[phh]

Well you can't really do -600C sand (or anything), so the benefits of sand VS water largely diminished. "just" freezing water already gives you around 300C equivalent of sand (if my napkin is correct).

Also the point of this plant is to exploit the counter-correlation of cheap electricity and cold. Usually there is a bigger correlation between cheap electricity and heat.

[Gravityloss]

You can use heat to create cool by using absorption materials. It's of course way more complicated than with heat. But anyway with that, stored heat in sand could be used to create district cooling.

[dzhiurgis]

> you can't really do -600C sand (or anything)

You can if you stagger AC/HP or even peltier elements.

[myrmidon]

You misunderstood-- temperature is physically limited to -273°C, this is not an engineering problem. You have a smaller usable temperature range in a "cold storage" than with heat from fundamental physics alone.

[dzhiurgis]

Damn you got me there!