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Cow Power: From Manure and Intestinal Gas—Yes, Farts!

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While greenhouse gases have always existed and are essential to keeping the Earth's temperature at a level warm enough to make human life possible, the amount of greenhouse gases being emitted by human activity and industry is now threatening to give the Earth a dangerous fever.

Methane gases are major contributors to global warming. Many things create excess greenhouse gases, and the innocent cow is among the worst of culprits. That's right. The gas that passes through the intestines of cows—and out into the atmosphere—is responsible for a large percentage of problematic greenhouse gases. In beautiful New Zealand, a country with little in the way of the kind of pollution that plagues its more industrialized neighbors, more than half the country's greenhouse gases currently come from cow "emissions." So scientists from New Zealand and Australia are spending millions of dollars on a project to breed a less "gassy" cow.

But there's another way to solve this gassy problem—process the gas from cows and the gases that are produced from cow manure as fuel, fuel that can supplement gas or replace diesel fuels and can also be converted into electricity. It works like this: Bioenergy is energy generated by the decomposition of organic material, such as material that comes from plants or animals. Cow manure or manure from other livestock is an organic material. As it decays it also becomes a major source of methane gas, a dangerous greenhouse gas over twenty times more potent than carbon dioxide, when it comes to trapping heat and contributing to global warming. But if the methane gases from all that animal poop can be harnessed and utilized, not only will global warming be slowed down, but we will have a great source of renewable energy.

There are two ways that organic material decomposes. One is aerobic decomposition, which means the material decomposes in the presence of oxygen. The other is anaerobic decomposition, which means the material decomposes in the absence of oxygen. The products yielded by these two types of decomposition are very different. Aerobic decomposition produces the following: carbon dioxide; ammonia; lesser amounts of a variety of other gases; and a great deal of heat. The heat can be used for a specific purpose, or the decomposed material simply becomes fertilizer. In anaerobic decomposition, a nitrogen-rich fertilizer is a by-product, but the primary products of this type of decomposition are methane and hydrogen gas that can be used as fuel.

In the United States alone, cows and other livestock animals create over a billion tons of manure a year—manure which is left to decompose outdoors, creating greenhouse gases and harmful airborne and waterborne pollutants. An ample opportunity exists for dairy and livestock farms to both curb greenhouse emissions and produce alternative forms of energy that can be accomplished through anaerobic decomposition, which requires machines called anaerobic digesters.

However, the process of anaerobic digestion is costly, so local electric utilities are partnering with farmers to cover the cost of conversion and companies are now developing scalable anaerobic digesters that can convert the methane on relatively small farms in ways that are affordable for farmers and ultimately benefit everyone. The power generated by these small farms can not only be used to run the farm, but can also be sold back to local utilities so that the surrounding neighborhoods can have affordable power for their homes.

For more information on cow power go to:

Environmental Leader,
"PG&E Gets Energy from Cow Manure":

Explain That Stuff, 
"Climate Change and Global Warming":
National Geographic, 
"Cow Manure, Other Homegrown Energy Powering U.S. Farms":

Animation by Stephen Blauweiss

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