Soaring gas prices and emissions regulations have industry groups and fleets putting a tremendous effort into finding a replacement for diesel fuel and gasoline. Unfortunately, most of the alternatives are not cost-effective. But some alternative fuels are getting closer.
Only about 1 million vehicles use alternative fuel, less than 1 percent of the 200 million light, medium and heavy duty vehicles in operation. Most industry veterans believe this is because alternative-fueled vehicles cost more, weigh more, have a smaller range and fewer opportunities to refuel, require training and must be fueled twice because they require two different fuels. Fueling facilities also cost more.
These disadvantages are not quite offset by the lower cost of fuel and decreased maintenance requirements. Price spikes, regulation changes and operational problems also are constant threats. But advocates say the reduction in harmful emissions is priceless.
Nevertheless, the list of alternative fuels that could replace diesel for heavy duty commercial vehicles keeps growing — and now includes natural gas — compressed [CNG] or liquefied [LNG] — methanol, denatured ethanol, liquefied petroleum gas (LPG), hydrogen, biodiesel, coal-derived liquid fuels and electricity. All have advantages and drawbacks.
Marrying Natural and Diesel
Alternative fuels increasingly are being used in conjunction with current fuels. For example, Caterpillar (Cat), Peoria, Ill., has announced a dual-fuel engine that runs primarily on natural gas — up to 85 percent in most applications — with a small volume of diesel injected to provide ignition. The engine can run on LNG or CNG, both of which have high octane for better performance.
Besides reducing emissions, other benefits of this combination include the use of exhaust and compression brakes, and easy conversion back to straight diesel for improved resale value. Also, if a failure occurs in the natural gas system, the electronic controls revert the engine to its traditional diesel operation.
Taormina Industries, a California subsidiary of Fort Lauderdale, Fla.-based Republic Services, is using 36 dual-fuel engines in its roll-off, front loader and transfer refuse truck fleet.
“The dual-fuel engines definitely are meeting expectations,” says Tom Vogt, president of Taormina. “We ordered 13 additional engines.”
Other companies report that these engines have not affected tare weights, provide decent horsepower (hp) and save fuel.
The Cat C-12, 410 hp dual-fuel engines primarily use LNG, but need diesel to provide the spark to ignite the gas. The engine pulls in air and injects natural gas into it, with enough diesel for ignition.
At idle, the engine burns 100 percent diesel because it is tough to operate a natural gas engine at its low-compression ratios. As engine power is built up, more natural gas is added.
According to Harris Ranch, LNG was selected because it is easier to store and handle, and is quicker to refill than CNG. LNG also keeps the vehicle's gross vehicle weight down. The company reports it only takes 1.7 gallons of LNG vs. 3.5 times as much CNG to equal the driving distance of 1 gallon of diesel.
Natural Gas Put to the Test
LNG also is being tested by waste haulers. Through a partnership with an electricity supplier, the industry's largest refuse hauler, Waste Management Inc., Houston, has found a cost-effective way to convert trucks to natural gas fuel.
San Diego-area utility Pacific Gas & Electric (PG&E) Corp. is underwriting the cost of converting 90 percent of Waste Management's fleet in San Diego County to LNG vehicles over the next 18 months. In return, PG&E Corp. will receive the emissions credits required to build a much-needed electric power generating station in the area.
PG&E has agreed to pay Waste Management the difference between replacing 120 of its trucks with updated diesel-fueled engines and replacing them with LNG-fueled trucks.
The conversion is expected to reduce nitrogen oxide (NOx) emissions in the area by more than 35 tons a year, which is one-third of the NOx offsets required for the new generating plant.
Mack Trucks, Allentown, Pa., will supply the 120 new trucks, which will be powered by 12-liter Mack E7G Eco-Tech spark-ignited engines. The trucks will have two LNG cryogenic tanks to keep the fuel at low temperatures. Each vehicle will carry 150 gallons.
Alan Walsh, district manager for Waste Management in San Diego, says the fleet's diesel trucks currently consume approximately 50 gallons a day. LNG-powered units are expected to consume about twice that, requiring more fuel capacity. Mack says the LNG conversion adds around $40,000 to the vehicle cost.
PG&E also is helping to pay for a new LNG fueling facility to be built at Waste Management's El Cajon terminal. The new facility is expected to cost $1.5 million to $2 million and will be completed in six months.
In Nov. 2000, Cummins Engine Co., Columbus, Ind., announced a new 280-hp rating for its C8.3-280G natural gas engine. The engine has a peak torque of 850 pounds-foot (lbs-ft) at 1,400 revolutions per minute (rpm) and a governed speed of 2,400 rpm.
While some car manufacturers are de-emphasizing their electric car projects, commercial vehicle users are forging ahead.
For example, after a one-year test, the U.S. Postal Service, Washington, D.C., ordered 20 electric parcel delivery vans from Solectria Corp., Wilmington, Mass., for use in New York City. Delivery is expected in August. The Postal Service also signed a contract for 500 battery-powered postal vans.
Additionally, one bottled water company is evaluating an electric route truck. McKesson Water Products Co., Pasadena, Calif., has about 2,000 vehicles, of which about 1,200 are medium duty route trucks. About half are diesel and half are propane-powered vehicles.
