What's Fueling Your Fleet?

Sean Kilcarr, Senior Editor

March 1, 2003

15 Min Read
What's Fueling Your Fleet?

As regulations force waste haulers to operate trucks on alternative fuels to reduce air pollution, many will be walking a fine line to balance increased equipment costs while maintaining a more environmentally friendly fleet.

Refuse fleets are beginning to face an unpleasant reality as nationwide efforts to reduce air pollution force many waste companies to power their fleets with alternative fuels.

While there are several alternative fuels to choose from — natural gas, biodiesel, propane and electricity, among others — only the first two currently provide the power and torque necessary to operate heavy-duty refuse trucks. Some say using natural gas or biodiesel could substantially raise the cost structure of today's refuse fleet. Yet there also are opportunities, over time, for those alternative fuels to eventually lower operational costs. This has many refuse fleets walking a tightrope.

Arlington County, Va., for example, recently began using an alternative fuel to combat rising pollution levels in and around Washington, D.C. Although the area lacks heavy industry, a recent analysis by transportation planners at the Metropolitan Washington Council of Governments found that the region around the nation's capital is expected to exceed vehicle exhaust pollution limits this year by 30 percent, largely due to increasing numbers of sport-utility vehicles, pickups and diesel trucks.

If air pollution levels — primarily from vehicles — are not reduced in accordance with federal laws passed in the 1990s, federal funds earmarked for road construction and maintenance will be cut back. This has created heavy pressure on many commercial fleets in the area, especially refuse haulers, to cut vehicle emissions.

“We're in what's called a ‘non-attainment’ area for air pollution, so we are trying to reduce our fleet's emissions to meet those requirements,” says F.I. “Ric” Hiller, chief of the equipment division for Arlington, a county of 190,000 people located just south of Washington. Consequently, all of the county's 500 vehicles — 20 percent of which are refuse trucks — now operate on B20: a blend of 80 percent regular diesel fuel and 20 percent biodiesel, which is made from soybeans instead of petroleum.

“We started using B20 in all our diesel-powered vehicles because we saw an opportunity to kill two birds with one stone: clean the air and use a renewable fuel,” Hiller says. Using B20 has cut fleet particulate emissions by 22 percent and carbon monoxide levels by 20 percent, although Hiller says the fuel increased nitrogen oxide (NOx) emissions by 2 percent. That increase in NOx is largely because the organic portion of biodiesel, when burned in the engine, releases more NOx, according to studies by the Southwest Research Institute of Texas, San Antonio. That group also noted that the higher the amount of biodiesel within the blended fuel, the more NOx is produced.

Nevertheless, the county is pleased with biodiesel — even if the fuel costs 16 to 24 cents more per gallon than regular diesel and requires an additive package to prevent it from solidifying during cold weather.

“There's a major, major cost difference between natural gas technology and straight diesel or biodiesel options, so we're still waiting to see how that price differential works out in the future,” Hiller explains. “However, I think long term we'll have to look at using other alternative fuels as pressure to cut emissions gets stronger.”

Currently, Arlington is using natural gas in some of its light vehicles but not in heavy trucks, because the county is not mandated to do that yet, Hiller notes.

Emission Pressure

Federal and state regulations have pushed communities to cut emissions in the past decade — and refuse fleets frequently are finding themselves in the crosshairs of those efforts.

In 1990, Congress amended the Clean Air Act (CAA), calling for vehicle fleet emissions reductions. Those rules affected federal, state, municipal, fuel provider and private fleets operating in cities with more than 250,000 people and whose air quality was classified as extreme, severe or serious nom-attainment for ozone-causing emissions and carbon monoxide. In all, some 133 million people in the nation are considered to be living in areas that violate the new air quality standards.

As part of the new rules, the U.S. Environmental Protection Agency (EPA), Washington, D.C., was charged with developing and enforcing air pollution levels that cities must meet. These efforts include reducing vehicle emissions, especially from diesel powered vehicles. So under CAA, fleets that own or operate 10 light duty vehicles, trucks weighing 8,500 pounds (lbs.) or less, and heavy commercial vehicles between 8,500 and 26,000 lbs. are being affected.

