That's a very poor article. It doesn't explain what the potassium chloride is for. It's interesting but you can store a lot of thermal energy in concrete. Th

That's a very poor article. It doesn't explain what the potassium chloride is for. It's interesting but you can store a lot of thermal energy in concrete. The heat capacity is 1050 J/(kg.K). One cubic meter of concrete is about 2 400 kg and the heat capacity is roughly 1 x 10^3 J/(kg.K) so raising the temperature by just 1 degree C would store 2.4 x 10^6 J. That's 666 Wh. Twice the energy storage for only one kelvin temperature rise with no technological breakthroughs needed. Granted it's not electricity but in temperate and colder climates a lot of the energy needed in a home is heat. Still a very interesting idea and if it can be made to work cheaply enough even at the storage capacity they quote it would add a lot of flexibility to the energy system.