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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. 
Saltwater damages turbine blades very fast. Using saltwater would require some very different engineering for the turbine blades, which might not be worth the benefit of being able to use saltwater.