Ice Cream Helps Dairy Farm Put Energy on the Grid

It’s not exactly like the ice cream man visits twice a week at Bill Rowell’s dairy farm in Vermont.

Yes, a truck from the iconic Ben & Jerry’s company heads to his Green Mountain Dairy, but it isn’t bringing a cool treat for Rowell, who runs the farm with his brother Brian.

Instead, the truck is carrying wastewater – about 6,000 gallons weekly – that comes from the nearby ice cream manufacturing plant. The waste finds a second life in the farm’s methane digester that the Rowells installed 12 years ago to manage the cow manure produced by their 950 cows.

Experts helped determine that the ice cream-infused wastewater could be included in the digester along with other organic matter to produce energy. The farm struck a deal with the company to accept water that flushes the plant’s ice cream lines every time it has a flavor change.

Bill Rowell

Rowell said it’s a win-win partnership and something visitors to his farm get a kick out of.

“When you tell people you’re using Ben & Jerry’s ice cream as feedstuffs for your digester, they say, ‘Whaaaattt? Why do they do that?’” Rowell said. “Then you explain how it reduces their costs to operate and it’s producing something useful. Then the consumer says, ‘Hey that’s pretty cool.’”

Green Mountain Dairy's methane digester

Methane digesters are one way that U.S. dairy farmers are committed to sustainable farm practices. Digesters come in different sizes and styles, but the concept involves a closed tank where manure and other organic matter is collected in an oxygen-free environment. Micro-organisms break down the materials in a process called anaerobic digestion, creating biogas that can be used to produce electricity.

Farmers and others in the dairy community are passionate about creating renewable energy options. Whether installing methane digesters like the one at Green Mountain Dairy for effective recycling or using solar and/or wind to help power farms, the dairy community is evolving to be more sustainable every day.

A generator that helps the dairy's methane digester create renewable energy

Rowell said his dairy exports about 1.8 million kilowatts of power to the grid each year, enough to power about 400 average-sized homes.

Billie Davis, environmental specialist for Ben & Jerry’s, said the relationship fits nicely into the company’s goals of producing ice cream in a way that has a minimal impact on the environment. She said the company also has worked with other dairies in the region that have digesters.

“From day one, Bill really liked the idea that his farm produces high-quality milk that is coming back to our facility that we’re using to make products and then the waste product is going right back to his farm,” she said. “So, it’s kind of a closed-loop system.

“This is business as usual for us. This helps us and our commitment to reducing our environmental impact from our manufacturing process,” Davis said “We set targets every year to reduce waste. Of course, we don’t want to create any waste, so we’re always looking to reduce waste and we want to manage it in the most sustainable way possible.”