Comment by johanyc

You need a reliable source for energy. Pumped storage is not. They are mostly good for dealing with the fluctuations of energy supply and demand. It crucially requires water to operate. You can't do much when there's a drought. Also, did some googling. The world’s largest pumped‑hydro storage plant (Fengning, China) stores nearly 40 GWh, delivering 3.6 GW for about 10.8 hours when full. Thats not even a day.

There are really three options for reliable baseload: coal, gas, nuclear. Pick your poison.