Big Power Goes Local

by Dave

In the late 1990s, the town of Freiamt in Germany’s Black Forest decided to take the fight against global warming into its own hands. Three hundred of the town’s 4,300 residents chipped in to buy the four 80-meter-tall Enercon wind turbines that now top the surrounding hills, generating 1.8 megawatts each. An additional 270 families put solar collectors on their roofs to heat water and power their homes. Three businesses—two sawmills and a bakery—whose land abuts a gurgling stream have installed old-fashioned water wheels, each providing an additional 15 kilowatts.

To make up for shortfalls when the sun doesn’t shine or the wind doesn’t blow, one of the local farmers invested in a “biogas” fermenter, which uses enzymes to turn grain and agricultural waste such as manure and chaff into methane. The gas, in turn, fires up an electricity generator. And rather than simply release heat given off in the process into the air, as conventional power plants do, the generator pumps the waste heat into nearby homes, where it’s used for water and space heating, through pipes laid by volunteers. But the prize for Freiamt’s most creative source of energy surely goes to Walter Schneider, a local dairy farmer. To harness the energy set free when the milk from his 50 cows is chilled before transport, Schneider installed a heat exchanger that uses the heat from the cow’s milk to warm the water he needs for cleaning and showering. Today, the Freiamters are proudly self-sufficient. What’s more, in 2007 they generated an extra 2.3 million kilowatt-hours beyond the 12 million they consumed. They sold the surplus, enough for an additional 200 homes, back to the national grid.