Transitioning to 100% renewable energy globally could be more cost-effective and straightforward using firebricks, a form of thermal energy storage dating back to the Bronze Age, to provide the heat required for industrial processes, according to a new Stanford study. Modern industries demand high temperatures for manufacturing, achieved primarily by burning coal, oil, fossil gas, or biomass. With the global shift toward reducing emissions by moving away from fossil fuels to renewable sources like wind, solar, and hydro, a critical question arises: how can industries access on-demand continuous heat in a fully renewable world?
Researchers from Stanford’s Department of Civil and Environmental Engineering suggest that firebricks, an ancient solution, could be the answer. “By storing energy in the form closest to its end use, you reduce inefficiencies in energy conversion,” explained Daniel Sambor, a postdoctoral scholar and study co-author. The principle is simple: if you need heat for industry, store it in firebricks.
Refractory bricks, which can withstand high temperatures, have been used for millennia to line furnaces, kilns, fireplaces, and ovens. Similar to these, firebricks can store heat or insulate, depending on their composition. Ideal low-cost firebrick materials include alumina, magnesia, or low-grade graphite, known for their high specific heat and melting points. Insulating firebricks, often made from silica, have low thermal conductivity, preventing rapid heat loss.
Heat-storing firebricks are typically encased in more insulating firebricks and then in steel containers to minimize heat loss. Industries can draw process heat by passing air through channels in the bricks or using infrared radiation from the heated bricks. This method eliminates the need for battery or green hydrogen storage of renewable electricity.
The Stanford study examined the use of firebricks in 149 countries, responsible for 99.75% of global CO2 emissions, in a hypothetical 2050 scenario where they transitioned to 100% renewable energy. The researchers found that using firebricks could reduce capital costs by $1.27 trillion, decrease energy storage needs by 14.5%, lower annual hydrogen production by 27.3%, cut land requirements by 0.4%, and reduce overall annual energy costs by 1.8%.
“Firebricks offer a faster, lower-cost transition to renewables,” said Mark Jacobson, the study’s lead author. This ancient technology could play a significant role in reducing industrial emissions, making renewable energy adoption more affordable and efficient.