New York City is testing a group of hybrid garbage trucks, which look much like normal trucks. (New York Department of Sanitation)
NEW YORK -- It sounded like a garbage truck and smelled like one, too. Aside from the giant pastoral scene on its side, it even looked like a standard-issue New York City garbage truck.
But the 36-ton refuse collector that rumbled out of the Department of Sanitation's Central Repair Shop in Queens in November was equipped with a diesel-electric powertrain, one of just a handful of hybrid garbage trucks being tested around the country. This one was built by Mack Trucks, which is part of the Volvo Group.
How it works
- As in the hybrid systems designed for passenger cars, the garbage truck's electric motor serves as a generator when slowing down. This regenerative braking feature captures some of the energy expended when accelerating and uses it to charge a 500-pound lithium ion battery.
- In the Mack's hybrid system, the electric motor cannot drive the truck by itself -- its job is to lower the demand on the diesel engine, which improves fuel economy.
To New Yorkers who saw the big Mack drive by, the truck seemed no different from its all-diesel brethren. It stopped and idled much like a regular garbage truck, and its hopper was capable of crushing and storing up to 13 tons of trash. But with a 120-kilowatt electric motor supplementing its six-cylinder diesel engine, the hybrid accelerated with less effort, the driver said.
Gas mileage is, of course, what made hybrid cars and utility vehicles popular with drivers, who get the greatest benefit from their operation in city travel. This makes hybrid drive systems ideal for garbage trucks, with their start-and-stop routine.
Heavy-duty trucks consume about a third of the nation's vehicle fuel, so the potential savings is significant. According to IBM, a hybrid 18-wheeler can save more fuel than two dozen hybrid cars.
"Without a doubt, hybrid technology dovetails with trucking," says Sanjay Rishi, vice president of IBM's global automotive group, which provides systems software to hybrid manufacturers.
Because the power demand of heavy-duty trucks requires larger, more expensive batteries, the development of affordable trucks is said to be about 10 years behind that of hybrid passenger cars. That has increased the focus on New York City, which is testing four hybrid designs.
In about a year, the sanitation department will have a better feel for which model saves the most fuel, is easiest to maintain and handles the best . Then the city will choose a winner and start buying 300 a year.
The new trucks are expected to reduce fuel consumption by about 30 percent, which means potential savings of millions of dollars once the city adds more hybrids to its fleet. Exhaust emissions are expected to be cut by a similar amount.
Seattle has a small fleet of heavy-duty hybrid trucks, like this boom truck used by Seattle City Light. (Barry Gibbons)
Industry experts say that large orders from New York City will spur the production of other heavy-duty hybrid trucks, which could bring their price down substantially. The city paid about $500,000 for the Mack hybrid, more than double the $225,000 that a diesel-only model costs. Government grants covered the difference.
About 4,850 medium- and heavy-duty hybrid trucks are expected to be on the road by next year, a big jump from just 200 in 2006, according to Calstart, a nonprofit that promotes cleaner vehicles and fuel efficiency. While costs remain high, the economies of scale that would come with large orders -- coupled with government rebates and incentives -- could help persuade profit-driven trash haulers, utilities and bus companies to buy hybrids.
"Hybrid trucks are on the cusp of the market and need a crowbar to push them over the line," says Bill Van Amburg, senior vice president of Calstart. New York's test, he says, will "beat the heck out of these trucks, but we'll really know the fuel use and reliability."
Leave a comment