Firebrick thermal energy storage could reach 170 GW in the US by 2050

Firebrick heat storage for industrial processes could substitute for around 14% of battery capacity worldwide by 2050 in a 100% renewable energy system, compared to a base case without firebricks, according to a study by Stanford professor Mark Jacobson and three Stanford colleagues.

Firebricks are made from common materials and the cost of a firebrick storage system is less than one-tenth the cost of an equal-capacity battery system, the study says. Firebricks may be heated to high temperatures with external resistance heaters while a type of firebricks that are electrically conductive may be heated with an electric current that dissipates heat.

The US Department of Energy may provide up to $75 million to support two firebrick heat storage projects, and has said the technology is “highly replicable.”

Firebrick systems powered by renewable energy could be used for up to 90% of industrial process heat applications, the Stanford study says. Meeting that demand in the United States would require a firebrick system capacity of 2.6 TWh, with a peak discharge rate of 170 GW.

Producing industrial heat with renewables would reduce industrial combustion emissions, which are currently 9.6% of US all-sector emissions.

Globally, firebrick systems for industrial process heat could reach 2.1 TW of maximum power discharge capacity under a 100% renewable energy system, the study projects.

At that scale, firebrick systems would not only substitute for 14% of battery capacity but would also reduce annual hydrogen production for grid electricity by around 31% and underground heat storage capacity by around 27%.

Cost comparison

The present value cost of firebrick heat storage capacity will be $6/kWh of equivalent electricity over the 2020 to 2050 period, the study says.

That cost projection begins with a projected 2035 cost for a battery system. An installed battery pack will cost about $60/kWh, or $240/kW for four-hour batteries, by 2035, the study projects, and uses that value for the period from 2020 to 2050. The study notes that prices in 2035 may be lower than $60/kWh, citing a report that lithium-iron-phosphate battery pack prices from Chinese producers CATL and BYD cost around $56/kWh in January 2024.

The study next uses an estimate from firebrick system developer Rondo Energy that the cost per kilowatt-hour-thermal of a firebrick system will be around one-tenth the cost per kilowatt-hour-electricity of a battery system.

Because one-tenth of $60 is $6, the study uses in its analysis a $6/kWh cost for firebrick systems.

The study also cites a 2019 study saying that preliminary cost estimates at that time indicated a firebrick system cost nearly $10/kWh.

The open-access article, published in PNAS Nexus, is titled “Effects of firebricks for industrial process heat on the cost of matching all-sector energy demand with 100% wind–water–solar supply in 149 countries.”

From pv magazine USA.