Wal-Mart Truck Fleet Rolls Fuel Savings

A Wal-Mart truck passes over the Susquehanna River on Interstate 81 in Harrisburg, Pa., in this May 9, 2006 file photo. (AP Photo/Carolyn Kaster, file) (Carolyn Kaster - AP)

The targets set by Scott in December 2005 were a 25 percent improvement in three years and a 100 percent increase by 2015.

The federal Environmental Protection Agency estimates that Wal-Mart's goal of 25 percent will reduce its fleet's emissions of carbon dioxide by about 345,000 tons a year. Doubling fuel efficiency will cut out over 690,000 tons a year.

That latter target would cut carbon emissions by the same amount as getting rid of 135,489 passenger cars or about one 225-megawatt power plant, according to the Alliance to Save Energy, an industry group.

The Sierra Club's Becker says those savings are "nothing to sneeze at" for a single fleet, considering that new fuel efficiency standards for passenger vehicles under debate in Congress would cut 285 million tons of CO2 annually in 2020 from the much larger number of cars, light trucks and SUVs.

Wal-Mart's Yatsko said the fleet is already running about 15 percent more efficiently at an average of about 7 miles per gallon compared to a 2005 base of about 6 mpg.

Increasing the average mpg by one gallon saves Wal-Mart between $35 million and $50 million a year, Yatsko said.

The 15 percent gain has come mainly from three changes: A fuel additive mix, more fuel-efficient tires and small diesel generators called Alternate Power Units added to tractors to provide power for things like heating and air conditioning in the cab, allowing the big truck engine to be turned off rather than idling when the truck is parked.

Yatsko says Wal-Mart knows where the remainder will come from to meet the 25 percent target by late 2008.

New trucks that are already coming to market will yield about 8 percent more efficiency due to more aerodynamic design and lighter components. Another few percentage points will come from tire innovations that Yatsko said he is not ready to make public just yet.

Yatsko said that the 25 percent gain will apply to most of the fleet but not to all of it by late 2008. Wal-Mart will need to switch out its older trucks over time but expects to have at least half the fleet up to date with the most efficient trucks by the end of 2008 and the rest completed by 2010.

As the retailer continues to look for fuel gains in components, driving practices, tires, fuel and other areas, the total effect could be a savings of 28 or 30 percent from the 2005 base by the time the entire fleet is updated, Yatsko said.

That leaves the 100-percent goal.

Yatsko says the biggest piece of the solution will come from future hybrid diesel-electric engines. Wal-Mart is pitching in $2 million a year for research and development by two teams of national truck manufactures _ International Truck with ArvinMeritor Inc. and Peterbilt with Eaton _ and has agreed to buy the prototypes.

New hybrid engines will deliver about a 50 percent efficiency increase on top of the 25 percent set for next year, Yatsko said.

Wal-Mart is also working with Great Dane on prototype trailers that would cut fuel use with the help of aerodynamic designs, including adding a cover or skirting down the sides at the bottom of the truck and crimping the back end of the trailer so that the sides and top turn in.

The effect of that back end design could add 5-6 percent to fuel efficiency by cutting wind drag, Yatsko said.

All of this work has to pay for itself, Yatsko said. Changes and additions to the fleet have to provide a return on investment or they cannot be sustained, he said.

"I definitely think we're leading the industry," Yatsko said.