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 Carbon Offsets 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 kilowatt hour if hog farms were to use a central line to transport biogas for pipeline injection through an approach known as "directed biogas."
The analysis found that a network of farms in Duplin and Sampson counties 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 study was funded by Duke Energy Carolinas and the Environmental Defense Fund. To read it, visit here.