Hardly Hogwash

Pilot project to capture methane gas, address greenhouse effect
June 9, 2013

Waste not: Experimental project will transform hog byproduct into a fuel source. Credit: Karl Bates

Duke and regional utility company Duke Energy are working together to turn hog waste into power, while at the same time, offsetting carbon consumption.

In early fall, construction began on a prototype system for capturing methane gas that was planned and is being built with support from the university, the energy company, and state and federal agencies. The $1.08 million system is being built at Loyd Ray Farms, a 9,000-head hog farm in Boonville, North Carolina.

Under normal circumstances, waste from the hog processing operation goes into a lagoon, where it emits methane gas into the environment. This system captures the gas after the waste goes through a lined and covered anaerobic digester and a lined aeration basin.

Methane gas contributes twenty-one times as much greenhouse gas as does carbon dioxide. But unlike carbon dioxide, methane is an efficient fuel source. Gas collected from the digester will be used to run a turbine that will generate up to 639 megawatt-hours of energy a year. Methane is burned to power a turbine in the same way burning gasoline pumps pistons in an internal combustion engine.

Capturing the methane also will create carbon-offset credits for the university and generate renewable energy credits for Duke Energy.

In exchange for participating in the experimental pilot project, farmer Loyd Bryant, who switched from raising tobacco and beans to hog farming in 1998, will keep the infrastructure at no cost. After ten years, he will own the system free and clear.