Pig Power: How Two Dukes, And Google, Do It

Remember our story about Google and its Green Blog post that detailed how carefully it scopes out projects that it supports with its carbon offsets program? Well, one of the projects mentioned in that post is taking advantage of its time in the big Google spotlight, noting the search giant’s support and sharing details about the effort to reduce greenhouse gas emissions while turning hog waste into energy.

The three-years-in-the-making, pig-poop-to-power prototype is run by a couple of Dukes – Duke University and Duke Energy (James Buchanan Duke was instrumental in founding both) – with financial assistance also coming from federal and state sources. And, of course, Google is taking on a share of the costs for carbon offers for a five-year term.

hog farm waste to energy plant, Google, Duke

image via Google

Those carbon offsets exist because at Loyd Ray Farms, a 9,000-head hog finishing farm about 25 miles west of Winston-Salem, N.C., the greenhouse gases from hog waste are captured and burned, keeping about 5,000 meteric tons of CO2 – the annual output of about 900 cars – out of the atmosphere every year, the university said. The system works by using a lined and covered anaerobic digester and a lined aeration basin. “Methane gas is collected under a thick plastic dome over the digester,” the university says, and gas that isn’t burned in the turbine “is burned in a flare to prevent its release.”

hog farm waste to energy, Google, Duke

image via Google

And in addition to destroying the methane, the system powers a microturbine that produces electricity to run the operation, with leftover electricity going to the farmer to use in his regular farm operations. Loyd Ray’s bill is said to be down $1,000 a month since the system went in. Two other benefits to the system: healthier pigs, because ammonia in the barns is reduced; and cleaner flush water that can be used to help grow row crops.

The university hopes to see this system adopted widely, and though it cost $1.2 million to develop, has some reason to suspect it might: It was built with “off-the-shelf technology” and the design is “open source” – meaning it can be freely adopted and implemented at other hog farms.

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Pete Danko is a writer and editor based in Portland, Oregon. His work has appeared in Breaking Energy, National Geographic's Energy Blog, The New York Times, San Francisco Chronicle and elsewhere.