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.
Even though the utility is paying more for green energy than it would for something like coal, costs haven’t gone up for residents. Burlington uses complicated accounting to make that possible, selling renewable energy credits to utilities in places like Massachusetts, which has state laws requiring certain renewable power goals. When utilities can’t actually meet those goals, they buy certificates from a place like Vermont.
“We might sign a contract with a wind project and agree to pay them 10 cents a kilowatt hour,” Nolan explains. “We’d then sell the renewable energy credit to the utility in Massachusetts for five cents a kilowatt hour, and that effectively makes the cost of the wind power look like five cents to us.”
The city then turns around and buys cheaper renewable credits from somewhere else. It’s a somewhat messy process that some people criticize–if a utility in Massachusetts can buy credit for renewable power without actually using it, that state isn’t really making progress toward its goal. But as the price of renewables keeps going down, Burlington may not have to sell credits anymore.
“It’s a commodities market, so prices move around a lot, and there are years where the prices have been low enough, we’ve considered retiring the credit,” Nolan says. “We’re trying to balance renewability with rate stability, and every year that conversation has to happen.”
One of the reasons the city can run on renewable energy is that it has also worked hard to help residents use less power overall. With an aggressive energy efficiency program, the city actually uses less energy now than it did in 1989.
But even though Burlington has some unique circumstances–and a very liberal population that strongly supported the push to 100% renewables–Nolan believes that it’s a goal that other cities can easily reach. Some smaller communities (like Greensburg, Kansas, which rebuilt with green energy after the town was destroyed in a tornado) have already achieved the goal, though Burlington is the first larger city.
“I think the key for us was really assessing what we had for natural resources in our area and trying to take maximum advantage of those,” Nolan says. “For example, the wood plant–Vermont has a lot of forests. Figuring out how to maximize the use of that in a way that stabilized our costs was important. And small hydro plants are all over the place in the Northeast.”
“It’s a challenge for folks,” he adds. “Renewables are still more expensive than traditional coal plants or natural gas plants. But if cities really take the time to assess what they have for resources in their area, and take advantage of any financial markets that may be available, I think it’s doable.”