"We'll certainly be able to offer more powertrains, not only standard diesel powertrains, but, we think, hybrid - when we start production - will increase our total volumes," said Emile Charest, manager of engine product development for Volvo Powertrain North America.
"It's going to start small, like anything else. Like the Toyota Prius, at first, it didn't sell too much, but now, people are paying a premium because they want them," Charest said last week.
Trucking companies will be cautious, careful of seeing economic benefit and product quality, so initially, "people in the truck world will try a few. So it's going to be slow growth, not a rapid flash of growth, (but) probably good growth," he said.
The plant, which employs 1,278 people making engines and transmissions for Mack and Volvo trucks, has been a key economic driver in the local economy since Mack moved to Hagerstown in 1961.
Now, hybrid - a combination of electric and diesel power - looms as the next all-important fuel-saving, pollution-reducing technology as truckers grapple with rapidly rising diesel prices and ever-tightening pollution standards the world over.
Picture the usual garbage truck. Its quick, frequent stop/start movements - 1,200 stops per day is not unusual - are a good way to begin understanding hybrid and its potential.
The movements, as the driver tries to cover his territory quickly, are a big energy waster. Diesel fuel is used to propel the truck forward, and then, much of that built-up energy is lost as he brakes to a halt.
"But if you could recapture that, we think we could reduce the (diesel) fuel consumption up to 33 percent" on a refuse or a dump truck, Charest said. "The fuel economy in miles per gallon could be increased 30 (percent) to 50 percent."
A hybrid offers that potential.
An electric motor, coupled to a diesel engine, can convert that lost energy to electricity and, in the process, help slow the vehicle. In addition, when the recaptured energy is stored, it can be used later - instead of diesel fuel - to help the truck speed up.
An electric motor also is better - and quieter - than a diesel engine at propelling a fully loaded 66,000-pound refuse truck forward the first several feet, Charest said. But the diesel is better at powering the vehicle through, so a hybrid uses the advantages of both, he said.
"When you launch that vehicle, it sets you back in the seat," said Charest, who has driven one of Mack's hybrid test vehicles. "When you use that electric motor, it takes off. And, some seconds later, the diesel kicks in.
"It's exciting technology. And it's fun to work on."
Volvo's focus "nearer term is the stop/start market and longer term is the long-haul" trucking market, said Anthony Greszler, vice president of advanced engineering.
For one reason, the development of long-haul hybrid trucks isn't as far along as for the stop/start market, Greszler said. For another, long-haul trucks don't use brakes nearly as often, so the energy that could be recaptured on each truck isn't as great, he said.
But to reduce overall U.S. dependence on diesel and gasoline use, fuel savings in long-haul trucks would help most because there are so many such trucks, according to a Volvo report.
One discovery that really would benefit a long-haul truck more than a stop/start truck is the use of the electric motor in a hybrid system to power equipment that isn't needed all the time, Greszler said.
This would include such equipment as power steering, fans, air conditioning and the air compressor.
The compressor, for instance, is used to operate the brakes. Right now, on a diesel engine truck, the compressor is running, using more fuel, whenever the engine is running, Greszler said.
"Whereas if we only spun it when we actually need compressed air, then we could save all that energy," he said.
In the same way, there are savings in using an electric motor to power the air conditioning and heating units in the truck cab, instead of idling the diesel engine for several hours while the driver sleeps, Greszler said.