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February 06, 2009

Walmart Will Double the Efficiency of Their Fleet of Cars and Trucks by 2015


From Green Car Congress: Wal-Mart Stores has set of goal of increasing total fleet efficiency by 100% from 2005 to 2015,
and has already exceeded its 2008 interim goal of a 25% increase, according to Chris Sultemeier, Wal-Mart’s Senior Vice President of Transportation.

Total fleet efficiency is a combination of driving and operational practices as well as the vehicles, Sultemeier said. Of the current 25%, about 20% is likely due to vehicle technology, he said. Looking ahead to the 2015 goal, about 50% could come from the vehicle, 50% from the operational side, he said in a teleconference.

Wal-Mart has taken a number of steps, including the installation of diesel APUs [Auxiliary Power Units - explained below] on all its trucks, and applying aerodynamic skirting. On the tire side, Wal-Mart is working with super single tires. and is testing nitrogen-filled tires and an automatic filling process to maintain constant tire air pressure.

Aerodynamic Skirting
At 70 mph, 65% of a trucks fuel is used to overcome aerodynamic drag.

Aerodynamic skirting - Freight wing - can increase fuel mileage by 6-7%.



Aerodynamic modifications of cars has been examined at this site before. It is possible to improve highway fuel efficiency by 15-40% with an aerodynamic retrofit.


There is a 56 page guide on aerodynamics for freight trucks









Auxiliary Power Unit
A diesel auxiliary power unit (APU) reduces the fuel used during idling.

Vehicle Engine
Idle hours/year 2180
Fuel Consumption (gal/hour) 1
Average Fuel Cost ($/gal) 2.18

Diesel APU (five times more fuel efficient)
Cost ($) 10,000
Fuel Consumption (gal/hour) 0.2
Average Fuel Cost ($/gal) 2.18
Pay back period (years) 2.6

On the operational side, probably the key is getting more on the trailers. When we talk about efficiency, if you can take miles off the road, that’s huge—that’s bigger than things we can do around the equipment.

Operational efficiency : year to day they have shipped 150 million more packages but driven 90 million fewer miles.

Looking ahead on the vehicle side, Wal-Mart is currently pursuing four paths of investigation: hybrid assist technology; full hybrid technology including all-electric drive (approx. 20 minutes at 48 mph or less); LNG; and biofuels.

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