Willow project continues to thrive

Since its inception in 2007, the Middlebury willow project has been running according to plan.  The first harvest and testing of willow trees as a sustainable fuel source for the biomass gasification plant will happen this coming December.

The biomass gasification plant, which uses wood chips as fuel, currently runs on waste product from local sawmills.  Assistant Treasurer and Director of Business Services Tom Corbin is a leader of the project and has been working with several others to find alternate sources of fuel for the plant.

“In the winter there is more competition [for fuel] from the local K-12 schools,” said Corbin.  In order to find an alternative source of fuel, Corbin has been working closely with the State University of New York’s College of Environmental Science and Forestry (SUNY-ESF) which is using the College as a testing site.

“We looked at two or three varieties of short-rotation crop trees,” said Corbin.  They decided on willow trees and, in 2007, a nine-acre plot of trees was planted to test their potential as a fuel source.

Dr. Tim Volk, professor and research associate with SUNY-ESF, is the leader of the scientific studies of the willows.  He and his team were involved in the planting in 2007 and have been closely monitoring the project since then.

“We are interested in seeing which varieties will do best in the soil conditions in Vermont,” said Volk.

“[The College’s] concern is what will happen in the winter,” said Corbin.  “It’s been a good partnership for us. They know what they’re doing to help the plants … it’s like free consulting.”

According to Corbin, one of the advantages to growing willows in that the process is quite simple.  The trees are trimmed one year after the original planting to aid in multiplication.  After that, they grow for three years and are ready to be harvested. The trees are cut down and shredded with a slightly adapted corn-harvesting machine and are ready for use in one simple step.

“There’s no processing necessary,” said Corbin.  If all goes will with this nine-acre test, Middlebury plans to expand the project to a 1,500 acre plot that will provide 500 acres of trees each year, enough to supply about half of the fuel needed for the winter.

Besides saving money for the College, the willow project has many other benefits.

“It will be good economically for the county,” said Corbin. “We employed many local farmers to help with the planting and we hope to employ more for the harvesting in December.”

In addition, the use of locally grown willows for fuel is a much more sustainable and environmentally sound practice.

“It’s a simple, organic process,” said Corbin. “We started with organic cow manure, applied biodegradable herbicide during the first year, and we have not used any chemicals since then . . . We are not taking wood from the forests, we know where it’s coming from — it’s only trucked a few miles.”

The primary goal of this test was to see how the willows would do in this “different ecosystem and different weather patterns,” said Corbin.  Both Corbin and Volk said that the trees are doing “as well or better” than has been seen in previous tests in central New York and elsewhere.

Some lessons have been learned that could be applied in the future.  Among the many varieties of willows, “some have grown extremely well and some have done poorly,” said Volk.  “Because of the high clay content of the soil, the trees were slow getting started,” said Volk.

“We should have spent more time getting the ground ready to plant,” said Corbin. “Weeds were also a problem at the beginning.  More preparation would allow us to reduce the amount of chemicals we use.”

Predictions for the upcoming testing are positive, but there are some uncertainties. According to Corbin, this is the first time willow will be used in such a plant.

“There may be a less consistent chip size,” said Corbin. “The wood is not as dense so we may find that instead of needing 10,000 tons, we need 13,000 and we need to plant more.”

“The willow wood chips are not much different from the ones they use now,” said Volk. “This harvest should provide enough to do a test for a couple of days and play with the dynamics.”

The biomass gasification plant will require three to four days worth of fuel to do a decisive test, according to Corbin.  In order to keep the plant running at full temperature, a mixture of willow and the existing fuel will be run through the plant before the transition to pure willow is made.  After the pure willow has been tested, a mixture will be used again to transition back to the original type of fuel.

“There are some pockets that did not grow as well,” said Volk, who is not sure there will be enough yield to do the full test.  “However, we have backup supplies of willow ­­— truckloads that we can bring in to make sure the test can be done.”

“The proof is in the test,” said Volk.