'Water batteries' could store solar and wind power for when it's needed

https://www.npr.org/2022/10/14/ [login to see] /water-batteries-could-store-solar-and-wind-power-for-when-its-needed
The San Diego County Water Authority has an unusual plan to use the city's scenic San Vicente Reservoir to store solar power so it's available after sunset. The project, and others like it, could help unlock America's clean energy future.

Perhaps a decade from now, if all goes smoothly, large underground pipes will connect this lake to a new reservoir, a much smaller one, built in a nearby canyon about 1100 feet higher in elevation. When the sun is high in the sky, California's abundant solar power will pump water into that upper reservoir.

It's a way to store the electricity. When the sun goes down and solar power disappears, operators would open a valve and the force of 8 million tons of water, falling back downhill through those same pipes, would drive turbines capable of generating 500 megawatts of electricity for up to eight hours. That's enough to power 130,000 typical homes.