Refuse fleets are particularly ripe targets for emission-reduction efforts because of the nature of their operations. A two-year study conducted by Inform, a New York-based environmental research firm, found that the approximately 179,000 refuse trucks operating in the United States today consume 1 billion gallons of diesel fuel annually and have the lowest fuel efficiency (2.8 miles per gallon) of any vehicle type. By comparison, transit buses get 2.9 miles per gallon, single-unit heavy-duty trucks get 7 and tractor-trailers get 6.1 miles per gallon.

Also, while heavy-duty diesel-powered vehicles, including refuse trucks, make up only 7 percent of vehicles on the road, Inform says they produce 69 percent of on-road fine particulate pollution and 40 percent of the NOx emissions.

Refuse fleets also are viewed as one of the best “candidates” for switching to alternative fuels because, much like transit buses, collection trucks in urban areas operate on fixed routes from a central location. This creates an ideal setup for a refueling depot, Inform says.

State governments — especially California's — have upped the ante for refuse fleets. In June 2000, for example, the South Coast Air Quality Management District (SCAQMD) in Southern California voted unanimously to require all refuse trucks and transit buses to stop using diesel fuel. This local regulation, Rule 1193, forces all public and private refuse haulers within the agency's jurisdiction — encompassing Los Angeles and several surrounding counties — and own more than 50 refuse trucks to purchase new alternatively fueled vehicles when adding or replacing units as of July 1, 2001.


The easiest “clean fuel” option for most diesel-powered fleets is biodiesel. But “biodiesel” is actually a misnomer, because in its pure form, it contains no diesel. The fuel is made from organic foodstuffs such as soybeans, vegetable oil and animal fat.

The appeal of biodiesel is that it can be used without major engine or fuel system modifications, according to World Energy Inc., a Boston-based biodesiel manufacturer. However, to be considered a true “alternate fuel” in states such as California, vehicles must operate on 100 percent biodiesel or B100. In that form, however, diesel trucks don't work as well. A B20 blend works best, but B20 is not considered an “alternate fuel” because it is 20 percent biodiesel mixed with 80 percent regular diesel.

B20 can reduce particulate matter by 22 percent, carbon monoxide by 20 percent, and hydrocarbon emissions by 30 percent. But B20's “cloud point” of between 3 and 5 degrees Fahrenheit means the fuel could gel and clog fuel filters and fuel lines in cold weather. B20 also increases NOx emissions and aftertreatment systems to reduce these emissions still are being developed.

Almost all the major diesel engine manufacturers allow fleets to use soybean-based B20 in their product without affecting standard warranties. However, that's not true for trucks using B100. Pure biodiesel has been found to degrade some elastomer and natural or butyl rubber components in truck engines, such as fuel hoses and fuel pump gaskets, so maintenance could be affected.

Natural Gas Option

For refuse fleets operating in extreme non-attainment areas that mandate alternative fuel use only — such as Los Angeles — natural gas has become the leading choice despite high costs.

According to Inform's study, approximately 692 refuse trucks use alternative fuels in the United States — less than 1 percent of all refuse trucks. About 90 percent of those alternatively fueled trucks operate natural gas, with about 75 percent using liquefied natural gas (LNG), and the rest running on compressed natural gas (CNG).

More than half of those trucks are owned and operated by Houston-based Waste Management Inc. Its 400 LNG-powered collection trucks are spread out among 13 fleet sites in California and one in Washington, Pa., Inform says.

Inform says on average, a natural gas refuse truck costs an additional $40,000 over the median $170,000 price tag of a conventional diesel-powered version. “Re-powering” a conventional diesel refuse truck to operate on natural gas — replacing the diesel engine and fuel system — costs anywhere from $30,000 to $100,000. If a fleet installs an onsite natural gas fueling depot, it could spend upwards of $300,000, the group says.

Public funds from federal, state and local governments are available, especially in California and New York, to help fleets defray costs. Three years ago, for example, Santa Monica, Calif., received $739,000 in grants to offset the incremental cost of purchasing 36 heavy-duty alternatively fueled vehicles.

Natural gas costs can fluctuate widely by region and season, but fleet operators can realize a fuel cost savings for natural gas compared to diesel, Inform says. For instance, because natural gas can be purchased with long-term supply contracts, larger fleets can be insulated from market fuel price volatility, ensuring more consistent operating costs. Natural gas also is taxed at a lower rate than diesel in many states.

