By Sophia McDermott-Hughes/VTDigger
The largest anaerobic digester in the Northeast began full-scale production of renewable natural gas on Wednesday on the Goodrich Family Farm in Salisbury, just south of Middlebury.
The digester is an important step in reducing the state’s dependence on fossil fuels and in reducing greenhouse gas emissions in the agricultural industry, which currently produces more than 10% of the state’s emissions, according to Vermont Secretary of Agriculture Anson Tebbetts.
The two 925,000-gallon digesters, each the size of about 80 tank trailers, will convert 180 tons of food waste and 100 tons of dairy manure every day to produce enough renewable natural gas to heat 5,000 homes. More than half of the gas produced will go to heat and cool Middlebury College through a newly constructed Vermont Gas pipeline, and the rest will go to local Vermont Gas customers.
“Our farms are more than a scenic land- scape,” said Neale Lundervillle, president and CEO of Vermont Gas. “These are working lands. They are a central part of our economy, and starting today, they will play a critical role in Vermont’s clean energy future.”
Vanguard Renewables built, owns and will now operate the digester on land leased from the Goodrich Family Farm, a third-generation family-owned dairy farm and member of the Agrimark dairy cooperative. The digester will process manure from the Goodrich family’s 900 cows as well as food waste from Vermont businesses, including Cabot Creamery and Ben & Jerry’s Ice Cream.
“We’ve got a Vermont farm, a Vermont utility, a Vermont college and national energy innovators all coming together to build a model for our region,” Gov. Phil Scott said at the official startup celebration event held Wednesday at the farm, marking the beginning of full-scale production.
Middlebury College has signed a 20-year contract beginning this fall to buy 55% of the natural gas produced, which will meet 1/3 of the college’s heating and cooling needs. The college’s own biomass gasification plant will supply most of the remaining 2/3, according to David Provost, Middlebury College executive vice president for finance and administration and treasurer.
This partnership is part of Energy 2028, the college plan to transition fully to renewable energy by 2028. As part of the initiative, the college will also reduce its total energy con- sumption, divest its endowment from fossil fuels and increase educational opportunities in the environmental field.
The digester’s byproducts will find uses on the Goodrich Family Farm. The solid waste separated at the beginning of the digester’s process will be used as bedding for the dairy cows, and the “digestate” — what remains once the natural gas has been extracted — will fertilize the farm’s corn and hay fields.
The digester’s phosphorus removal system will extract phosphorus from the digestate before it is converted into fertilizer, and so reduce the impact on the Otter Creek watershed, which feeds into Lake Champlain.
High levels of phosphorus in the waterways can feed algae blooms like the current cyanobacteria bloom in Lake Champlain and lead to eutrophication, as the decomposition of the algae consumes all the oxygen in a body of water, choking all other marine life.
The excess phosphorus will be sold to farms in other areas of the state where the soil lacks the nutrient and where it won’t cause runoff problems.
The digester project began in 2009, after Goodrich Family Farm and the rest of the Vermont dairy industry took a huge financial hit during the 2008 financial crisis. Needing to diversify the farm’s income stream, the family approached Middlebury College with a proposal for an anaerobic digester.
The project progressed in fits and starts until 2017, when Vanguard Renewables joined the project, according to Chase Goodrich, one of the farm’s co-owners.
“We just saw [the digester] as a neces- sity,” Goodrich said. “We knew that this was the direction we needed to head in to make a real change.”
Vanguard Renewables completed construction on the digester in June, after the pandemic caused delays in construction and shipping of the necessary equipment.
“Waste is a mindset,” said John Hanselman, the founder and chief executive of Vanguard Renewables. “Here in Vermont, we’re setting a precedent and example that we think is going to be replicated over and over again across the U.S.”
Goodrich Family Farm was in the news earlier this year, when Migrant Justice — a farmworker advocacy organization in Vermont — accused the business of mistreating and withholding pay from one of its workers, and a protest followed.
“It was definitely unfortunate, and I don’t think we handled ourselves well,” Goodrich said. “The only thing I can say is that that really does not speak to who we are. We care about our animals. We care about our people. We are family-first.”
Goodrich says they have since settled everything with the worker and he deeply regrets the incident.
“We did do due diligence and we worked with the farmers and with Vanguard to ensure that all employees working at the firm are treated appropriately,” said Provost. “We did not find evidence to support ending a relationship.”