Firebricks offer low-cost storage for carbon-free energy

Firebricks, designed to withstand high heat, have been part of our technological arsenal for at least three millennia, since the era of the Hittites. Now, a proposal from MIT researchers shows this ancient invention could play a key role in enabling the world to switch away from fossil fuels and rely instead on carbon-free energy sources.

The researchers’ idea is to make use of excess electricity produced when demand is low — for example, from wind farms when strong winds are blowing at night — by using electric resistance heaters, which convert electricity into heat. These devices would use the excess electricity to heat up a large mass of firebricks, which can retain the heat for long periods if they are enclosed in an insulated casing. At a later time, the heat could be used directly for industrial processes, or it could feed generators that convert it back to electricity when the power is needed.

The technology itself is old, but its potential usefulness is a new phenomenon, brought about by the rapid rise of intermittent renewable energy sources, and the peculiarities of the way electricity prices are set. Technologically, the system “could have been developed in the 1920s, but there was no market for it then,” says Charles Forsberg, a research scientist in MIT’s Department of Nuclear Science and Engineering and lead author of a research paper describing the plan, that appears this week in the Electricity Journal.

Forsberg points out that the demand for industrial heat in the U.S. and most industrialized regions is actually larger than the total demand for electricity. And unlike the demand for electricity, which varies greatly and often unpredictably, the demand for industrial heat is constant and can make use of an extra heat source whenever it’s available, providing an almost limitless market for the heat provided by this firebrick-based system.

Continue reading at MIT.

Photo via MIT.