Test Results

At the operational level, multi-year tests conducted by the U.S. Department of Energy (DOE), Washington, D.C., have shown that natural gas-powered refuse trucks cost more to operate than their diesel brethren. Most natural gas engines also have lower horsepower and torque ratings than diesel engines of similar displacement, meaning drivers may feel performance differences.

Waste Management, for example, began using LNG trucks six years ago as part of a project funded by the DOE. The department analyzed data from five LNG powered collection trucks at Waste Management's Washington, Pa., facility over a two-year period and compared the results to data gathered from three diesel-powered vehicles of the same size. The LNG trucks were Mack Trucks MR and LE refuse models equipped with Mack's E7G natural gas engine, rated between 325 and 350 horsepower (hp).

The tests showed that the LNG trucks had 9 percent to 12 percent poorer fuel economy than the diesel trucks, 23 percent higher maintenance costs per engine hour, and 54 percent higher per mile fuel costs. Overall, the LNG trucks cost 80 percent more to operate per mile and 37 percent more to operate per engine hour than the diesel trucks.

However, the project helped Mack, Allentown, Pa., improve its E7G engine, raising the maintenance intervals to 900 hours on post-2000 model year engines compared to the 600 hour interval required for the diesel version, the company says.

DOE conducted a similar project with New York City's Department of Sanitation between 1992 and 1997 using CNG-powered trucks. The study tracked six 25 cubic-yard Model LT 484M refuse collection trucks built by Crane Carrier Corp., Tulsa, Okla., and equipped with a Columbus, Ind.-based Cummins L-10-240G engine. The truck's gross vehicle weight (GVW) topped 70,000 lbs., and its CNG engine provided 240 hp and 750 pounds per foot (lbs.-ft.) of torque. Over the five-year study, each truck accumulated 60,000 miles.

The tests showed that the fuel economy of the CNG trucks was 5 percent to 20 percent lower than the diesel ones. The trucks also had more limited range: The diesel trucks carried 50 gallons of fuel, giving them a range of about 95 miles, while the diesel capacity of CNG trucks was 36 gallons, providing a range of 61 miles.

Maintenance and repair also proved to be more expensive, according to the DOE. “[Maintenance] on the CNG trucks shows that they have been somewhat more expensive to maintain than the diesel trucks,” the department says. “A significant part of this differential cost has been the spark plugs and wires for the CNG trucks.”

Tom Harte, manager of New York City's sanitation department at the time, says, “in terms of regular maintenance [the CNG trucks] have been right alongside the rest. The spark plugs and wires were the parts that really caught us by surprise.” At the beginning of the project, the spark plug wires had to be replaced every six to eight months at a cost of about $125 per wire. But Harte says the department has since improved and doubled wire life in its CNG engines.

Harte says he's pleased with the results. “We've really enjoyed running these trucks on natural gas. Our drivers are satisfied with the horsepower and speed, and the vehicles are quieter and cleaner. There is no diesel engine knock, and there are no [diesel] fumes.”

Down the Road

Despite the cost and performance drawbacks of natural gas, refuse fleets can become self-sufficient in terms of vehicle fuel — which is one of the reasons Waste Management continues to build its LNG fleet.

“Waste Management is looking to use the waste gas given off by its landfills as a feedstock to make the LNG to power its own fleet,” says Juliet Burdelski, director of urban outreach for Inform's Sustainable Transportation Program. “Landfill gas already is used as a power source for factories, but using it to power vehicles is tricky. Eventually, however, they could use it to make their own fuel — and that's one of the most interesting possibilities for refuse fleets at this stage.”

To that end, Waste Management purchased four 40 foot by 60 foot waste gas-to-LNG conversion devices from Norwell, Mass.-based CryoEnergy International last year. Waste Management plans to begin operating that equipment early next year at four California landfills to produce up to 6,200 equivalent gallons per day of LNG per landfill to help fuel the 120 natural gas-powered refuse vehicles it operates in that state.

