US college turns to anaerobic digestion to reduce carbon footprint

A college in Vermont, US, is aiming to reduce its carbon footprint by producing renewable natural gas from food waste and manure.

Middlebury College has entered into a partnership with Goodrich Family Farm in Salisbury, Vermont, Vanguard Renewables of Wellesley, Massachusetts and Vermont Gas.

The new agreement will see Vanguard Renewables construct, own and operate a facility at Goodrich Family Farm which combines cow manure and food waste to produce renewable natural gas. Gas produced in the anaerobic digester will be transported by a four mile pipeline to Middlebury College’s main power plant. The college has agreed to buy most of the new facility’s output.

“We are constantly looking at new ways to make our energy sources more sustainable and diverse, and the digester project is a great opportunity to do that,” said David Provost, executive vice president for finance and administration at Middlebury College.

“In 2016, the College reached its goal of carbon neutrality. We want to maintain that goal and keep improving on it. The digester will enable us to further decrease our use of carbon-based fuels.”


Added benefits

As well as producing renewable energy, the facility will create liquid fertiliser to reduce the farm’s reliance on chemical fertiliser. Additional benefits for the farm include lower energy costs, free heat for farm use, fewer greenhouse gas emissions, and an annual lease payment for hosting the anaerobic digester facility.

“The digester offers help with many of the challenges we face as farmers,” said Chase Goodrich, who is among the fourth generation of his family to operate the farm.

“We want to diversify our income sources and find new ways to be environmentally friendly. Here in the Champlain Valley, we’re particularly aware of efforts to reduce phosphorus runoff into Lake Champlain.” 

Currently in the permitting phase, when completed the anaerobic digester facility will produce the largest amount of renewable natural gas of any facility in Vermont. It will process 100 US tons of manure from the farm and 165 tons of organic food waste per day. According to a statement, Vanguard plans to source the organic food waste from local and Vermont-based food manufacturers including Cabot Creamery. 

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