These are cool ideas but there's always an asterisk.
The issue here is: the "stored energy" isn't electricity, but heat. Converting heat into electricity is quite wasteful.
The issue here is: the "stored energy" isn't electricity, but heat. Converting heat into electricity is quite wasteful.
And if it’s very cheap, does it matter if the conversion is wasteful?
The question is about conversion is, is it still cheap if you add a powerplant (i.e. converting heat into electricity) and have to maintain it (moving parts, in contrast to batteries).
It's a crucial complement for batteries. Batteries suck for seasonal storage.