Propane is cleaner burning — 60 percent cleaner than diesel and 30 percent cleaner than gasoline. And McKesson is considering an electric or hybrid-electric vehicle, as another alternative.
The company took the electric bus concept and adapted it as a “built for purpose” water delivery route truck. Building the truck from the ground up for electric power cost the same as a standard propane-powered route truck, a spokesman says.
The truck measures 29 feet long and 8 feet wide, and weighs 29,000 pounds. It has a Thundervolt, San Diego, drive-train; contains a drive motor that is 250 kilowatts (KW) (335 hp) and 205 KW (275 hp); gearing that is 4.4-to-1 planetary reduction; regenerative brakes; and 112 sealed maintenance-free lead-acid batteries. The electric vehicle has a 10,000-lb load capacity.
The unit accelerates from 0 to 30 miles per hour (mph) in 15 seconds, and 0 to 60 mph in 50 seconds, McKesson says. Maximum speed is 75 mph, with a maximum starting grade of 25 percent. There is no smoke or odors, near silent operation and zero emissions at any speed because in traffic or at a stoplight, the engine does not run.
The truck has accumulated about 20,000 route miles since July 1998. McKesson calculates the current truck range at 70 miles, but on one test it ran 85 miles on a single charge. Charging takes 2 hours from no charge to 80 percent, and 4 hours to a full charge. The vehicle returns every night to its charging station.
The electric-powered truck also has regenerative braking — if a driver holds his foot on the brake, the brakes turn into a generator and regenerate the batteries by charging them.
The best application is on a fairly short mileage, stop-and-go route on fairly flat terrain, McKesson says. Once the driver touches the accelerator, an electric charge goes to the battery. There is zero fuel loss due to idling or stopping in traffic.
The calculated 7 miles per gallon (mpg) the truck gets is better than the mileage of a conventional vehicle that burns fuel while idling, the company says. The vehicle's fuel savings potential is approximately 25 percent over diesel.
A Hybrid Electric System
In addition to electric trucks, Volvo Trucks North America Inc., Greensboro, N.C., is building a Class 8 tractor powered by a hybrid electric propulsion system for a U.S. Army program.
This hybrid truck will be propelled at low speeds by electric motors and run at high speeds by a diesel engine. The propulsion system combines a 460-hp diesel engine with two 250-hp electric motors. Lead acid batteries, charged by an on-board generator, will power the electric motors.
Volvo says the combination of the two technologies could significantly reduce emissions while increasing fuel efficiency — without sacrificing performance. The hybrid also allows for shift-free acceleration.
In theory, the diesel-electric combination could give drivers more power than today's engines, Volvo says. The company expects the system to cut operational costs due to greater fuel efficiency and less engine maintenance.
The tractor also will be equipped with advanced safety systems. Electric motors, for example, will be used as an auxiliary retarder. During brake applications, the motor's magnetic field will be reversed to provide increased stopping ability. The auxiliary retarding effect of the electric motors also will be used to recharge the batteries. And Volvo projects the auxiliary retarding effect of the electric motor will double brake life.
Cleaning Up Diesel
The first vehicle with a diesel hybrid electric drive system was delivered in Dec. 2000. The hybrid-electric powertrain was developed by Allison, Indianapolis, and is hooked to a modified Cummins ISB-270 with catalyzed soot filter. This combination will increase fuel economy and reduce emissions, the company says.
This is good news for the waste industry because diesel fuel with lower amounts of sulfur may be necessary to meet Environmental Protection Agency (EPA), Washington, D.C., requirements. In Dec. 2000, the EPA mandated a reduction in the sulfur content of highway diesel fuel from 500 parts per million (ppm) to 15 ppm by 2006.
Opponents say the rule is based on aftermarket technology and controls that have not been proven, and fuel suppliers say they cannot produce an adequate supply until the sulfur limit for the off-road market is known.
But Cat already has announced a 3126B “Clean Diesel Power” engine that reduces NOx and non-methane hydrocarbon (NMHC) emissions by 13 percent over today's typical engine, according to the company. And recently, Cat said it further reduced these emissions by up to 22 percent. The 175 hp to 330 hp-engine operates on conventional diesel blends, or ultra clean and low sulfur fuels.
Government Kicks In
To further the use of clean-diesel trucks, the Department of Energy, Washington, D.C., is providing $1.6 million to fund four clean-diesel research and development projects. They include:
A turbo-motor generator project by International Truck and Engine Corp., Chicago, Honeywell, Morristown, N.J., and Turbodyne, Carpenteria, Calif., to increase transient torque and acceleration, and reduce turbolag and black smoke emissions;
A waste heat recovery turbo-compounding project by Caterpillar that uses a second turbocharger to convert heat energy to generate electricity;
An electronic optimization of nonthermal plasma for NOx reduction by Mack and John Deere, Moline, Ill.; and
A project using thermoelectrics and bulk semiconductors on exhaust systems to convert waste heat to electricity for on-board use.
It's unclear whether clean diesel, an electric or hybrid electric system, or some form of natural gas will win the alternative fuel race, but one thing is certain: Tomorrow's waste industry is sure to use vehicles that will have far fewer emissions that will be far better for the environment.
Bob Deierlein is Waste Age's truck editor.