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Liquid Natural Gas Operation Impresses Trash Haulers

The verdict is in: A study of natural gas fueling and fleet operations finds trash haulers prefer fueling with natural gas instead of diesel.

According to the U.S. Department of Energy's National Renewable Energy Laboratory, which conducted the study, LNG-powered vehicles can handle the rugged demands of a trash collection operation. The Laboratory recently released a report focusing on a Waste Management landfill operation in tiny Washington, Pa., that since 1997 has housed a liquefied natural gas (LNG) fueling facility and several LNG-powered refuse haulers.

Ben Woods, district manager for Waste Management, says his drivers enthusiastically support LNG-equipped trucks. Having overcome initial reservations about the new technology and the specialized fueling and safety training it requires, many drivers now prefer the LNG trucks, Woods says.

"It's not a matter of encouraging or persuading them. We can't get them out of the trucks."

According to Woods, drivers say they like the LNG trucks for their lack of diesel smoke and smell, their quieter engines and increased power for heavy payloads (the LNG units have 325-hp engines while the diesel vehicles have 300-horsepower engines). And as drivers fuel their own vehicles, Woods says, they like not having to wait in line for diesel fuel.

Rough terrain

Seven Waste Management refuse haulers rely on the new station for LNG fuel. All trucks are equipped with second-generation Mack E7G natural gas engines. The LNG trucks operate in the same tough duty cycle as Waste Management's 143 diesel trucks, making as many as 900 to 1,000 stops each day on city and suburban routes.

The Mack E7G natural gas engine differs from a comparable diesel model: it has different pistons and cylinder heads than a diesel model and uses a homogeneous, lean-burn fuel delivery system for optimum combustion.

Anything but typical

At first glance, Waste Management's Washington site looks like any other landfill. However, it's anything but typical. Buried 8.5 feet below the site hulks a 13,000-gallon LNG storage tank. A single fuel dispenser provides up to 30 gallons of LNG per minute.

LNG, a colorless, odorless, non-toxic, non-corrosive, and non-carcinogenic fuel is natural gas cooled to approximately -260°F at atmospheric pressure. As it must be cold to remain a liquid, LNG is stored in double-walled, vacuum-insulated containers for dispensing into a vehicle. When used in vehicles, it can provide reductions in emissions of reactive hydrocarbons, particulate matter and nitrous oxide.

The DOE report, Waste Management's LNG Truck Fleet Start-Up Experience, is one of a series of NREL documents from DOE's alternative fuel truck evaluation project. Those documents will be made available on DOE's Alternative Fuel Data Center Web site or through the National Alternative Fuels Hotline at 800-423-1DOE.

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