TORONTO, Ont. – There’s no question that diesel has been the trucking industry’s fuel of choice for decades, and few challengers threaten to knock it off its well-earned pedestal in the immediate future. Still, in the face of climbing fuel prices and the ever-present drive for lower vehicle emissions, a growing number of medium-duty truck fleets are experimenting with alternatives.

FedEx, for example, has announced plans to introduce hybrid electric delivery trucks in its fleet, noting that the new designs will burn less fuel while offering similar performance and costing the same as a standard medium-duty W700 delivery truck over the lifetime of the vehicle.

With 10,000 of the trucks, the courier giant says it could emit 2,000 tons less nitrogen oxide (NOx), 60,000 lb. less soot and 75,000 tons less carbon dioxide.

From a business perspective, it would use 24.6 million fewer litres of diesel – a 50 per cent improvement in fuel efficiency.

Twenty of the first trucks to be built on a Freightliner chassis, using hybrid electric technology from Eaton, are being purchased this year, and the first two have been rolled out in Sacramento, Calif. By next year, an array of the trucks is planned for use in routes throughout North America.

Hybrid vehicles combine multiple sources of power, and have already emerged in automotive models such as the Honda Insight and Toyota Prius. The parallel systems, such as the one used by FedEx, actually combine the power of an internal combustion engine and an electric motor. Their series counterparts use the engines to power a generator, either charging batteries or turning transmissions.

Combined with the power of the electric motor, FedEx will be able to reduce the size of its typical engine to four cylinders from the current six.

Granted, this doesn’t mark the industry’s first foray into alternative fuels, as medium-duty fleets running in many urban areas appear to be the most eager participants in tests. Their shorter operating ranges simply offer more opportunities to fill up at a limited number of sources of the alternative fuels.

UPS, which already operates more than 1,000 compressed natural gas vehicles in the U.S., and 800 propane-powered vehicles in Canada and in Mexico, is now experimenting with fuel cells supplied by DaimlerChrysler.

Fuel cells tend to produce electricity from the heat that comes by converting oxygen and a supply of hydrogen into water. (The hydrogen can come from devices called “reformers” that pull the fuel from a supply of natural gas or methanol.)

As for diesel, it too is getting an alternative treatment of its own.

Biodiesel is produced by blending alcohol with vegetable oil, waste-frying oil, animal fats or waste from the pulp and paper industry, creating a sulfur-free fuel that can be blended with traditional petroleum-based diesel.

And the federal government found in a study of 150 Montreal buses that the fuel actually helped increase power under load and fuel efficiency.

This March, Topia Energy opened the nation’s first retail biodiesel pump in Unionville, Ont., and more are expected to follow.

“In Europe, there are over 800 biodiesel stations,” Topia’s Sam Goldberg says, referring to the growing acceptance of the fuel. “Two years ago there were no U.S. biodiesel filling stations and now there are over 100.”

Municipal fleets in Brampton, Guelph and Sudbury, Ont. have been using the fuel for the past two years.

Typically, biodiesel is available in a B-20 blend, which contains a mere 20 per cent biodiesel, since higher percentages tend to thicken in cold weather, leading to starting difficulties.

A similar approach involving ethanol is used in gasoline engines, with the blended fuel incorporating an alcohol made from the sugar or starch found in crops like corn or wheat. Since it contains less energy than gasoline, the makers of cargo vans that run on high levels of ethanol often compensate with larger fuel systems and modified ignition systems, although blends of 10 per cent can be used in any engine.

Natural gas, while used for longer than the other alternatives, has also survived as another fueling option.

Traditionally, it has been slow to emerge in the trucking industry because of the size of the cylinders that store the fuel, ranging from 11 to 44 litres, and reduced power at wide-open throttle. But it still shows promise in several applications.

Vancouver-based Cummins Westport, a joint venture of Cummins and Westport Innovations, recently provided Paris, France with 78 CWI B Gas Plus and C Gas Plus engines for use in collection trucks and street washers.

“This sale in France is further evidence of our international expansion efforts for both transit and refuse applications of our engines,” said Hugh Foden, president of Cummins and Westport Innovations. “We are seeing strong growth indicators in a number of our refuse markets,”he said.