The Car and Truck Fleet and Leasing Management Magazine

Greenhouse Gas Management for Medium-Duty Fleets

Strategies to increase the fuel efficiency of medium-duty trucks include selecting lower-carbon vehicles, spec’ing for efficiency, engaging drivers in reductions, and tracking greenhouse gas emissions.

September 2010, by Jason Mathers & Karen Healey

Medium-duty trucks, identified as Class 3-6, are the workhorses of the American economy. These vehicles deliver food and beverages to restaurants and convenience stores, drop off packages at homes and offices, serve as mobile workshops for all types of technicians, and perform thousands of other daily tasks. They also use a lot of fuel - more than 8 billion gallons per year. 

This fuel use represents a significant cost for the businesses that use these vehicles to deliver products and services. In addition, the combustion of fuel contributes to global warming.

By increasing truck fuel efficiency, companies can reduce costs and decrease carbon dioxide emissions - the main contributor to human-caused global warming. Medium-duty trucks emit an average of more than 13 metric tons of carbon dioxide per vehicle each year. Focusing on reducing these emissions - including ongoing emissions measurement - needs to be at the core of any comprehensive fleet "greening" effort.

Select Lower-Carbon Vehicles

The most important environmental decision a fleet manager makes is which vehicles to have in the fleet. Relatively minor changes in vehicle selection can result in significant environmental - and financial - benefits over time. Consider the following strategies when choosing fleet vehicles.

➧ Move to Lower GVW Trucks.

Lighter and less-powerful trucks are more fuel efficient. A company can reduce fuel use significantly by "right-sizing" its fleet - selecting trucks no larger or more powerful than necessary for the application. Avoid the common pitfalls of spec'ing the entire fleet based on a "greatest power demand" scenario, when such a scenario can be served with a few larger vehicles. Within the same gross vehicle weight class, it may be possible to choose a more efficient engine that can do the job at hand. (See Table 1).

➧ Consider High-Efficiency advanced technology vehicles.

Hybrid-electric vehicles, hydraulic hybrids, and electric vehicles all have the potential to increase the fuel efficiency of trucks and reduce emissions. Fuel-efficiency improvements between 15-50 percent are likely from these advanced technology engines. These vehicles are particularly well-suited for urban pickup and delivery and other short-haul markets. They are also a good fit for fleets with auxiliary power needs, such as utility trucks, which can draw power from the electric battery to run onboard equipment, eliminating idling and further increasing fuel savings.

The first commercially available medium-duty hybrid trucks hit the road in 2005 through a partnership between FedEx and Environmental Defense Fund (EDF). Today, more than 115 fleets contain medium- to-heavy-duty hybrid vehicles. Nearly 2,000 of these cleaner vehicles are on the road, available in more than 35 models and in every truck class. The performance and maintenance records of these vehicles are strong.

The most significant barrier to further expanding the market for these vehicles remains the upfront cost. Hybrid trucks typically cost between $23,000-$45,000 more than traditional trucks, but price differs between applications and models, while bulk purchases can help push the price toward the lower end of the spectrum. Still, for many applications, the trucks' payback is beyond the time limit of most companies.

To support the use of hybrid vehicles, the U.S. federal government and many states have funding available to help fleets purchase cleaner and more fuel-efficient vehicles. Grants, rebates, and tax credits can help bring down the incremental costs of advanced technologies and make the business case for cleaner trucks. Under the most generous of these programs, fleets can achieve a 2.5-year return on investment (ROI) from a hybrid truck.

Incentives may impact financing arrangements and as a result, the total financial benefits of the incentives need to be evaluated. Further, incentive programs can be complicated to navigate because their benefit may depend on a particular fleet's specific situation. However, the payoffs can be significant, so it is worthwhile for a fleet to do its homework and investigate these programs.

➧ Explore Lower-Carbon Fuels.

Not all fuels are created equal in terms of greenhouse gas (GHG) emissions. Diesel, gasoline, and other fuels all emit different amounts of carbon. Data on the carbon content of fuels is available from the U.S. EPA on a volume basis. For example, per gallon, gasoline emits more than 19 lbs. of carbon dioxide and diesel emits more than 22 lbs. Of course, other variables must be taken into account as well, such as the energy content of the fuel and engine efficiency. Consider that due to its higher energy content and more efficient combustion process, a diesel vehicle can travel about 30 percent farther on a gallon of fuel than a comparable gasoline model.

All fuels have emissions associated with their creation that aren't factored into EPA's tailpipe numbers. There are some fuels that have a lower GHG emissions profile when combusting the fuel, but this benefit is reduced or eliminated by an energy-intensive manufacturing process. Fleets seeking to reduce GHG footprints should do due diligence to ensure their fuel choices don't simply push emissions up the production chain.

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