Hog farms try collecting gas, making energy

At this factory farm that houses more than 10,000 hogs, a black plastic tarp covering part of a hog waste pond swells with untapped opportunity.

Captured beneath the bulging cover is methane gas, which rises off the pond as manure decomposes. It is a potent greenhouse gas trapping heat in the Earth’s atmosphere. But methane can also fuel an incinerator or drive a turbine to produce electricity.
The prospect of using the combustible gas to cut greenhouse emissions and produce revenue is drawing interest from entrepreneurs and agricultural companies.

To explore methane’s potential, Murphy-Brown, a subsidiary of Smithfield Foods, spent about $120,000 enclosing 20 percent of a 7-acre lagoon on Company Farm 2039 in Sampson County.

“We want to fully understand the potential for energy production from our farms,” said Don Butler, director of government relations at Murphy-Brown, as he surveyed the tarp. “Methane is the one we believe has near-term potential.”

Right now, the captured gas at the Murphy-Brown farm is pumped out when needed to fire an incinerator to cremate two to six dead hogs a week. The rest is burned off, creating carbon dioxide — a gas that is far less damaging as a greenhouse generator than methane.

Eventually, Butler said, company officials hope to produce electricity from the methane to sell to utilities.

Lawmakers encouraged the concept by approving legislation last week creating a pilot program to generate up to 25 megawatts of power from captured methane on 50 farms — enough to power about 15,000 homes.

News Observer