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.
It seems like you’d lose a fair bit of energy from powering the pump and from the turbine not capturing 100% but I don’t actually know how it compares to other types of energy storage.