[thingstodo]

Originally Posted by samwichse

Modern pumped hydro uses reversible turbines. No separate pumping system is used.

https://voith.com/corp-en/11_06_Bros...ge_einzeln.pdf

Engineering is all about trade-offs. It appears that the costs of doing separate pumps and turbines on very large systems out-weigh the increased efficiencies (from the graphs in the link)

I am guilty (again) of ASSUMING and being too LAZY to look it up