Hog Farms Try Collecting Gas, Making Energy
CLINTON — 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.”
Covered animal-waste lagoons are rare in the United States but prevalent in some countries that limit greenhouse emissions. They might become more common in the United States, too, if Congress imposes caps on greenhouse gases in the next few years, as some expect.
That could create a “carbon” economy, giving value to cutting greenhouse emissions and creating a market for credits on such reductions.
Last month, American Electric Power, one of the nation’s largest power producers, announced the first large-scale program to capture methane from about 200 livestock operations in 11 states from Virginia to Ohio.
Some environmentalists say partially covering lagoons to capture methane treats only one problem: methane emissions. It does not address such issues as odor, ammonia emissions and other pollutants that have long been a problem on factory farms.
“We have a lot of concern about industry taking that route,” said Joe Rudek, a senior scientist with the North Carolina office of Environmental Defense, a national advocacy group. “When you collect methane, you’re just dealing with the carbon in the waste. The problems come from the other pollutants.”
Opportunity in N.C.
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.
North Carolina is the nation’s second-largest hog-producing state with more than 9 million hogs on 2,300 farms, primarily in Eastern North Carolina. Entrepreneurs see opportunity to get in on the carbon economy by using the waste from those farms.
Scott Subler, president of Environmental Credit Corp., a Pennsylvania-based supplier of environmental credits to financial markets, spent several days last week canvassing pork producers in North Carolina, looking for farmers willing to let his company install tarps on lagoons.
In June, Environmental Credit received a $1 million grant from the U.S. Department of Agriculture to install covers on New York dairy farms and North Carolina hog farms to reduce greenhouse gas emissions. Subler said the company wants to sign 10-year contracts with eight to 10 farms in North Carolina and invest about $1 million in grants and private money.
“We come in and will pay to have manure lagoons covered with high-strength plastic cover,” he said. “The farmers receive a guaranteed annual payment.”
Greenhouse gas trades
The captured greenhouse emissions are tracked by engineers and converted mathematically into carbon credits, giving each ton of captured greenhouse gas a monetary value. The credits are bought and sold on the Chicago Climate Exchange, a private agency that trades greenhouse gases just as other exchanges trade such commodities as livestock. Environmental Credit expects the credits’ value to increase over time.
Duke University, in partnership with Duke Energy, the power company, and a London-based investment firm, might also get involved. They are trying to identify hog farms where the sale of greenhouse gas credits, renewable energy and other waste products will attract private investment to convert hog lagoons to better waste-handling systems.
“We are not choosing a technology to see if it’s going to work,” said Bill Holman, senior fellow at Duke’s Nicholas Institute for Environmental Policy Solutions. “We’re trying to look at a whole suite of technologies.”
Researchers say that fully covered lagoons do help reduce odors and ammonia emissions, though not as much as some innovative technologies such as those that produce electricity from methane after fully treating the waste. Partial covers are unlikely to have those additional benefits.
Mike Williams, director of the Animal and Poultry Waste Management Center at N.C. State University, said it isn’t reasonable to expect that large numbers of swine farms would replace their open-air holding ponds until new treatment systems become economically feasible.
In the meantime, Williams said, capturing emissions is a positive step, even if the covers don’t address other pollutants. He said that capturing methane from North Carolina hog farms — if all participated — could produce enough electricity to power about 50,000 houses.
“For us to also have an opportunity to reduce greenhouse gases, which is a significant concern, I think that is a good thing to do,” Williams said.
Staff writer Wade Rawlins can be reached at 829-4528 or firstname.lastname@example.org.