A family-owned and operated dairy farm in Berkshire County, Pine Island Farm spans 1,300 acres of cropland, houses approximately 1,000 head of Holstein cattle, and produces and sells 12 million pounds of milk from 750 cows annually. A fully-grown milking cow can produce upwards of 100 pounds of manure per day, which can create odors and - due to carbon dioxide and methane produced during decomposition - greenhouse gas emissions. Prior to 2011, manure at the farm was stored in a 4.1-million-gallon slurry tank and spread on cropland as fertilizer. That changed in November 2011, when Pine Island Farm began using the manure as feedstock for its new anaerobic digester with a combined heat and power (CHP) energy system. Today, the digester takes in mostly manure; up to 8-10 percent of the feedstock is excess whey from a regional dairy processor. With electrical generation capacity of 225 kilowatts, the farm's organics-to-energy conversion system generated more than 1.1 million kilowatt hours (kWh) of renewable electricity in its first eight months of operation. The energy produced covers all of the farm's electricity use, helps heat its water, and runs the digester equipment, while still enabling the farm to sell power back to the grid. For Pine Island Farm, anaerobic digestion technology has multiple benefits: it enables a more sustainable practice for manure management that also generates renewable power, cuts greenhouse gas emissions, reduces the need for petroleum-based fertilizers, helps protect groundwater from manure leakage, and is estimated to reduce odors by about 75 percent. Moreover, Pine Island Farm can now contribute energy to the New England electric grid, helping to diversify Massachusetts' energy supply through domestic renewable resources.
In business since 1941, Jordan Dairy Farms is a fifth-generation, family-owned and -operated farm with 300 milking cows. In 2010, Jordan Dairy joined four other Massachusetts farms to form AGreen Energy , LLC, a partnership designed to enable the farms' transition to more sustainable manure management practices. All five farms plan to adopt anaerobic digestion technology with combined heat and power (CHP) conversion units to transform manure into renewable energy. Jordan Dairy, the first of the five farms to build an anaerobic digester, also partnered with Casella Resource Solutions to bring in source-separated organics from several local food companies (including HP Hood & Sons, Cabot Creamery, Kayem Foods, and Cains Foods) to convert their food waste to energy instead of sending it to landfills. The Jordan facility takes in 9,125 wet tons of manure and 16,425 tons of source-separated organics per year. The system has a capacity of 300 kilowatts and is estimated to generate 2.24 million kWh of electricity per year, enough to power the farm and 300 homes. Thus, with the added organics, one cow at Jordan Dairy Farms produces slightly more electricity than is needed to power one average home. The digestion system works so well that Jordan Dairy is considering increasing the engine size.
As a sustainable waste management option, anaerobic digestion improves air and water quality, mitigates odors, and reduces farm greenhouse gas emissions. In addition, Jordan Farms uses the solids from the digestate for animal bedding and the liquid as a valuable fertilizer, lowering costs further and increasing overall crop yields. The anaerobic digestion projects at the five AGreen Energy farms will diversify their operations, providing farm owners with additional revenue and helping to keep small-to medium-sized farms in business. When fully operational, the anaerobic digesters at all five farms could collectively handle up to 15 percent of Massachusetts' source-separated organics, using it to generate local, renewable energy.