Deputy Director – Green Communities Division Department of Energy Resources
The clean energy future looks (and sounds) like this: red barns atop a hillside rippling with ripening corn, workers in dusty boots and jeans, and the bellow of a black and white cow headed for the milking shed.
It’s the cow – a Holstein –that’s key to this equation. She and about 350 others, housed in barns brimming with silage, formed the backdrop this summer as operators of an anaerobic digester at Jordan Dairy Farms told a group of public officials not only how the alternative energy technology generates electricity, but how it is literally saving the farm.
“Dairy Farming is a tough business. Our whole reason for being is so this farm can go to the next generation,” said Bill Jorgenson of AGreen Energy, LLC, a five-farm partnership that developed and operates the Jordan Farms digester. The Jordans, Jorgenson notes, have been dairy farmers for five generations – three at their current location.
A 500,000-gallon digester and other components of the anaerobic digestion (AD) system installed last year take center stage at the third generation Rutland farm these days. As visitors for Jorgenson’s tour arrived, an 8,000-gallon truck pumped food processing residuals (or source separated organics) from Agrimark in East Springfield through tubing that can deliver it to either a 10,000-gallon underground storage tank or directly to a 50,000-gallon mixing tank. Each day, up to four truckloads like this (about 45 tons) from Agrimark and six other food processing partners arrive here, and get mixed with the digester’s daily 25-ton dose of cow manure. Naturally-occurring organisms that thrive in the digester’s oxygen-free environment transform the mixture into methane-rich biogas. This, in turn, powers a 300 kilowatt (kW) combined heat and power system – producing grid-free electricity and heat for the farm, as well as nutrient-rich fertilizer as a valuable by-product.
Other economic benefits include net metering credits of 13 cents per kW hour earned by selling excess electricity back to the grid. In addition, Jordan Farms no longer needs to buy chemical fertilizer for its 1,000 acres of hay and corn – relying instead on the AD-produced organic fertilizer, which helped to double the farm’s hay yield this year.
Combined with the source-separated organics, the manure of one cow can fuel generation of the electricity needed to power an average Massachusetts home annually – and Jordan Farms has 500 cows total. Meanwhile, AD has solved significant odor and environmental problems that existed when manure was left to decompose in an open lagoon where it off-gassed methane, a greenhouse gas at least 15 times more potent than carbon dioxide. Odor is no longer an issue, and methane is sequestered through AD, shrinking Jordan’s carbon footprint (Jorgenson says removing one cow’s methane from the atmosphere is equal to cutting the annual greenhouse gas emissions of three cars).
As digester Operations Manager Shannon Carroll monitors and tweaks the AD process from her iPhone, Jorgenson maps next steps. Permits for two of the four other planned farm-based AD systems are in hand, and plans are in place for a new engine to boost Jordan Farms’ generating capacity to 450 – 600 kW with the right mix of organic ingredients. The farm hopes to soon increase its daily complement of food processing residuals to 60 tons, and is actively seeking new organic feedstocks such as municipal grass clippings.
“The whole idea of having a digester is taking waste and turning it into something else we use for power or growing crops, while helping the environment,” he says. “We want the organics everybody else wants to get rid of.”