Driving fleet efficiency

Walmart operates approximately 6,000 trucks pulling millions of loads each year in the U.S. While the domestic fleet accounts for our largest portion of company-owned trucks and trailers, globally we also maintain other private fleets and work directly with third-party transportation providers to keep store and club shelves stocked.

Since 2005, we have been working hard to reduce our fuel footprint through our goal to double fleet efficiency by the end of 2015. In pursuit of that goal, Walmart U.S. Logistics continued to drive savings in its transportation operations, achieving an 84.2 percent improvement in fleet efficiency over our 2005 baseline. Industry-leading innovation in both equipment and operations resulted in this 4 percent increase over 2012.

In terms of transportation as a whole, we delivered nearly 181 million more cases, while driving almost 167,000 fewer miles in 2013 as compared to 2012. Had we not improved our efficiency, we would have driven 34 million more miles than the previous year to deliver the additional cases. Every mile not driven is fuel not burned. That efficiency saved the company nearly $65 million and avoided almost 25,000 metric tons of CO2, which is the same as taking 5,000 cars off the road.

Walmart associates and our vendors work in multiple ways to continue to drive efficiency. The primary means we have at our disposal include:

• Effective driving techniques, such as minimizing idle time and progressive shifting, to ensure optimal performance from equipment
• Advanced tractor-trailer technologies that increase efficiency, like electrification, light-weighting, improved aerodynamics and fuel-efficient tires
• Improved processes and systems that drive more efficient loading and routing of merchandise

Moving forward: Walmart’s Advanced Vehicle Experience

Reaching our goal by the end of 2015 will require careful execution of identified efficiencies, as well as a commitment to finding new breakthroughs. Driving toward this, Walmart unveiled its technology demonstration vehicle featuring leading-edge aerodynamics, electrified auxiliaries (A/C, steering, air compressor) and a scalable prototype advanced microturbine-powered range-extending series hybrid powertrain. The objective of our concept truck is to test and learn from a wide range of technologies that could improve the overall fuel efficiency of our fleet, as well as contribute to our ability to transition to alternative fuels, reducing our overall carbon footprint.

Built in collaboration with Peterbilt Motors and Capstone Turbine Corporation, the truck’s shape represents a 20 percent reduction in aerodynamic drag compared to our current Peterbilt Model 386, one of Walmart’s standard fleet vehicles. By placing the cab over the engine, the wheelbase of the truck can be greatly shortened, resulting in reduced weight and better maneuverability.

The prototype powertrain takes two proven technologies and combines them in a way that takes advantage of the key strength of each. While common in other applications, turbines haven’t been used in road vehicles because their efficiency is based on constant engine speed; therefore, they are adversely affected by the regular acceleration and deceleration of truck travel. By combining the Capstone microturbine with a hybrid-electric drive system, and using it only to charge the batteries rather than as the main engine, the turbine runs in its optimal environment. This takes advantage of its increased efficiency as compared to the conventional internal combustion engine.

Other key advantages of most turbines are their fuel neutrality and reliability.Microturbines will accept most types of fuel, from diesel to natural gas to advanced biofuels, and produce very low emissions without the need for after-treatment. Their few moving parts result in lower maintenance and longer life expectancy.

The trailer, built by Great Dane, is almost exclusively carbon fiber, saving almost 4,000 pounds. The roof and sidewalls are made from single-piece, 53-foot carbon fiber, and the use of advanced adhesives eliminates the need for most rivets. The solid, one-piece floor reduces weight without sacrificing strength or performance. The convex nose shape enhances aerodynamics while maintaining cargo capacity, and next-generation, low-profile LED lighting is more energy efficient and less prone to damage.

Moving forward: Operations

Reducing the fuel used in our operations requires a commitment by the entire Logistics division to try to ensure every trailer is loaded to optimal capacity, routed the smartest miles to its destination and safely delivered on the most efficient equipment. Every function plays a role: the associates loading and receiving trailers, the truck drivers, the maintenance technicians, the dispatchers and the strategists. And the closer we get to our goal, the harder our teams must search to find opportunities for the remaining 20 percent.

Sometimes those improvements are found in sophisticated systems and technologies, while others are found by stepping back and rethinking processes. In one instance the opportunity was found, quite literally, by stepping up rather than stepping back. At times, general merchandise trailers can’t be loaded to capacity because many associates can’t reach the top. By using a two-step safety stool, we were able to increase trailer fill by nearly 3 percent. In addition, on the grocery side, a new load designer system identifies unused space and more accurately designates pallet positions on the trailer for optimal loading/off-loading in our complex tri-temp and multistop operation.

Many of our efficiencies are driven by systems, so data inaccuracies can have a tremendous impact on our operations. Item files, used to build out a load, describe the size and weight of the cases we carry and may be inflated, leaving unused space in the trailers. Our teams have been working closely with suppliers and distribution center teams to increase the accuracy of the item file, which results in increased trailer fill.

Working as a team within Logistics is important for efficiency, but collaboration across the organization with our store and club partners is critical. Effective ordering and delivery schedules are fundamental to filling trailers and reducing miles. As demand and product mix change throughout the seasons, our strategy team responds by altering deliveries to match need rather than a fixed schedule. For example, if a store or club normally receives deliveries seven days a week during peak season, their schedule is changed to five or six days during slower periods, which keeps the trailers as full as possible and eliminates the miles for the extra deliveries.

Moving forward: Alternative fuels

Current efforts are focused on natural gas. Our first test of compressed natural gas (CNG) as a truck fuel was in 1989 in New Braunfels, Texas, with a subsequent test in 1993 in Porterville, Calif. The latest testing of liquid natural gas (LNG) began in 2009 at our Apple Valley, Calif., distribution center. In 2012, we were one of the first companies to receive the new Cummins Westport ISX 12-liter engines, and that test continues today. The evaluation of both LNG and CNG includes performance and reliability of the equipment, maintenance impacts, fuel economy, access to fuel, overall cost and life cycle sustainability.