EXETER — Adam Wintle sees too much of a good thing when he reads the electronic panel attached to the side of his $6 million anaerobic digestion system. An engine generates electricity by consuming 340 cubic feet of methane-rich biogas gas per minute. But another 200 cubic feet of gas is shooting up a pipe and burning off in a flare.
“We’ve got a lot of excess gas,” Wintle says. “That gas could be running another engine.”
The digester is essentially two enormous crockpots that cook a stew of cow manure and food waste at 100 degrees. Built just over three years ago, it is the largest anaerobic digester in Maine and among the largest in the United States. It produces enough electricity to power all the homes in a town the size of Boothbay Harbor.
The 1,000 milking cows at the adjacent Stonyvale Farm supply the manure. Hospitals, restaurants and grocery stores provide the discarded food.
Wintle, 34, his brother, John, 37, and sister, Sarah, 35, are ambitious, and they enjoy the support of their major investor, Stonyvale Farm, the second-largest dairy farm in the state.