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What do hexbears think about pumped hydropower storage?
(hexbear.net)
To make solar power viable, we need a solution for overnight energy storage.
Batteries are complicated.
Do you know what isn't? Water go up. 
Well, it's in a tank. Atop a 250m high tower. Smack in the centre of a ring of mirrors focusing all their heat on it. Liquified to generate steam.
I think the "corrosive" part is the least of the issues here.
Just something I’ve heard from some people about molten salt.