NC poised to be a leader in bioenergy 

by | Apr 14, 2021

In 2018, North Carolina produced its first natural gas. This gas came from pig farms.  

Eastern North Carolina is dotted with pig farms, with the state ranking second in the United States in the production of hogs. It is no surprise that the first biogas operation is located in the heart of these swine operations, Duplin County.

Currently five farms have covered digesters, which are synthetically lined lagoons with thermally welded covers placed on top that can expand or contract with the amount of gas being produced. The digesters create an oxygen-free home that is the best environment for the specific bacteria that consumes the manure in the covered lagoon and then expire biogas. This captured gas is about 65 percent methane, a major constituent of natural gas. The biogas is then piped to a local, central upgrade station where it is refined and injected into the natural gas pipeline before being sent to homes and businesses as energy.

The gas leaves farm at a pressure of 5 PSI (for reference – most car tires are filled to around 35 PSI) and a central gas upgrading system (above) must get the gas to 1,000 PSI for use in the pipeline.

Current energy produced from the state’s five digesters equal enough energy to power two towns the size as Kenansville. The N.C. Department of Environmental Quality recently approved another project with four more farms. According to Gus Simmons, director of bioenergy for Winston-Salem based Cavanaugh and Associates, which focuses on bioenergy solutions, the potential for more is tremendous.

“Capturing biogas from these farms significantly reduces the state’s greenhouse grass emissions,” Simmons said. “It is actually one of the cleanest, most carbon negative fuels that we can consume as a country.”

According to the National Pork Producers Council, the swine industry is not a large producer of greenhouse gases. The U.S. swine herd contributes only .4% of the total greenhouse gas emissions in the country. However, since North Carolina pig farms use anaerobic lagoons which emit a small amount of methane and carbon dioxide, it makes sense to capture it and use it as a renewable energy source that diversifies North Carolina’s energy portfolio.

“Currently in North Carolina our energy is imported,” Simmons said. “This project provides a local source of energy and guards against supply disruptions for our critical industries.  North Carolina could easily be one of the top three richest states in renewable energy.”

More than half of U.S. states have biogas projects, with more under consideration every day as states begin to realize the potential of this renewable energy source. North Carolina has an advantage in that our mild winters allow for year-round methane production versus Midwest states where anaerobic bacteria fall dormant for five or six months out of the year.

“We believe that this approach that captures the biogas from agricultural practices not only strengthens the ag sector but provides assurances to the energy sector,” Simmons said.

Engineers Kraig Westerbeek, of Smithfield Foods, and Gus Simmons, of Cavanaugh, standing on the synthetic liner of a digester at a Duplin County farm.

In 2016, Virginia-based Smithfield Foods was one of the first swine production companies in the country to set up a carbon reduction goal. At the time its goal was a 25% reduction in emissions in 25 years. The company reviewed its carbon footprint from grain production to pork consumption. A large portion of their carbon footprint comes from manure management.  

“These projects help us meet our ’25 by 25′ goal,” said Kraig Westerbeek, senior director of Smithfield Renewables. “We are really investing in manure-to-energy. Our hope is that 90 percent of finishing farms in eastern North Carolina would have manure-to-energy projects on them in the next 10 years. We think it is great technology and great for farmers. It is also great for the communities where these farms are located.”

“We have figured the technology out,” he added. “One of the key tenets is getting fresh manure into a digester. With our projects here in North Carolina, we offer the farmer an opportunity to install a digester and mixing pumps and then Smithfield invests in pipeline and the gas upgrading system.” Farmers are given a long-term contract on the gas produced, which helps them make a return on their investment. The project is voluntary and any pig farmer in the area is eligible to participate whether or not they are contracted with Smithfield.

“When I look at these projects, I think they make all the sense in the world,” Westerbeek said. “I understand that people have apprehension about something new, but when you stand here and see what we are doing I think you can see the opportunity NC has to be a leader in renewable energy in the United States.”

This video was made in partnership with the N.C. Pork Council and NCDA&CS and made possible by a grant from the NC Tobacco Trust Fund Commission.