When I was a kid on the farm, tiptoeing through a barnyard was a way of life. It was something like playing hopscotch with cow pies. When spring came, it was time to clean out the barn, transfer the winter’s supply of manure, one pitchfork at a time, into a “honey wagon” and take it to the fields to be used as fertilizer. It amazed me how much there was, and until I researched this project, I had no idea how much manure and gasses cattle produce each day, or the effect they have on the environment. No, this isn’t fart science.

Cow manure has been discovered as an energy source: it has power and it’s being used to make electricity and ethanol. Take for example the E3 BioFuels Genesis plant in Mead, Nebraska. The $80 million facility began operation this summer, turning out some 25 million gallons of ethanol a year (a rather small amount, compared to other ethanol plants around the country). What makes this facility unique is it’s patented closed-loop system, the first of its kind in America, and quite possibly in the world.

The plant is old news, really, but here’s how it works. A nearby beef cattle feedlot provides 150,000 pounds of manure every day, which is processed through an anaerobic digester, and that produces methane. The methane is used to fire the plant’s boilers, replacing expensive natural gas, resulting in a large reduction in operating expenses. Company officials say the Genesis plant produces 46 units of energy for every unit of fossil fuel energy required, a 46:1 efficiency ratio. Conventional ethanol plants are rated at a ratio of 3:1.

A byproduct of ethanol production, wet distiller’s grain, is fed to the cattle in the feedlot and the process begins all over again. Now this is a very brief explanation of what’s happening at the Genesis plant. Their website explains it very well..

So why am I writing about this? Well, there’s more to cow manure, as you probably know. Millions of tons are produced every day by the estimated 1.5 billion cattle populating our planet. Let’s put this into some sort of perspective. The University of Wisconsin at Green Bay estimates the average dairy cow drops 148 pounds of manure each day. Do the math: that’s a lot of BS! And you thought it was all in Washington!

Dairy Farms

Haubenschild FarmSeveral dairy farms in America use the output of their cattle in much the same way as the Nebraska plant, with one exception. The Haubenschild Dairy Farm in Princeton, Minnesota, is a shining example. Instead of using the methane to create heat for boilers, it’s used to run generators that provide electric power for the operation, and supply electricity to surrounding homes as well. Anaerobic digester systems are expensive though, ranging from $200,000 to $1,000,000 depending on the size of the herd, so farmers with smaller herds have been reluctant to make that kind of investment. The USDA has free software for download that will determine digester size and cost based on the size of a farm’s herd. I found it fun, and very informative.

Hopefully, as the science of digesters improves, the process will become less costly, and more farmers and commercial operations will be able to take advantage of poop power. I was surprised to learn from The AgSTAR Program website that several pig farms are using digesters, and there’s even a duck farm in Wisconsin using a digester.

Belching

Here’s the capper: while manure provides greenhouse gasses, a cow’s breath introduces far more methane and other gasses into the air. According to the Intergovernmental Panel on Climate Change, the six million tons of methane burped by cattle in the US each year is equivalent to 36 million tons of carbon dioxide. If you add the output of sheep, goats and other ruminants, they all account for more than 18% of the greenhouse gasses that cause global warming, and that, according to the IPCC, is more than cars, planes and all other forms of transportation.

So, is the world’s cattle population contributing to global warming? It would seem so with all the belching and pooping, and the IPCC makes a strong case.

While we’re beginning to discover applications for animal manure, what about the burping? I doubt gas masks would work well on cows, and there’s no way we’ll be decreasing herd sizes anytime soon. Diet seems the best way to reduce production of greenhouse gasses produced by livestock, along with more efficient and productive methods of dealing with manure.

I’m so proud of myself; I didn’t once say “shit."