Firebricks, which are bricks designed to withstand high heat, have been around for more than 3000 years. The Hittites used them to line iron-smelting kilns. They are simply bricks made from clays that can withstand much higher temperatures than ordinary bricks.
A group of MIT researchers have proposed an energy storage technology based on firebricks. The idea is to make use of excess electricity produced when demand is low – for example, from wind farms when strong winds blow at night – to run electric heaters that heat up a large mass of firebricks. The bricks can maintain their heat for long periods of time if they are enclosed in an insulated casing. At a later time, the stored heat could be used directly for industrial processes, or it could be used to power generators that convert the energy back into electricity when the power is needed.
Some of the appeal of this idea comes from the fact that the demand for industrial heat in the U.S. and in other industrialized nations is actually larger than the total demand for electricity. Furthermore, the demand for heat is constant and predictable, unlike the demand for electricity.
Another compelling reason to pursue such a scheme is that the massive growth in renewable energy generation from sun and wind has led to instances when there is simply too much power being produced when demand is low leading to exceedingly low or even negative prices for the electricity. By diverting excess output into thermal storage in firebricks, producers can either sell the heat directly or produce electricity later when it is needed, thereby setting more realistic lower limits on the price of electricity.
An ancient technology may have a very modern application.
Photo, posted October 24, 2009, courtesy of Flickr.