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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. 
Make a 2 tier damn where the second hydro plant powers a pump to make the water go all the way to the top
I'm not following.
There's no such thing as free energy; losses due to friction would make this less efficient than the one-tier system