Burlington, Vermont, has been making waves for becoming the first city in the U.S. to be powered 100 percent by renewables. (Some may say Greenburg, Kansas was the first, but we are talking about a town of 800 people versus 42,000 in Burlington.) Reliant on coal a generation ago, Vermont’s largest city has slowly revamped its energy portfolio, culminating in the purchase of a hydropower plant late last year.

This milestone may not be surprising considering Vermont’s progressive politics and buy-in from residents who overall supported the plan of the local utility, Burlington Electric. But the fact that Burlington has been able to do this without raising rates since 2009 -- while saving the city about $20 million over the next 20 years -- creates a case study for communities that are interested in investing in renewables but skittish about making such an aggressive move.

Granted, Vermont’s local topography has helped Burlington achieve its goal. Before “biomass” became a commonly used word, the city had invested in a power station that for 30 years has been fueled mostly by wood chips. Most of the fuel stock used at the McNeil Generating Station comes within 60 miles of its location, with the resulting biofuels derived from logging residue and culled tree material. An adjacent scrap yard accepts more waste wood from residents who are willing to drop it off. As a result, the power station, which can consume 76 tons of wood chips an hour, can generate up to 50 megawatts (MW) of electricity — long providing a third of the city’s power needs.

About 20 percent of the city’s electricity comes from wind power, most of it from a nearby 40 MW project that has operated for four years. A smaller portion comes from solar energy the city purchases, including a solar array at the local airport that flipped the on switch late last year.

The largest share of electricity comes from hydropower — much of it is purchased from plants running in Maine, in addition to the city’s latest purchase, a plant on the Winooski River. Other programs, such as a smart grid project, have helped the city use energy more efficiently: In fact, Burlington uses less energy now than it did in 1989.

Not everyone is impressed with Burlington’s renewable portfolio. Interviewed in a PBS news segment, Sandra Levine, an environmental attorney, alleges Burlington Electric is using creative accounting to show they city is running on 100 percent clean energy — and particularly takes issue with Burlington relying in part on an old Maine hydropower plant. But in fairness, Burlington has done something no community in the U.S. has done before: revamp its energy portfolio while keeping electricity cost-competitive for its residents.

Image credit: Burlington Electric

Based in California, Leon Kaye has also been featured in The Guardian, Clean Technica, Sustainable Brands, Earth911, Inhabitat, Architect Magazine and Wired.com. He shares his thoughts on his own site, GreenGoPost.com. Follow him on Twitter and Instagram.