EASY ENOUGH:

When it flipped the switch on a new hydropower plant last fall, Burlington, Vermont, became the first city in the U.S. to run on 100% renewable electricity.

"It's been a long time coming," says Ken Nolan, manager of power resources for Burlington Electric Department. "Actually, the first inclination goes back to the early 1980s." At that time, the city retired a coal-burning plant, and decided to replace it with a biomass plant that runs on scrap wood from across the state.

A decade ago, the city was at a crossroads, trying to decide whether to invest long term in natural gas and other traditional power sources--or try to go fully renewable. "That was the first time we had an inkling that this might be the right thing to do," Nolan says. "By 2008, we actually saw a path where we could make this work."

Now the city runs on a mix of biomass, wind, solar, hydro, a little bit of landfill gas, and a few other renewable sources. At a given time, if the renewable plants aren't producing enough power, the utility might buy traditional power. But they also produce and sell enough extra green power that, over the course of a year, the total is 100% renewable.

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