[chelical]

I don't understand why people don't talk about the water usage involved in pumped hydro when the vast majority of the Western United States is dealing with record low water levels + sinking due to groundwater usage.

[pfdietz]

Pumped hydro doesn't use up the water. It goes back and forth between the lower and the upper reservoirs. Some evaporates, for sure, but that's a tiny fraction of the water that would be evaporated cooling a NPP of the same power output.

[ncmncm]

Furthermore, putting floating solar on the reservoirs would eliminate much of the evaporation.

[chelical]

Sure it doesn't use water, but it's still taking water out of the ecosystem. Why is that not considered when we have record low water levels.

[ncmncm]

And, when it is used for storage, it is at higher altitude, so evaporates less.

[ben_w]

PV can be used to desalinate sea water as well as pumping it up to the top of the reservoirs. It's also possible to extract energy from fresh water as it mixes with sea water to improve the system efficiency, but I don't want to even guess if that's better or worse overall than just cleaning the water and reusing it.