In the German state of North Rhine-Westphalia, a coal mine will close in 2018. Aging coal infrastructure, low wholesale power prices, and a move away from the highly polluting power source all make renewable energy the political darling of the day.
But that doesn’t mean the Prosper-Haniel coal mine will be shutting down completely. According to Bloomberg, North Rhine-Westphalia State Governor Hannelore Kraft recently confirmed that a project to turn the coal mine into pumped storage will move forward after mining activities have stopped.
Pumped storage has been used for decades, but placing a pumped storage scheme at a retired mine is somewhat new. Here’s how it works: when electricity is plentiful and cheap—say, on a windy day when the Sun is shining and solar panels and wind turbines are working at their maximum—a pumped storage facility pumps water from a lower reservoir up to an upper reservoir. When electricity is scarce, the facility can release the water back down to the lower reservoir through a turbine, creating renewable hydroelectric power.