The World’s Most Beautiful Battery

Published onOctober 3, 2018

High in the Austrian Alps, a utility has adapted a 70-year-old facility to store solar and wind energy for when it’s needed most.

The man who keeps the electrons flowing inside one of Austria’s oldest power plants is actually often caught off guard when its turbines thrum to life with the thumping baritone of a giant washing machine. The Kaprun hydroelectric station may be 70 years old, but Helmut Biberger’s job is to ensure it can handle the rapid swings in modern electricity markets. He’s helped rig the facility to generate power at a moment’s notice, using a network of winding tunnels and reservoirs built into the side of the country’s tallest mountains. The station functions as a giant battery, by using energy when it’s abundant–and cheap–to pump water to a mountaintop reservoir. There it sits in the bluest of blue Alpine lakes until power demand spikes. At that moment traders 250 miles away in Vienna open the dam, spilling that same water downhill to spin those turbines, and selling the resulting electricity at higher prices.