WASHINGTON—The next big thing in hybrid vehicles could be a garbage truck.
A combination of fuel cost pressure, pollution problems and promising technology is drawing virtually all the U.S. trucking industry's leading makers and fleet owners to hybrid trucks. The trucks, which convert braking energy into supplementary power, aren't in mass production yet, but that's almost entirely a pricing issue.
In the case of hybrid garbage trucks, New York, Chicago, Houston and other big cities want them. Truck makers Peterbilt and Oshkosh are keen to build them. And the Environmental Protection Agency is promoting them as ideal platforms for hybrid technologies that work best on vehicles that stop and go a lot.
Garbage trucks are without peer in that department, according to Matt Stewart, a vehicle purchasing analyst for in the city of Chicago who specializes in exploring green options. "You pull up, you idle, you stop, you load. You pull up and do it all over again." It adds up to 300 to 1,200 stops a day per vehicle. For a conventional diesel, 4 miles a gallon is decent mileage.
Most other hybrid trucks in the prototype and field-test stages do similar stop-and-go work. Delivery vans, for example, and shuttle buses are approaching production, according to Bill Van Amburg, the senior vice president of WestStart-CALSTART. The nonprofit group, based in Pasadena, Calif., brings together hybrid truck makers and potential customers.
"We're not yet at the tipping point, but we're making strong progress," Van Amburg said.
With foreign competitors focused on high-efficiency diesel engines, "North American hybrid truck technology right now is world-leading," he said.
Fleet owners that are testing hybrid trucks include the Postal Service, which operates 142,000 vehicles, and the two biggest private fleets: UPS (91,000 vehicles) and FedEx (70,000). Companies that do lots of commercial deliveries, such as Coca-Cola, also are testing hybrids. So is the Defense Department.
Public utilities are testing hybrids, too. Like the Pentagon, utilities want hybrids that can deliver electrical power with their conventional diesel engines off. Among those that are testing hybrids are Florida Power and Light, Duke Energy, Georgia Power, TXU Electric Delivery, Pacific Gas and Electric, Southern California Edison and the Sacramento Municipal Utility District.
According to George Survant, the vehicle fleet manager for Florida Power and Light, his company's hybrid "trouble trucks" cut fuel use by 40 percent to 60 percent.
While hybrids clearly improve fuel efficiency, reliability and maintainability still are being tested.
At the FedEx Express division, hybrid diesel-electric delivery trucks were ready to roll when needed 99 percent of the time during the first 466,000 miles of testing. That's outstanding reliability for prototypes. The trucks cut the soot released into the air by 96 percent and nitrogen oxide pollution by 65 percent compared with diesel counterparts. They also improved fuel efficiency by 57 percent, according to FedEx spokesman Ryan Furby.
Drawing more attention lately is a new hybrid technology that excites many garbage truck operators. It converts the energy produced by braking into hydraulic power. Toyota's Prius and other popular hybrids turn that energy into electricity.
Instead of a bank of storage batteries, hybrid hydraulic trucks carry a pair of tanks the size of small water heaters. They're bolted to the truck's chassis and connected to its drive shaft and each other by a device that can function either as a pump or a motor.
One tank is a reservoir for hydraulic fluid. The second tank contains nitrogen gas. Energy that's produced when the truck brakes is used to pump the hydraulic fluid from the reservoir into the second tank. As the second tank fills with the fluid, the gas is compressed, storing the energy produced by braking. When the truck next accelerates, the compressed gas pushes the hydraulic fluid back to the reservoir. The force of the fluid's release helps turn the vehicle's drive shaft. In effect, the system is a supplementary motor.
The system, developed by the EPA's National Vehicle and Fuel Emissions Laboratory in Ann Arbor, Mich., and produced by Eaton Corp. of Cleveland, has two advantages:
_ By the EPA's calculations, hybrid hydraulic systems capture up to 75 percent of braking energy. Hybrid electric systems capture about 25 percent.
_ Although hydraulic hybrids offer little to long-haul or high-speed trucking, their ability to kick in a sudden surge in power during acceleration is magical for trucks on severe stop-and-go duty.
So what's in hybrids' way?
Mainly, two linked factors: uncertainty about pricing hybrid trucks and how many to make. Prototypes, which are custom-made, offer only vague clues to price. And price and profitability depend on sales volume
As Bradley Bohlmann, an Eaton vice president for new products, put it: "There are some big, big bets that need to be made."
One possible bettor is Stewart, Chicago's vehicle purchasing analyst, who loves the projected 3,300 gallon-a-year diesel fuel savings for the city's fleet of 500 garbage trucks. He loves the emissions reductions. But until the hybrid's cost is within $16,000 of the $160,000 sticker price on a new conventional garbage truck, Stewart won't buy many, because the fuel savings over the hybrid's expected lifespan won't offset its higher cost.
Hybrids reduce maintenance costs, especially on brake systems, according to proponents and some early users, but by how much isn't clear.
Hybrid trucks seemed to get a major boost from Washington under the Energy Policy Act of 2005, which offers tax credits of up to $12,000 per hybrid truck to compensate for their higher price. The incentive was to start in January 2006, but hybrid makers and potential customers still can't count on it.
That's because the size of the tax credit, which the Internal Revenue Service oversees, depends on how much fuel a hybrid truck saves, and the EPA hasn't come out with a system to measure the fuel savings.
EPA spokesman John Millett referred the matter to the IRS.
"We are working on guidance," IRS spokesman Rob Marvin said.
The impasse disappoints Jim Williams, the director of new product sales for International Truck and Engine Corp. of Warrenville, Ill., which is working with Eaton to build hybrids.
Asked how many he expects to sell this year, Williams replied with the salesman's creed: "As many as I can."
For more information on hybrid trucks, the best place to start is the Hybrid Truck Users Forum at www.calstart.org/programs/htuf