“Waste Management has been experimenting with a variety of clean fuel technologies for a nearly a decade,” says Chairman and CEO A. Maurice Meyers. “We are committed to using new technologies and developing unique partnerships … to move from pilot projects to the commercial deployment of [more] clean heavy-duty trucks.”

Still, Burdelski says, the main motivating factor behind the adoption of alternatively fueled trucks in the waste industry remains regulatory pressure — and that probably will remain the major growth stimulus.

“Over 90 percent of Waste Management's natural gas trucks operate in California, which has the most stringent tailpipe emission rules,” she says. “Environmental regulations will remain the top reason for acquiring those vehicles for some time to come.”

Clean Diesel Twist

One potentially interesting twist to the role alternative fuels might play in the waste industry concerns the advent of truly “clean diesel” engines and fuels starting in 2007.

With “clean diesel” technology on the horizon, many refuse fleets might wonder why they should switch to an alternative fuel at all. Richard Kolodziej, president of the Washington, D.C.-based Natural Gas Vehicle Coalition, says some waste fleets might not have a choice because of state laws.

“Remember, in all towns covered under California's SCAQMD, refuse trucks are but one group of vehicles that are now mandated to use clean non-petroleum fuels — diesel isn't an option anymore,” he explains.

Then there's the cost issue. The technology needed to meet clean diesel mandates in 2007 doesn't exist commercially yet, so the cost of 2007 diesel engines to the end-user hasn't been calculated. Early estimates by engine maker Caterpillar, Peoria, Ill., predict that the technological needs of 2007 engines could add at least $10,000 to the cost of a heavy truck.

Kolodziej says that, although natural gas engines cost more up-front to buy, grant money is available from both state and federal sources to help fleets defray that cost — an option not available for diesel engines. “California provides a variety of state and local incentives that have helped many fleets break-even on the purchase cost for natural gas vehicles,” he says. “Then over time, they can get ahead on vehicle operating savings.”

So natural gas as a vehicle fuel can be less expensive than diesel in many cases, Kolodziej notes, also pointing out that the low-sulfur diesel fuel needed for 2007 engines will be more expensive than regular diesel, from between 5 to 20 cents per gallon.

“Clean” diesel won't necessarily solve energy dependence issues because it still will be made from oil largely imported from overseas. “However, natural gas is largely domestically produced so it could help us lessen our reliance on oil imports,” Kolodziej says. “I'm not saying we could or should stop using oil tomorrow, but that using alternative fuels where it makes sense and with the proper incentives can lessen the impact oil price increases can have in this country.”

Sean Kilcarr is senior editor for Waste Age's sister publication, Fleet Owner.


One of biggest hurdles natural gas-powered truck engines must overcome is the ability to match the horsepower and torque output of their diesel brethren. San Francisco-based Norcal Waste Systems is testing 14 liquefied natural gas (LNG) powered transfer trucks — Denton, Texas-based Peterbilt 387 Class 8 tractors equipped with Cummins ISX-G engines — to do just that. The engines have been modified by Columbus, Ohio-based Cummins and its Vancouver, Canada-based partner, Westport Innovations, to operate on a blend of 94 percent LNG and 6 percent diesel fuel. The diesel fuel is being used as a “spark plug” to ignite the LNG in the engine's combustion chamber with the most efficiency.

“The trucks equipped with the ISX-G engine allow us the same performance level obtained utilizing diesel,” says Bennie Anselmo, Norcal's fleet manager. Norcal eventually plans to operate 38 transfer trucks with the ISX-G engines, hauling more than 2,200 tons of garbage and recyclables a day to a landfill in Alameda County, Calif., and recycling facilities across the Bay Area, he says.

“We also are looking at the possibility of developing a Westport-type system for the refuse collection fleet, where engines could be converted to run on alternative fuel,” says Mike Sangiacomo, Norcal president and CEO.

Norcal has defrayed the cost of adopting this new engine technology through grants distributed by the Bay Area Air Quality Management District (BAAQMD), based in San Francisco. The group has provided Norcal with $2.2 million in the past four years, both for trucks and to build an LNG refueling facility, says Ellen Garvey, BAAQMD's executive officer.

About the Author(s)

Sean Kilcarr

Senior Editor, Fleet Owner

Sean Kilcarr is the senior editor of Fleet Owner.

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