Methane Capture: Agri-Alchemy

In a recent summary report from the Food and Agriculture Organization of the United Nations (Livestock's Long Shadow), trillions of farm animals across the globe were found to generate a whopping 18% of CO2 emissions. That is more than cars, buses, and airplanes. Hard to swallow that flying could reduce your carbon footprint more than eating meat, but as the New York Times put it: "Flatus and manure from animals contain not only methane, but also nitrous oxide, an even more potent warming agent. And meat requires energy for refrigeration as it moves from farm to market to home." ("As More Eat Meat, a Bid to Cut Emissions," Dec 3, 2008.)

A pig farm in Sterksel, Netherlands has begun cooking its manure (3000 pigs worth) to capture the methane trapped within. The (bio)gas is then, in turn, used to generate electricity for the local power grid. And this is now becoming a growing trend as environmentally responsible agri-businesses try to curtail emissions. Without this activity the pig manure would be stored in open storage tanks for about 6-9 months before being used as fertilizer for farm lands. Cattle and pig manure, when kept in open-top basins, tanks or lagoons open to the atmosphere, undergo anaerobic fermentation and release greenhouse gases (methane, CO2 and N2O) to the atmosphere, not to mention the potent aroma.

To make matters more complicated, the growing demand for meat, has lead to a need for more farm feed, especially soy, which is increasingly supplied by forest clearing. Therefore essential "carbon sinks" are being removed to make way for the release of harmful methane.

Several countries have already implemented mandates for methane reduction. In Denmark, farmers are required by law to inject manure under the soil instead of on top of fields, which enhances its fertilizing effect and prevents emissions from escaping. And New Zealand recently announced that it would include agriculture in its new emissions trading (scheme by 2013. To that end, the government is spending tens of millions of dollars financing research and projects like breeding cows that produce less gas and inventing feed that will make cows belch less methane.

Other uses for methane capture and biogas have found their into transportation, such as Biogasmax (buses) and Svensk Biogas (rail).

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