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. 
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.
You don’t really need huge volumes of water, a 5GW hydro storage proposal in Australia will require 38 gigalitres, or 0.038 cubic kilometres. At a depth of ten metres, that’s a 2km circle (or rather, two ~1.5km circular reservoirs).
Arizona uses ~8500 gigalitres a year to put that in comparison.