Old coal mines could be answer to clean energy's limitations

Washington

BEN Chafin sees the future of clean energy in abandoned coal shafts.

The Virginia state senator, whose Appalachian district is pockmarked with empty mines, pushed through legislation in April that encourages companies to transform those tunnels into giant storage devices to hold vast amounts of renewable power.

The idea, which Dominion Energy Inc has been studying, is to fill mines with water and then use electricity from wind and solar farms to pump it up to a reservoir on the surface. When utilities need power, operators open floodgates, letting water gush into turbines on its way down.

"Vo…