[jasoncartwright]

This is exactly how the 6th largest power plant in the UK works (but the turbine is reversed to become the pump)

https://www.youtube.com/watch?v=McByJeX2evM

https://electricityproduction.uk/plant/GBR1000151/

[uxp]

There's a number of them all over the world. Surprisingly simple idea and amazingly powerful storage.

https://en.wikipedia.org/wiki/List_of_pumped-storage_hydroel...