MIDDLEBURY, Vt. -
With the arrival of fall, it's prime operating season for Middlebury College's biomass gasification plant. The $12 million project, located in a see-through building at the center of campus, went online back in 2009. It provides supplemental steam for heating and electricity to the school's existing power plant, and cuts the college's fuel bill in half.
Jack Byrne, Middlebury's director of sustainability, says the concept got rolling several years ago in a classroom when students were challenged to come up with ways to reduce the college's carbon footprint. They learned the benefits didn't stop there.
"We're spending $800,000-$900,000 of new money in the local economy by buying wood chips from within 75 miles, instead of a million gallons of fuel oil from very faraway places," Byrne said.
The Middlebury project is one of dozens of small-scale biomass projects around the state in recent years; from the 43 schools that now heat with wood chips or pellets, to the city of Montpelier's efforts to create a heating district downtown.
"Pellets and wood chips have been a very price-stable fuel, and so the fuel savings between oil and propane compared to chips and pellets is large enough that if someone invests a few thousand dollars, or $10,000 or $20,000 in a system, there is a rate of return on that investment," said Adam Sherman of the Vermont Energy Investment Corporation.
Just up Route 7 in Vergennes, Armory Lane Senior Housing made the investment. The 25 apartment, low-income facility opened earlier this year. A silo outside holds up to 10 tons of wood pellets. The pellets are sucked inside by vacuum and automatically fed to a small boiler.
"The convenience of this type of setup is on par with your oil, propane and natural gas heating system," Sherman said.
Convenience, but some critics say at what cost? As this project and others like it scale up and the potential demand from larger industrial biomass users like the McNeil plant in Burlington increases, will Vermont's forests pay the price?
"Those who actually want to see more of the smaller-scale facilities, like the Middlebury facility or the district heating in Montpelier, they should be very concerned about the large scale biomass facilities such as McNeil," said Josh Schlossberg of the Energy Justice Network.
Schlossberg spends his days tracking and documenting the source of McNeil's wood supply, and he doesn't like what he sees.
"Their own numbers are that they burn 30 cords of wood an hour, which is about 400,000 green tons a year, which if you take the clear-cut equivalent-- all that wood, stacked into trees in acreage-- that would be about 3,500 acres, or 3,500 football fields of forests a year," Schlossberg said.
Under state regulations, McNeil is required to have four foresters to monitor and sustainably source the wood supply. "There's always a level beyond which wood should not be cut. And that level would be what is the net growth after mortality and other considerations of preservation and biodiversity-- that level should not be exceeded, but in Vermont there's a long way to go before we reach that level," said Bill Kropelin, McNeil's chief forester.
"This is a difficult question because that's what we need to insure, is that we have enough wood to supply the existing plants-- all the existing uses of wood, industries that use wood that do so many good things for Vermont and any new facilities that might come on line using wood. That's why efficiency matters and it's why we want to be careful how we use the resource," said Mike Snyder, the commissioner of the Vt. Forests, Parks & Recreation Department.
A legislative study due out early next year is expected to evaluate the environmental effects of biomass and other renewables.
Meanwhile, state officials say current forestry models show there is room for growth.
"Biomass is not a silver bullet," Sherman said. "It's a silver piece of buckshot. When coupled with conservation, efficiency and the full spectrum renewables, we'll be making progress."
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Industrial biomass in Vermont
