Yes, in fact they're already in use. They're called pumped storage systems, https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.o

Yes, in fact they're already in use. They're called pumped storage systems, https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricity https://en.wikipedia.org/wiki/Pumped-storage_hydroelectricit...