Kenworth Hybrid: This Blue Truck Is Really Green

If you can't pass the higher costs on in surcharges, it's time to reduce fuel usage. And hybrid-drive trucks are capable of some serious savings.

February 2008, - Test Drives

by Tom Berg, Senior Contributing Editor - Also by this author

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The UltraShift is the only transmission offered with Eaton's hybrid system. However, a couple of Kenworth T300s with Azure Dynamics hybrid systems are running with Allisons, delivering meat products in Brooklyn, N.Y. Azure retrofitted its components into the trucks and Kenworth was not involved in the project. Allison was, though, and I got to drive one of those trucks during a demonstration last summer in Speedway, Ind., near Indianapolis. The drive on Allison's testing complex was short and on level pavement, except for a steep test hill. But like Eaton's hybrid drive, the Azure system allowed the truck to move out on all-electric propulsion, then switch to diesel as road speed and the demand for horsepower rose.

Electric launch occurred a few times with the Dunn truck, and regeneration happened often because downhill sections required frequent braking. That's when the motor on the driveline becomes a generator, sending current to the lithium-ion batteries in a box along a frame rail. You can feel the drag when you take your foot off the accelerator and, if that's not enough braking force for a situation, touch the brake pedal. The engine also had a Jake Brake that provided more retarding power, and we used it while we drifted down a long hill toward the end of our jaunt.

A liquid crystal display hung on the dash showed what was happening in the system - engine power, hybrid power, or braking regeneration. It also showed the extent of charge in the batteries. The LCD was a little hard to read; production trucks will get a color display that's larger and brighter. Next to the LCD was a Garmin 7200 GPS navigation system, which Geyer has installed on most of the Dunn trucks. We didn't use it this day, but on regular runs it helps drivers find new addresses and saves "huge amounts of time," he said.

OK, back to business. Aside from purchasing cost, a hybrid-drive system adds complexity to a truck, and we all know that this inevitably leads to expense. How much is still unknown because only a few hundred diesel-electric hybrids are now at work. FedEx, which operates 94 vans with pretty much the same system, says problems twice grounded the entire hybrid fleet, but Eaton (which historically has been good at supporting its new products) fixed everything, and now the trucks are averaging 94 percent availability.

Geyer reports that after half a year of running, he's had no problems with the Kenworth hybrid. If he had, they'd be covered, at least in part, by Eaton's 3-year/150,000-mile warranty on the hybrid components. Those two lithium-ion batteries will eventually go sour, and will be much more expensive to replace than common lead-acid types (though they should cost less by the time that's necessary). But it's likely that he could buy a set with just one year's fuel savings. As component prices start falling, the truck's green sheen should get brighter.

Business Case Still Tough To Make

Dunn Lumber was focused on the environment when it bought the T300 hybrid with its $20K price premium, and didn't try to make a business case for it. There really isn't one, mostly because the truck doesn't run enough miles - only 12,000 a year - to capitalize on its fuel efficiency. Tax credits of $4,500 to $12,000 for a heavy hybrid (which in federal terms is a truck or bus weighing over 8,500 pounds) help some buyers, but not in this case.

Here's some math based on fuel savings alone: Geyer says the hybrid's been getting 6.85 mpg in its urban delivery duties, so it will consume 1,751.82 gallons over 12,000 miles. Other 32,000-pound-GVW trucks in the fleet get 5.03 mpg, so each burns 2,385.69 gallons a year. Multiply each of those gallon numbers by $3.25, which is about what Dunn has been paying for fuel, and we see that the bill to feed the hybrid will be $5,693.43 compared to $7,753.50 for a straight diesel truck.

Thus annual fuel savings are $2,060.06 - a nice piece of change, but at that rate it'll take 10 years to pay off the $20,000 upcharge for the hybrid system. If it ran 24,000 miles a year, the payback would come in five years, and at 50,000 miles annually its premium would be recovered in two and a half years. Rising fuel prices would also reduce the payback time.

Now let's factor in a $12,000 tax credit allowed by the Internal Revenue Service. That would cut the hybrid's extra cost to $8,000 and the payback time to four years. But Dunn can't get the credit because its Kenworth-Eaton hybrid is not on the IRS' list of certified vehicles. Certain walk-in vans assembled by Freightliner Custom Chassis, and utility and P&D trucks made by International, all using Eaton hybrid systems, as well as certain automobile hybrids and alternative-fuel cars and trucks, are on the list (at,,id=175456,00.html). Kenworth says it's working to get its hybrid certified.

By the way, the $20,000 premium paid by Dunn is 37.5 percent of the T300's chassis price of about $75,000. That's not bad, as fleets running prototype and pre-production hybrids say they paid 50 to 100 percent more than for straight diesel trucks. Their components - especially the lithium-ion batteries - are expensive due to their low production volume, manufacturers explain.

However, Eaton has announced that it's putting its hybrid system into regular production, and will buy more components from its suppliers. Kenworth, Peterbilt, Freightliner and International say they will begin assembling hybrids as part of regular production in March. Regular production should lower prices, which in turn will tempt more orders, which will bring on more volume, and so on. Eventually the business case should begin to shine, with or without tax credits.

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