Renewable Natural Gas from Landfills Can Reduce Fuel Costs and Increase Independence

For more than a decade, Vogel Holding in western Pennsylvania has turned trash into energy by capturing methane from its Seneca Landfill and processing it into renewable natural gas (RNG) to fuel the company's waste collection trucks.

RNG can be used in natural gas vehicles (NGVs), maintaining power and fuel economy while reducing emissions. Fleets that produce their own RNG, like Vogel, can also save money and reduce dependence on external fuel suppliers.

"Because we're making our own fuel, we reduce our fuel costs every time we replace a diesel-fueled vehicle with one that runs on renewable natural gas," said David Smith, Seneca Landfill general manager. "We reduce our costs because we're not purchasing diesel."

RNG is the gaseous product of decomposing organic matter that has been upgraded to remove non-methane elements. It is fully interchangeable with conventional natural gas, and compressed RNG can be used as a drop-in fuel for NGVs.

Vogel produces 525 million cubic feet of RNG per year, according to Smith, more than enough to fuel all 150 of their NGVs. Fleet vehicles running on RNG include waste collection trucks, tractor trailer transfer trucks, triaxle dump trucks, and service vehicles.

"We look at ourselves as a renewable energy facility," Smith said. "What we collect today in garbage helps fuel us tomorrow."

Benefits of Natural Gas as a Vehicle Fuel

Whether conventional or renewable, natural gas as an alternative vehicle fuel brings the benefits of domestic availability, relatively low cost, and lower emissions. Replacing conventional diesel or gasoline vehicles with NGVs can reduce emissions of nitrogen oxides and particulate matter, resulting in improved local air quality.

The price of compressed natural gas (CNG) is historically more stable than gasoline or diesel and can be less expensive than those fuels. According to the October 2024 Alternative Fuel Price Report, CNG costs about 35 cents less than diesel on a per diesel gallon equivalent basis, and 34 cents less than gasoline on a per gasoline gallon equivalent basis.

Heavy-duty natural gas vehicles, like refuse trucks, are available from domestic manufacturers (use the Alternative Fuels Data Center's Alternative Fuel and Advanced Vehicle Search to identify vehicle options). Those looking to transition to NGVs also have the option of converting existing gasoline or diesel vehicles to run on natural gas.

Capturing Landfill Biogas for RNG

Landfills are a source of RNG from organic matter—such as food waste, grass clippings, and leaves—breaking down to produce methane, carbon dioxide, and water vapor. At Vogel's Seneca Landfill, sealed cells capture the methane, then a system of wells and pipes are used to siphon the gas from the landfill and transport it for processing.

"We get the best gas quality by capping soon after waste starts producing landfill gas," Smith said. "Some companies may wait before capping, but if we build a five-acre cell, we cap five acres. You're giving yourself a better chance to collect all the gas and avoid odor issues by capping often."

To capture the methane, Vogel drills vertical wells every 80 feet along stormwater benches about 150 feet apart. Six-inch diameter perforated pipe pulls the gas out of the landfill, with vertical pipes tied to lateral pipes that run around the landfill and into the wells.

"I like to explain it like an apple pie," Smith said. "Your crust at the bottom is an extensive plastic liner, and then at the top there's another liner that encapsulates the garbage, which is your filling, with waste columns that can reach 200 to 250 feet."

The piping system ultimately transports unprocessed landfill gas to a high-BTU processing facility where hydrogen sulfide, water, and other contaminants are removed. Once the gas is refined, it's piped to a vehicle fueling station. Seneca uses a fast-fill station, allowing trucks to fill up within 15 minutes— "the same amount of time it would take them to fill up a 90-gallon diesel tank," Smith said.

In addition to fast-fill, there are two other types of CNG fueling stations: time-fill and combination. Time-fill stations slowly fuel vehicles, typically overnight. While this method takes longer, time-fill stations result in a fuller fill than fast-fill because less heat is generated during compression. Combination-fill stations include both fast-fill and time-fill components in a single system, providing flexibility for fleets with different needs.

Distributing Excess RNG

Approximately 2,400 cubic feet of landfill gas are extracted every minute from Seneca, Smith said, resulting in 525 million cubic feet of RNG produced every year. This amount of fuel exceeds Vogel's needs, enabling the company to distribute surplus gas.

Vogel has multiple tube trailers—long cylindrical pressure receptacles stacked and secured on a semitrailer—to create a "virtual pipeline" that transports RNG from Seneca to publicly accessible CNG fueling stations in Mars, Grove City, and Beaver Falls, Pennsylvania.

"If someone wants renewable natural gas, we have the ability to transport it to them in those containers," Smith said.

Demand for transported RNG is currently limited, but Vogel supplies the fuel for the University of Pittsburgh Medical Center's employee transit buses. "We're working on trying to expand," Smith said. "It requires licensed commercial drivers, so we'd need more of those."

Purchasing CNG Vehicles

Vogel purchased its first eight CNG waste haulers in 2011 with a Diesel Emissions Reduction Act (DERA) Program grant from the U.S. Environmental Protection Agency. The grant proposal was submitted as part of a federation of local businesses spearheaded by Pittsburgh Region Clean Cities (PRCC), a coalition in the Clean Cities and Communities partnership. The group received $888,750 to replace 17 heavy- and medium-duty highway diesel vehicles with CNG vehicles.

"The DERA grant was brought to us by Equitable Gas Company," said Richard Price, executive director of PRCC. "There was a minimum amount you had to apply for, which Equitable didn't meet on its own. So, we combined the needs of the gas utility with those of Giant Eagle, which is a regional grocery chain that runs a lot of Class 8 tractor trailers, and with those of Vogel waste disposal, and we got the grant."

PRCC is one of more than 75 U.S. Department of Energy-designated Clean Cities and Communities coalitions across the country. These coalitions work with fleets, government entities, and other organizations to identify locally driven projects that advance affordable and efficient transportation fuels and technologies in the regions they serve. Smith said PRCC is integral in promoting the work Vogel does with RNG.

"They help collaborate and promote CNG in a lot of ways," Smith said. "They conduct trainings on natural gas and other alternative fuels. They invite us to present on our RNG work at their biggest annual event, Odyssey Day, which offers talks and activities that promote alternative fuels and advanced technology vehicles. PRCC really gets the word out to people that Vogel is a renewable gas source."