In Scotland, we use lochs as storage batteries: When there's a surplus of energy, that surplus drives hydro-pumps to pump water up-stream into dams, and when there's a deficit, the water's allowed to flow, powering the hydropower dams in the process.,(reply>), i think meny places do its just wether or not they can be filled or need to be used at the time,(reply>), Nice.,(reply>), @Acme Fixer I've seen this! It's a neat idea. I hope they are successful.,(reply>), @Paul Smyers <br>There's a company that's building a similar storage system that stacks heavy blocks up or lowers them down depending on the electric demands.,(reply>), @Brian Wyters you can have batteries kick in fast and then when hydro gets up and running it takes over