Holcim Integrates Two Joule Hive Thermal Batteries Into Its Cement Making Facility

Cement giant Holcim has installed two "Joule Hive" thermal batteries at one of its production facilities, using technology from MIT spinoff Electrified Thermal Solutions. The batteries are made of specially formulated firebricks that conduct electricity and can heat up to 1800°C, hot enough for the industrial processes that make cement, steel, and glass. Until now, those processes required burning fossil fuels because electricity alone couldn't generate that much heat. The bricks can store heat for up to three days and run at 95 percent efficiency, making them a way to use excess renewable electricity productively.

This isn't a home technology, but it points to how heavy industry is starting to shift away from fossil fuels for high-heat manufacturing, cement production alone accounts for roughly 8 percent of global carbon dioxide emissions. The Holcim installation follows more than 1,000 hours of testing at a commercial-scale unit in San Antonio. A similar project is also underway at an Ashland chemical plant in Calvert City, Kentucky, backed by up to $35 million in matching Department of Energy funds, where the batteries will eventually replace methane-fired boilers used to generate steam.

None of this changes what's available for home upgrades or rebates. It's industrial-scale technology aimed at decarbonizing factories, not houses. But it reflects a broader trend of electrification replacing fossil-fuel combustion across the economy, the same shift driving heat pumps and electric appliances into homes.