Duke Energy last week began generating electricity in eastern North Carolina with natural gas from a new source: hog waste. It helps Duke meet a state mandate, while benefiting farmers, too.
The hogs starring in this new role are at five farms in Duplin County, east of Fayetteville. Waste is flushed into an underground tank called a digester, which captures methane gas. Pipes carry that to a bio-waste converter, where it's processed into pipeline-quality gas. From there, it's fed through a Piedmont Natural Gas pipeline to a Richmond County power plant - where it will be burned for electricity.
"This is the first of its kind in North Carolina where we're taking the renewable natural gas and shipping it to a large existing power plant that can be put in their energy mix,” Duke spokesman Randy Wheeless said.
It’s not the first time hog waste has been used for energy. Duke currently contracts with out-of-state farmers for some hog-generated gas. This is the first time North Carolina hogs are being used.
Meanwhile, some North Carolina farms use methane from hogs in small on-site power generators. Wheeless said Duke’s system allows the gas to be used more efficiently in Duke’s much larger electric plants.
The converter is run by a company called Optima KV under a 15-year contract Duke announced in 2016. Duke has at least one other similar project in the works.
Farmers get paid for the hog waste. Wheeless said it's also more environmentally friendly than the current situation - open lagoons that let methane escape into the air.
“Farmers want to minimize their impact on the environment," Wheeless said. "That's a big issue in eastern North Carolina."
Duke is working on hog waste projects like this to comply with a state law that requires the company to generate 0.2 percent of its electricity with hog waste by 2021.
This plant is a baby step to eventually generating 11,000 megawatt hours of electricity – enough to power a thousand homes.