For example, bricks to be placed in the center of the assemblage could have high thermal conductivity, so that they can easily take in heat from the resistance heaters.
Turning that heat back into electricity is a bigger technical challenge, so that would likely be a next-generation version of the FIRES system, he says.That's because producing electricity with the conventional turbines used for natural gas power plants requires a much higher temperature.A promising material for these firebricks is silicon carbide, which is already produced at massive scales for uses such as sandpaper.China currently produces about a million tons of it per year, Forsberg says.But the bricks used for the outer parts of the structure could have very low thermal conductivity, thus creating an insulating shell to help retain the heat of the central stack.
The current limit on FIRES is the resistance heaters.
At present, the options for storing excess electricity are essentially limited to batteries or pumped hydroelectric systems.
By contrast, the low-tech firebrick thermal storage system would cost anywhere from one-tenth to one-fortieth as much as either of those options, Forsberg says.
Existing low-cost, reliable heaters only go to about 850 C.
Ultimately, Forsberg suggests, the bricks themselves could be made electrically conductive, so that they could act as low-cost resistance heaters on their own, both producing and storing the heat.
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.