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.
Why would the range of places shrink over time?
Because the alternatives get better.
What alternatives at that scale?
Batteries and synthetic fuels?
Did you read the post you're replying to?
I find reading interferes with the posting
I don't think batteries are designed for the duration of storage you want a backup of pumped hydro for, and it will remain to be seen what a synthetic fuel industry looks like (and whether it would ever be cost competitive with pumped hydro at the places where pumped hydro is currently viable).