From trash to fuel: Inside a North Carolina renewable natural gas plant

The mountains of trash outside Roseboro are producing more than just waste.

At a new facility in Sampson County, methane released from decomposing garbage is being captured, cleaned and converted into renewable natural gas used to power heavy-duty trucks.

Congressman Greg Murphy toured the facility Wednesday, calling the project part of an “all-of-the-above” energy strategy as North Carolina faces growing energy demand.

“The fact that we're able to actually use energy from sources that are renewable is a win-win for everybody,” Murphy said. “The fact that you're already creating a substance [landfill methane] and it can be transferred and used for big engines is critical, and the fact that we're doing it here in eastern North Carolina is paramount.”

As organic waste breaks down in landfills, it produces methane — a greenhouse gas scientists say is significantly more potent than carbon dioxide in the short term.

OPAL Fuels Co-CEO Adam Comora said the facility uses a network of underground pipes to collect that gas before it escapes into the atmosphere.

“What we do is we drop in pipes … apply a little bit of suction vacuum, so that we’re pulling all the biogas into our plant here, rather than it venting off into the atmosphere,” Comora said.

Inside the plant, the gas is chilled and pushed through membranes that separate methane from other impurities. The methane is then purified to pipeline quality natural gas.

The facility began operating in November 2024 and can produce enough renewable natural gas annually to replace about 6.5 million gallons of diesel fuel, according to OPAL Fuels.

The company says that amount could fuel roughly 650 garbage trucks or up to 350 long-haul tractor trailers.

Comora said renewable natural gas is increasingly being used in heavy-duty trucking because it is typically cheaper and cleaner than diesel fuel.

“Not only are you taking methane that would have vented or escaped off into the atmosphere, you’re also deploying a much cleaner technology on the back end,” he said.

Murphy said renewable natural gas could play a growing role in North Carolina’s energy future as the state grapples with rising electricity demand tied to population growth, manufacturing and data centers.

“We’re going to need everything that we can to supply our energy needs,” Murphy said.

While renewable natural gas projects are generally viewed as preferable to allowing methane to escape directly into the atmosphere, some environmental advocates and researchers have raised concerns about methane leakage throughout gas infrastructure systems and whether RNG should be viewed as a long-term climate solution.

Comora said the company uses gas monitoring systems and requires workers to wear methane detection monitors throughout the facility.

“We’re trying to capture every molecule that we can,” he said.

The company also uses flare systems designed to burn off excess or off-spec gas during maintenance or operational disruptions.

According to OPAL Fuels, the company has invested more than $65 million into the Sampson County project.

The company is also developing another roughly $100 million renewable natural gas project connected to Charlotte Motor Speedway expected to begin operating next year.