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.
There's also a version of this where you divert water at a regular hydro plant into a storage canal. It still uses pumps, but it doesn't need a separate turbine and a mountain.