Yes, also it doesnt technically have to be sand, there are concrete mixes and even just bedrock that can be used for similar purposes. I've been looking at sand batteries myself for this reason: run the battery hot when power is cheap, let it cool when not.

This sort of thing is of course why it's useful to have a market mechanism for energy, it can encourage us to build environmentally friendly solutions.

[–] evranch@lemmy.ca 1 points 5 months ago (1 children)

Actually a modern "sand battery" does have to be sand or at least a granular material. The difference between a sand battery and thermal mass is that you use a conveyor to superheat small fractions of the sand, allowing the isolation of high grade heat.

If you have a single kWh to store and 1 ton of sand to work with, you could heat 1kg of sand to hundreds of degrees (sand battery), or 1 ton of sand by one degree (thermal mass).

1 ton of slightly warm sand is useless, while you can extract the high grade heat from the 1kg and get your 1 kWh back.

[–] wizzor@sopuli.xyz 1 points 5 months ago

Interesting, thanks for sharing that!