But why is it a great idea if solar provides more power, more cheaply without any danger whatsoever?
One of my favorites is pumped storage hydro.
There's no such thing as a free lunch.
Sure, solar isn't free, but most of the problems it faces aren't exactly insurmountable. In fact, we are already seeing those solutions being deployed in the world - mostly for economic reasons.
Sodium batteries are available these days. No rare minerals, non-flammable, almost fully recyclable.