WASHINGTON, Feb. 23, 2016 -- Turning livestock manure into biogas isn’t just for generating electricity any more.

Patrick Serfass, executive director of the American Biogas Council (ABC), tells Agri-Pulse that biogas makes it possible “to simultaneously manage organic waste materials” while creating 24/7 baseload renewable electric power, transportation fuels, and a nutrient recycling process.

Low oil and natural gas prices are challenging biogas systems designed to generate electricity, putting some out of business (at least until oil and natural gas prices head back up again). Serfass says members of his trade group are responding by developing multiple markets.

“If you’re in a state like Wisconsin, where the utilities are very unfavorable to renewable energy generation right now,” he explains, “it’s very difficult to make a new and simple biogas system pencil out when the utilities only pay you 3 cents a kilowatt hour for your electricity.” For example, an anaerobic digester system for a 750-cow dairy can cost over $1.5 million to build.

The good news, Serfass says, is that a biogas system generates “lots of different products because you are producing a gas, liquids, and solids and there are products that you can create from each one of those outputs as well as combinations of them.”

Take fertilizer, for example, he says. “It’s crazy to import ag nutrients” when the U.S. is overflowing with nutrient-laden organic wastes, “whether it is manure or food wastes or biosolids in wastewater.”

When electricity prices are low or utilities have no interest in buying renewable power, Serfass says that thanks to 2014’s improvements to the federal Renewable Fuel Standard (RFS), some biogas facilities are using the gas for transportation fuel. They are also turning their liquid and solid anaerobic digester “digestate” into high-value custom-tailored soil amendments and fertilizers to replace fossil-derived and synthetic fertilizers. The result is “a super fertilizer, pre-digested, almost pathogen free, ready for plants to absorb the nutrients immediately” along with the fiber residue turned into “great bedding for livestock” or compost.

USDA made the same pitch for diversification in its Biogas Opportunities progress report in December, concluding that:

·      “One of the first biogas systems built on a dairy farm in Wisconsin recently shut down because the original utility contract expired and the current rate had dropped, meaning the local utility will now pay less than half of the rate when the project was first built. Since Wisconsin’s Renewable Portfolio Standard (RPS) had been met, there was a reduced need for renewable energy for RPS compliance. With less than half of the revenue now available, it was no longer economically attractive for the farm to run the digester. The owners of the dairy decided to shut down their digester and to pursue other manure management practices, giving up the odor reduction and environmental benefits they had been contributing.” 

·      “In order to fully finance biogas systems, it is often necessary to be able to market co-products in addition to the energy produced by the system. This could include focusing on separated nutrients, marketable fertilizers, or soil amendments. Local niche markets can sometimes exist for these co-products, but in order to make financing more available and attractive, developing a stable and reliable national market for these co-products would be important.”

A prime example of what can be done to serve multiple markets is Fair Oaks Dairy Farms in Indiana which includes 12 family farms with a total of 36,000 cows. When the local power company wouldn’t pay enough for biogas-generated electricity, co-founder Mike McCloskey planned to purify the gas to sell as pipeline gas. When plummeting natural gas prices ruled out that option as well, Fair Oaks instead converted to running its milk tanker trucks on its own compressed natural gas (CNG).

Fair Oaks also figured out how to recover the nitrogen and phosphorus from the biogas process, producing high-value fertilizer. This additional co-product moves the operation another step toward McCloskey’s goal of creating a zero-carbon-footprint dairy.


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