This sounds pretty novel. It uses surplus green energy of electricity to heat a tank of sand that can then be used to heat anything that needs to be heated. The company is called "Polar Night Energy" and it is based in Finland. There is already one plant in production. The inventors and managers:

https://www.smart-energy.com/storage/first-commercial-scale-sand-battery-goes-online-in-finland/

Markku Ylönen, Polar Night Energy´s CTO, stated that the sand battery can, in addition to helping reduce emissions from district heating, transform it into an energy source that does not rely on combustion.

read your post and keep up with current events thanks to the information you provide, but today's post stands out. Smmheart

edited by a passing Kid who removed a disguised spam link.

Another new profile! And still spamming ones self. lol