NREL Document Profiles Natural Gas Fueling, Fleet Operation

Steve Ginter, Mack, 610-709-3259

Golden, Colo., June 7, 2000 - A unique and successful natural gas fueling and fleet operation involving trash haulers is discussed in a recent document issued by the U.S. Department of Energy's National Renewable Energy Laboratory (NREL).

The NREL document, Waste Management's LNG Truck Fleet Start-Up Experience, offers solid evidence that LNG-powered vehicles can handle the demands of a refuse collection operation. The document focuses 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. The document tracks Waste Management's LNG program from concept to start-up to present-day operation, describing the vehicle, engine and fueling station technologies used in the project as well as the early performance of the station and vehicles. Members of the project team also share some of the lessons they learned.

The LNG trucks have gained enthusiastic support from drivers, according to Ben Woods, district manager for Waste Management. Having overcome initial reservations about the new technology and the specialized fueling and safety training it requires, many drivers now prefer the LNG trucks, he says. "It's not a matter of encouraging or persuading them. We can't get them out of the trucks."

Drivers like the LNG trucks for several reasons: no diesel smoke, no diesel smell, less engine noise and more power for heavy payloads (the LNG units have 325-hp engines while the diesel vehicles have 300-hp engines). And because drivers fuel their own vehicles, they like not having to wait in line for diesel fuel.

Seven Waste Management refuse haulers currently rely on the station for LNG fuel. All seven 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 is different than a comparable diesel model in several respects. For example, it has different pistons and cylinder heads than a diesel model and uses a homogeneous, lean-burn fuel delivery system for optimum combustion. Mack's latest E7G natural gas engine is certified to the U.S. Environmental Protection Agency's low-emission vehicle (LEV) standard as well as the California Air Resources Board's Low-NOx (oxides of nitrogen) standard for heavy-duty applications.

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

A colorless, odorless, non-toxic, non-corrosive and non-carcinogenic fuel, LNG is natural gas cooled to approximately -260°F at atmospheric pressure. Because 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 NOx.

NREL objectively evaluates the performance, emissions and operating costs of alternative fuel vehicles (AFVs). The laboratory provides its findings in publicly available documents, helping current and potential users make informed decisions about whether or not to purchase AFVs.

The document 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 available on DOE's Alternative Fuel Data Center Internet site or through the National Alternative Fuels Hotline at 800-423-1DOE.

Photographs and additional information about the Waste Management natural gas truck project are available on request.

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