-battery-302668926.html.

2.        Berdugo, Sophie. “We Went to Finland to Hear About the New 'Sand Battery' That Will Turn Stored Renewable Energy Back Into Power for the Electrical Grid.” Live Science, April 6, 2026. https://www.livescience.com/technology/engineering/we-went-to-finland-to-hear-about-the-new-sand-battery-that-will-turn-stored-renewable-energy-back-into-power-for-the-electrical-grid.