US Dairy Farms: Untapped Biogas Potential

by Peter Brown (Euro Marketing Tools, FFA Fuels Inc./Biomass Magazine) Countries like Holland and Norway have achieved success in widespread digester installation at dairy farms, but U.S. dairy states are slow to follow suit. -- Dairy farms have been operating in the Pacific Northwest since 1836. Their owners, for the most part, were Dutch and Belgian immigrants. The land was plentiful and rich, with enough grass to feed the hundreds of small dairies holding 30 to 100 cows, resulting in a robust dairy industry from Canada down through Northern California, and as far east as Idaho and Alberta.

Then things started to change—the number of farms became fewer, but they became bigger with more cows, which became too many to handle in that free and easy way that cows like to be handled. For organizational purposes, they were housed in barns where they stayed most of the day, shuffling to and from milking stations.

Periodically, accumulated manure was cleaned out of the barns and trucked out to a shallow cavity scooped out of the earth, and then allowed to decompose in the open air. The manure pile became an eye and nose sore, as it did not dry out and began leaching into the ground. In times of high rains, lagoons would overflow and dilute the contents. These were the holding ponds of a primitive system of fertilization for the silage needed to feed the animals in their stalls, and spread in the barns as bedding. In present times, these some 9 million dairy cows can produce 209 million tons of milk a year, down from 22 million cows in 1950 and reducing the carbon hoof print by a third.

In Washington, there are over 100 large dairies with greater than 500 cows and up to 15,000 cows—and this is just one dairy state that isn’t the largest. The math is simple—dairy cows produce an estimated a net daily biogas output of 40 cubic feet (1.2 m3) per cow, and Washington has 262,000 dairy cows. The state could be sitting on an estimated 104. million cubic feet of gas that is not being harvested, instead importing fracked gas for its needs.

Enter the digester, a self-contained environment where bacteria attack the manure stream in precisely controlled temperatures and rates of passage. Inside the digester is raw sewage—a toxic mix of the residue of the four cow stomachs cleaning or sluicing water, and often the grassy bedding of the cows. As the manure enters the container, it is exposed to an anaerobic environment that quickly generates bacteria that may have been injected from a menu of suitable bugs. These break down the solids into methane and CO2, digestate, and some critically useful and recoverable components like dried fertilizers high in ammonia, water purified as highly as required for cleaning, and for irrigation on the fields.

“We have many options, developed over the years, to convert waste to cash,” says Hans Camstra, a Dutch system engineer specializing in renewable energy, digesters and large recycling systems. “The easiest is to run a modern generator off the gas, remove the fertilizer and bag it, convert solids to bedding and spray the remaining digestate onto the fields.”

So how many cows are there in America? One census claims that there 87 million— good reason to bring all that methane to market, and if funding is provided, replacing oil terminals, tar sands, fracked gas and the whole fossil fuel infrastructure with the same gas, diesel, methanol, oil and other products from the modern alchemy of our biochemist.

“I am also very interested in how far a digester and gas handling system can go to add to the bottom line,” he (Matt Plowman, a dairy farmer between Yelm and Olympia, Washington) says. “I have heard some rare horror stories from California dairies where contracts last two years and suddenly income drops, or new transformers have to be added making the upgrades a total liability.”

When informed that in Holland, co-ops have become the norm, Plowman says he would discuss the possibility of creating a group with 10,000 cows to have the economy of scale that would vault his dairy into real, industrial production of methanol or coordinated food production.

As for how to pay for a system and get it built, the real play will be in how to generate long-term financing from the same place the equipment is purchased. Norway, for example, has EXIM financing that, after qualifying, can bring 85 percent of a project for around 2.5 percent for 18 years, using Norwegian technology and equipment. Rabo Bank in Holland has a massive agricultural investment in the U.S., and covered the Lost Valley Farm. The money is there; the rates and the service are based on working with dairy and other farms around the world. Each system should be built as a springboard for additional services, more offtakes and more revenue, designer bugs for direct diesel production, additional additives grown on the farm and a small biodiesel esterification unit. READ MORE