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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. 
There are actually many examples! A recent one with good English copy is here: https://www.scmp.com/news/china/science/article/3225408/china-worlds-largest-hybrid-solar-hydro-plant-produces-electricity-tibetan-plateau