Farmers can profit from their cows, pigs and chickens in more ways than one. Along with producing milk, eggs and meat, the animals make manure, and a lot of it. Farms can extract methane from livestock waste through a process called anaerobic digestion. Across the country, 162 farms generated about 453,000 megawatt-hours of electricity last year.
I discussed one of those farms recently. On 9,000-hog farm in North Carolina, Google is offsetting some of its carbon emissions by supporting a pig power project. Questions arose in the comment section on whether anaerobic digestion would be profitable without such financial backing mechanisms, and if so, why weren’t more farms getting into the poop power business.
According to a new study, published in the Journal of Dairy Science, manure-to-methane systems can bring in the moolah. But yes, farmers do need a helping hand—in the form of grants, government subsidies, or customer support—to get their systems up and running. Upfront equipment costs, after all, can fall between $1 million and $3 million.
Studying six dairy farms over seven years, the researchers from the University of Vermont found that base electricity price and premium rates strongly influence the farms’ profitability. Customers of the Central Vermont Public Service volunteered to pay $0.04 more per kilowatt-hour for the cow power.
To those customers, paying a little extra is worth it. According to the Environmental Protection Agency, U.S. anaerobic digesters cut methane emissions by 51,000 metric tons of methane (equivalent to 1.1 million tons of carbon dioxide). This methane power also replaced about 264,000 tons of CO2 emissions from fossil fuels.
The study found the selling of byproducts from the digesters also plays a huge role in the barns' bottom lines. For instance, 26 percent of the dairy farms’ 2008 revenues came from sales of compost and animal bedding. Additional benefits come from recovered heat. To help farmers grow more vegetables over in Massachusetts, AGreen Energy (AGE), a company that installs anaerobic digesters, hopes to build greenhouses warmed by digester waste heat. AGE also trucks in food wastes so the farms can mix it in with their manure.
All in all, the study found a team effort is necessary for successfully reaping the most bucks from the herd. Lead author Qingbin Wang says in a statement:
For any community interested in a locally sourced renewable energy project like the CVPS Cow Power Program, the strong commitment and collaboration of utilities, dairy farmers, electric customers, and government agencies at the state and local level is essential.
Related on SmartPlanet:
- Google takes stink out of pig waste
- Human waste now heats British homes
- California laws becoming ‘dairy digester’ intolerant
- Energy happens: NYC seeks sewage power