Study evaluates strategies for generating electricity from hog waste

Apr 26, 2013

( —Capturing methane gas from hog farms and piping it into existing natural gas pipelines may be a cost-effective way to meet North Carolina's Renewable Energy and Energy Efficiency Portfolio Standard (REPS), according to a new Duke University study.

A modeling analysis by researchers at Duke's Nicholas Institute for Environmental Policy Solutions and the Duke Initiative compared individual farm and centralized approaches for meeting the swine mandate in the state's REPS. It found that electricity could be generated at costs of approximately 11 cents per kilowatt hour at individual farms and between 6 and 11 cents per if hog farms were to use a central line to transport for pipeline injection through an approach known as "directed biogas."

The analysis found that a network of farms in Duplin and Sampson counties, where swine farming is most concentrated, appear to be the best candidates for producing swine waste-derived energy.

The researchers note however, that cost projections were limited to costs of construction, equipment, operation and maintenance. Ultimate prices for electricity from swine waste would be affected by other costs not addressed in the study, such as business development.

"The intent of this report was to remove a lot of the guesswork from where and how to best pursue swine waste to energy," said Tatjana Vujic, director of the Duke Carbon Offsets Initiative and report co-author. "Duke's analysis also indicates that the costs of swine-based renewables aren't far off from other renewables. Basically, converting swine waste into energy is within reach."

Under a North Carolina law approved in 2007, utilities were supposed to get some of the electricity they sell—.07 percent now and .20 percent by 2018—from hog waste each year. So far, little of the set-aside has been met.

This study provides a first step, the authors said, toward an informed strategy to increase swine gas in the state. They found that of the approximately 2,126 swine farms in North Carolina, as few as 7 percent would need to participate to meet the REPS mandate.

The most cost-effective of four scenarios examined by the study would use a farm located near the natural gas pipeline to collect gas from nearby hog operations, process it, and then feed the biogas into the existing natural gas pipeline. To nearly double efficiency, farms would use new, covered digesters rather than existing lagoons to generate biogas.

In addition to the cost savings and income potential from , the capture and destruction of swine waste-derived biogas could reduce the state's greenhouse gas emissions by as much as 1.37 million metric tons per year by 2018. New capture systems could also pave the way for system add-ons that would help farms improve their environmental performance, and possibly expand their operations.

"The potential to reduce greenhouse gases from North Carolina's swine sector is significant —meeting the REPS target alone would be the equivalent of taking 285,000 cars off the road each year," Vujic said. "What's more, the revenue from carbon offsets achieved by those emission reductions can be sold in markets such as California's cap-and-trade system, which represents additional income that could make pursuit of swine waste to energy even more attractive."

The authors caution that more work is needed to identify additional costs of developing swine waste to as well as incentives that could bring its costs down before locking in on an actual price.

Explore further: Switch on sunlight for a brighter future

More information:

add to favorites email to friend print save as pdf

Related Stories

Hog waste producing electricity and carbon offsets

Sep 08, 2011

A pilot waste-to-energy system constructed by Duke University and Duke Energy this week garnered the endorsement of Google Inc., which invests in high-quality carbon offsets from across the nation to fulfill ...

Improving swine waste fertilizer

Jul 08, 2008

Swine production generates large amounts of waste. While this waste contains nutrients that may serve as fertilizer when applied to agricultural fields, the ratio of nutrients in the waste is different than what a crop requires.

Chicken waste turned to watts

Dec 26, 2009

A Nevada energy developer says it has developed an environmentally clean way of using animal waste from chicken farms across the state to light up homes and offices. Green Energy Solutions wants to convert ...

Environmental impact of animal waste

Mar 04, 2011

North and South Carolina have seen a steady increase in swine production over the last 15 years. In North Carolina alone, swine production generates approximately a quarter of the state's gross farm receipts. ...

Recommended for you

Switch on sunlight for a brighter future

2 hours ago

Imagine sitting in a windowless room yet having the feeling of the sun shining on your face. This unique experience is now possible thanks to the COELUX EU-funded project which recreates the physical and ...

US urged to drop India WTO case on solar

18 hours ago

Environmentalists Wednesday urged the United States to drop plans to haul India to the WTO to open its solar market, saying the action would hurt the fight against climate change.

Is nuclear power the only way to avoid geoengineering?

Apr 23, 2014

"I think one can argue that if we were to follow a strong nuclear energy pathway—as well as doing everything else that we can—then we can solve the climate problem without doing geoengineering." So says Tom Wigley, one ...

Finalists named in Bloomberg European city contest

Apr 23, 2014

Amsterdam wants to create an online game to get unemployed young people engaged in finding jobs across Europe. Schaerbeek, Belgium, envisions using geothermal mapping to give households personalized rundowns of steps to save ...

Bloomberg invests $5M in solar-powered lamp

Apr 22, 2014

Former New York Mayor Michael Bloomberg's foundation has announced a $5 million investment in an artsy-looking solar-powered lamp designed for use in off-grid populations in Africa.

User comments : 2

Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Apr 26, 2013
Don't you think some Virginia environmentalists might object to a pipeline running waste from D.C. down to North Carolina?
not rated yet Apr 26, 2013

More news stories

New breast cancer imaging method promising

The new PAMmography method for imaging breast cancer developed by the University of Twente's MIRA research institute and the Medisch Spectrum Twente hospital appears to be a promising new method that could ...

Research proves nanobubbles are superstable

The intense research interest in surface nanobubbles arises from their potential applications in microfluidics and the scientific challenge for controlling their fundamental physical properties. One of the ...

Using antineutrinos to monitor nuclear reactors

When monitoring nuclear reactors, the International Atomic Energy Agency has to rely on input given by the operators. In the future, antineutrino detectors may provide an additional option for monitoring. ...