Think an anaerobic digester is financially out of reach for your small- or mid-size dairy? Perhaps not.
Nina Ksherty, head of the renewable energy division for the environmental services firm TWS Group Inc., presented “Affordable Dairy Manure Digesters” at the New York Farm Show Feb. 21-23 to help farmers learn how, even on smaller farms, digesters can both save them money and create a new revenue stream.
The improved design of digesters by TWS has lowered the cost. Ksherty said that by building a less customized, smaller-size digester, many smaller farms will be able to afford installing them.
Digesters have increased in popularity among dairymen and in various other ag sectors because they help manage waste, reduce the need for bedding, power farms and, in some cases, generate salable energy.
But installing digesters in the Empire State has become particularly popular because of the yogurt boom.
“One of the benefits of the digester is its ability to treat the waste and dairy whey,” Ksherty said. “There’s been a push by the government to promote digesters to process waste and the byproduct of the yogurt industry. The more general trend is digesters for organic food diversion programs. They’re setting a goal that a certain percentage of organic waste should be sent to digesters and not landfills.”
New York farmers with digesters near yogurt plants and other food processing facilities are getting paid to take food byproducts, unlike other areas where there’s not as much byproduct available.
In addition to the extra revenue, the farmers receive other benefits.
“The whey increases the power output of their digester,” Ksherty said. “They have a high biogas production value compared to manure. For the same volume of digester base, they generate more gas.”
Affordability has been a major obstacle for small farms installing digesters. Typically, they’ve only been economical on farms of more than 1,000 head, and even those rely heavily on federal and state grant funds. In New York, the majority of dairies are fewer than 500 head in size, and many of those are fewer than 100 head.
TWS has been developing standardized designs that, along with federal and state grants, can make it possible for these smaller farms to afford their own digester. Much like buying a computer system that’s ready to go out of the box (instead of building a system from scratch), the TWS designs will be easier to install, and less customized.
The company recently implemented its first small-scale dairy farm digester at Joneslan Farm, a 220-head dairy near Hyde Park, Vt.
“That was our first installation of a digester that involved pre-fabricated components and reduced site work,” Ksherty said. “The farmer could not find someone to do the job for the price he wanted to pay until he met TWS.”
Still, the project was funded heavily through grants, including one from the Clean Energy Development Fund from the State of Vermont, and one from Natural Resources Conservation Service.
“Not every farmer will get that kind of grant,” Ksherty said.
In total, the farm received a little less than $1 million.
“From that project, we’ve improved the design and we’re working on version two of the small dairy farm digester design to bring cost down even further,” Ksherty said.
The return on investment for a small-scale digester is around 10 years, which includes savings on bedding, heat recovery and power generation. Digesting food byproducts with waste also adds nutrients to the manure.
At the Hyde Park farm, the power is connected to the grid in a bi-directional meter. Power can be sold to the grid or directed back as needed. During certain parts of the day, the farm is at peak power consumption so power may be imported, and other points of the day, it’s at low power consumption so the farm’s exporting.
Ksherty said the New York State Energy Research and Development Authority “offers a good grant. And a push by the governor to get digesters in will help those interested in a digester.
“There has been a general feeling that small farmers shouldn’t even attend a seminar like this, but there are solutions out there if we think creatively,” she said. “Farmers are some of the best people when it comes to thinking cost-effectively. It shouldn’t be that digesters are so out of reach for farmers. We want to reach out to farmers and see what their challenges are and how we can address them.”