Roush CleanTech’s changes to make a standard Ford F-250 run on propane include a 62-gallon fuel tank in the bed, stainless-steel fuel lines, aluminum fuel rails and related hardware.

A Clean Fight

While diesel may be today’s fuel of choice, it faces growing competition from several alternative options

In commercial trucking, diesel is the undisputed heavyweight champion of fuels. Diesel packs an impressive amount of energy, supporting engines with the powerful punch of low-end torque – ideal when traveling long distances and hauling heavy loads. But despite engine upgrades and aftertreatment devices that reduce smog-producing NOx and lung-clogging particulate matter, diesel-powered trucks still leave a sizable carbon footprint.

A growing number of fleets – facing greenhouse gas accountability, soaring diesel costs and a call to cut ties with foreign oil – are exploring their alternatives.

While propane has made its biggest impact in light-duty vehicles, it now is fueling everything from street sweepers to school buses.

Freightliner announced that its Cascadia 113-inch BBC daycab soon will be available with natural gas technology using the Cummins ISX12 G engine.

Options like compressed natural gas (CNG), liquefied natural gas (LNG), liquefied petroleum gas (LPG or “propane autogas”), electric power and hydraulic accumulators all are enjoying added attention, particularly among environmentally sensitive fleets. The 18 fleets that belong to the Energy Department’s National Clean Fleets Partnership account for 12 percent of the commercial vehicles on American roads, and they all have embraced a mandate to use less gasoline and diesel.

Some of the partnership’s latest members include Best Buy, Johnson Controls and Veolia Environmental Services’ solid waste division, which boasts four of its own CNG fueling stations and more than 100 CNG vehicles.

But alternative fuels tend to store less energy per volume than diesel or gasoline, so their related trucks need larger fuel tanks or have to fuel up more often, and equipment upgrades also add to purchase costs. That’s why a fleet considering a switch to an alternative power supply of any sort needs to take a close look at its unique operating needs.

Natural gas

Natural gas costs 30 percent less than diesel when comparing diesel equivalent gallons (volumes of fuel that store the same energy), but the LNG truck itself can cost 50 percent more than its diesel counterpart, largely because of the need for specialized fuel tanks. Calculated savings over a truck’s life will depend on the number of miles traveled. (See “Ready for heavy-duty,” page 60.)

“Thirty-five years ago, diesel was the alternative.”

– Todd Mouw, vice president of sales and marketing, Roush CleanTech

Natural gas supports fleets that want to embrace domestic energy sources. President Obama described the United States as the “Saudi Arabia” of natural gas. Available supplies also are expanding because of hydraulic fracturing techniques that are tapping into pockets of the fuel trapped in layers of shale.