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Testing willow as biomass

In 2008, Middlebury College finished construction on a $12 million biomass plant located near the center of campus. The project cut the College’s consumption of heating oil in half—by roughly 1 million gallons per year. The biomass plant is an integral part of Middlebury’s plan to become carbon neutral by 2016.

One of the major issues in building a biomass plant is maintaining a reasonably local, reliable, economical, and sustainable source of fuel for the boiler. Middlebury’s new boiler is designed to gasify any type of wood fuel source, but even with this versatility, finding roughly 20,000 tons of wood chips each year is no easy task. And with several other biomass projects planned around Vermont, pricing and supply issues could arise in the future if the college continues to rely solely on outside sources for wood chips.

The uncertainty over wood chip supply, among other issues, has led Middlebury into an agreement with the State University of New York College of Environmental Science and Forestry (SUNY-ESF) to develop a willow test plot on college land. The SUNY-ESF scientists, who have extensive experience studying and promoting willow as a source of biomass fuel, wanted a study plot in Vermont that would let them test willow varieties and cultivation methods in a different setting. In return, they are giving Middlebury technical advice and practical help with implementing the project.

The test plantings at Middlebury are divided between two fields just west of the campus on Route 125. The project is jointly managed by College Forester Steve Weber and SUNY EFS researchers under the direction of Dr. Timothy Volk. The Middlebury planted willows consist of five varieties and were field planted by machine to represent a mass planting. Several other varieties were hand planted in a grid to allow for more controlled study. Researchers are doing soil and water tests in the hand-planted plots and are applying measured amounts of compost, cow manure and fertilizers to test the results against a control plot. All of this research will help Middlebury decide on the varieties of willow to be planted in the future.

Depending on the success of the willow tests, Middlebury will decide whether to begin a long-term project, do additional testing, or abandon willow biomass as an option.