[Wildbill22]

I live near the Ludington MI facility. At first they discovered it turned aquatic life, fish, into chum until they had to screen it all off.

There has to be a net loss in energy which can only be made up economically by the time of the day that it is used/stored. It is not an answer or a major source of energy. More like a science experiment.

[ProtectOurFreedom]

It is not an energy generation plant. It is an energy storage facility. It is about the only way you can store HUGE amounts of energy for serious periods of time. Batteries, flywheels, supercapacitors, CAES — none of these can store and release energy like pumped storage.

Wiki—> Pumped storage is by far the largest-capacity form of grid energy storage available, and, as of 2020, the United States Department of Energy Global Energy Storage Database reports that PSH accounts for around 95% of all active tracked storage installations worldwide, with a total installed throughput capacity of over 181 GW, of which about 29 GW are in the United States, and a total installed storage capacity of over 1.6 TWh, of which about 250 GWh are in the United States.

The first pumped storage facility was built in 1907. In the 1930s reversible hydroelectric turbines became available.

Of course there are round-trip losses. There are with every energy storage system. The round-trip energy efficiency of PSH varies between 70%–80%, with some sources claiming up to 87%.

”Science experiment”? Sure, you go on believing that.