“Energy Shift Creates Opening For ‘World’s Largest Batteries'”

“LUDINGTON, Mich. — Sprawled like a gigantic swimming pool atop a bluff overlooking Lake Michigan is an asphalt-and-clay pond holding enough water to produce electricity for 1.6 million households.
It’s part of the Ludington Pumped Storage Plant, which uses simple technology: Water is piped from a lower reservoir — the lake, in this case — to an upper one, then released downhill through supersized turbines.
Supporters call these systems ‘the world’s largest batteries’ because they hold vast amounts of potential energy for use when needed for the power grid.