ENVIROWATCH

Let’s face it: medium- and heavy-duty trucks haven’t always been the “greenest” or most fuel-efficient vehicles on the block. But times have changed, and with the addition of a hybrid truck, your fleet’s operating costs can reflect this now and in the future.

“Fleet owners and operators are concerned about all expenses at this time. And even though fuel costs are relatively low right now, they are expected to go up again significantly,” says Richard Parish, senior program manager, CalStart, a member-supported organization serving to expand the high-tech clean transportation industry, and creators of the Hybrid Truck Users Forum. “We want fleet owners to be prepared.”

Hybrid trucks can help by reducing fuel costs, running quieter, emitting fewer emissions and promoting an overall green image. As an added bonus, tax incentives abound for heavy hybrids (see chart on page 45), and some states even offer their own special incentives. For example, the California Air Resources Board approved $42 million in Air Quality Improvement Program projects under AB118 – including $25 million in funding available for public or private fleets that purchase hybrid trucks.

Inner workings
Parish suggests fleet owners first become familiar with hybrid technology and then consider the many options on the market today.

While hybrid configurations vary slightly depending on manufacturer, a typical system for a medium-duty truck includes an electric generator/motor, a lithium ion battery pack and a diesel engine.

Today’s diesel engines must provide a certain amount of horsepower and torque to muscle through various jobs, but the addition of a hybrid system allows for a downsized engine that does basically the same amount of work.

“The hybrid system’s electric motor provides a supplemental boost of power to launch the vehicle, so the driver can pull his foot off the brake and run the vehicle off that extra horsepower and the battery,” explains Ken Marko, market planning manager, Peterbilt.

The vehicle’s battery recharges once the driver releases the throttle and barely uses the brake (termed regenerative braking) to bring the truck to a complete stop. Electricity derived from regenerative braking then stores in the battery, later assisting the diesel engine for acceleration. This entire process saves fuel and reduces brake wear.

When driving, hybrid operators should attempt to conserve momentum. “Hard acceleration and hard braking waste energy, while light acceleration and braking will use less fuel,” explains David Bryant, vocational sales manager, hybrids, Freightliner trucks. “Looking ahead while driving to maintain moderate speed will also conserve fuel.”

Because stopping recharges the vehicle, hybrid trucks prove especially useful for utility or pick up and delivery applications. But for long haul applications, drivers won’t be able to recharge the battery as much, since the truck essentially runs more than it stops.

Regardless of application, drivers receive benefits of supplemental torque from the hybrid system until the battery depletes. Once it depletes, the truck automatically restarts and recharges the battery off the alternator, allowing continued use of the truck’s crane or bucket. Recharging should take less than five minutes.

Many hybrid trucks also feature an electric PTO operating off the hybrid battery or electric motor, so you can simply shut the truck off, rather than idling, and use the EPTO to power tools on the jobsite. “Using the EPTO function for stationary applications can reduce engine on-time four to five hours per day in some applications,” Bryant says. “That reduces fuel consumption up to 60 percent and extends the useful life of the diesel engine.”

Hybrid batteries are designed to last the life of the vehicle, but realistically Marko says they will most likely need to be replaced every seven to eight years on a medium- to heavy-duty truck. And although fairly expensive right now, the price of the batteries is expected to decrease as hybrids become more mainstream.

Cost benefits
Still, maintenance associated with hybrids contributes to a relatively low operating cost. “Other than checking the transmission oil level and extended life coolant level (for the hybrid’s cooling system), Eaton recommends a filter change for the hybrid batteries, since they’re air cooled, about every four to six months,” says Josh Lepage, sales manager product integration, International. Filter servicing should cost $15 to $20, and a service technician who has been properly trained can do this with no problems.

Compare that to an automatic transmission, where the filter and oil need to be changed every 18,000 miles, and your expenses come to around $500 to $700 every service interval, Lepage says.

Although ROI will differ somewhat across the board, the experts we interviewed estimate hybrid owners should begin to see a return within five to eight years. Of course, this depends on several factors, including the truck application, miles driven or hours used, price of fuel and grant or tax incentives received.

The Hybrid Truck Users Forum, or HTUF, has an example (see page 42) of the life cycle cost analysis of a utility bucket truck when comparing a hybrid to a conventional truck.
Once calculated, HTUF’s cost analysis model shows the present value of the conventional vehicle cost over a 10-year period equals $227,574, while the hybrid vehicle cost for the same amount of time equals $201,055 – or a benefit of $26,519.

Pushing ahead
Truck manufacturers have initially focused on supplying medium-duty hybrid trucks for utility, refuse and pick up and delivery applications, working to integrate hybrid components to minimize the impact to upfitters and customers. “We have customers using hybrids to service and repair bridges, collect recycled materials, work on rail lines and of course, work on power lines and trim trees,” Bryant says.

As for the future, manufacturers say they see potential for hybrid technology in heavy-duty truck applications, including construction. But this challenge comes at no easy cost. “While the hybrid technology available today may be acceptable for medium-duty applications, it won’t suit an 80,000-pound heavy-duty truck – the power and performance simply isn’t there yet,” says John Walsh, public relations manager, Mack Trucks. Mack first intends to develop refuse hybrids, before focusing on Class 8 hybrid truck offerings.

Other manufacturers, however, plan to bring Class 8 hybrid technology to market within the next several years. International has announced a working partnership with Arvin Meritor and plans to introduce a Class 8 hybrid around 2011 or 2012. So far, Peterbilt looks to be closest to production, with an expected 2010 release of their Class 8 Model 386 Hybrid.