It's good but not perfect. Dams require a reservoir, which takes land out of use and changes the flow dynamics of a river. It can interrupt wildlife patterns both up and downstream. It introduces some risks of dam failure, and decommissioning a dam requires careful management of built up sediment. Flooded organic matter anaerobically produces methane.
It also requires significant space and particular configurations (must be on a river, must be in a hilly or mountainous area, etc.) It also isn't necessarily scalable -- how many more dams can we build?
You can build a crane and blocks or drill a big hole in lots and lots of places.
So yes, pumped hydro is better than fossil fuels. But also it's not something we can consider to be the ultimate solution to the issue of storage. By all means, let's use it (and we do use it today), but not stop there.
It also requires significant space and particular configurations (must be on a river, must be in a hilly or mountainous area, etc.) It also isn't necessarily scalable -- how many more dams can we build?
You can build a crane and blocks or drill a big hole in lots and lots of places.
So yes, pumped hydro is better than fossil fuels. But also it's not something we can consider to be the ultimate solution to the issue of storage. By all means, let's use it (and we do use it today), but not stop there.