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 U.S. would require firebrick system capacity of 2.6 TWh, with a peak discharge rate of 170 GW.
The main advantage of using what is basically dirt is that it’s dirt cheap. You need a metric fuckton of this stuff so the cheaper the material, the better. Also, molten metal is difficult to handle.