Walmart U.S. truck fleet
In 2011, we achieved almost 69 percent improvement in fleet efficiency over our 2005 baseline. Throughout our network, we delivered 65 million more cases, while driving 28 million fewer miles, by increasing our pallets per trailer and better managing our routes. The heavier loads have minimal impact on our fuel-efficient equipment, which includes an average tractor age of three years and the addition of more than 13,000 skirted trailers. Our network efficiency improvement equates to avoiding nearly 41,000 metric tons of CO2 emissions, the equivalent of taking about 7,900 cars off the road.
Leading the industry in the development of fleet technology
Walmart U.S. Logistics is an industry leader in the development and testing of advanced technologies to improve the efficiency of Class 8 heavy-duty trucks. In partnership with truck and component manufacturers, we have built a number of prototype tractors with the goal of learning from testing in a real life environment to improve the technology. Like many emerging technologies, these trucks may never enter operation or may not remain in operation long as they go through multiple iterations before being cleared for commercialization. We are already working on many next generations.
- Hybrid assist
- Hybrid assist tractors utilize a traditional diesel drivetrain in conjunction with an electric motor to recover energy normally lost during braking to provide additional torque in high-load situations like going up hills. The onboard batteries are also used to run components such as heating, air conditioning and the electrical system when the engine is off. This model was our first hybrid tractor and was built in partnership with Peterbilt and Eaton Corporation. Over the course of a year, we gathered data and highlighted key areas of opportunity (e.g., batteries) needed to achieve an acceptable return on investment. Hurdles for the batteries include cost, size and weight, and capacity.
- Wheel-end hybrid assist
- The concept of this hybrid, built in partnership with Freightliner, is similar to the one above, except for the placement of the electric motor. This tractor has two wheel-end motors on the second axle, putting the energy right where it is needed and avoiding energy loss from the front of the tractor. Already under development, the next generation of this tractor will attempt to resolve the inability to add future enhancements, such as stationary recharge of the hybrid battery due to current motor placement.
- Full propulsion hybrid
- This configuration is a dual-mode hybrid with the ability to run completely on its electric motor when traveling under 48 miles per hour. When it passes that mark, it switches over to a diesel engine. This hybrid, built by Meritor, was the first of its kind in this class when unveiled. Similar to the hybrid assist tractors, the next generation of this hybrid drive system is under development, being paced by the design of a battery system with enhanced performance and improved robustness.
- Natural gas
- Walmart has been testing five Westport Liquid Natural Gas (LNG) trucks in California for the past three years, and has just taken possession of a Westport/Cummins Alpha 12-liter natural gas engine. This new truck will run on compressed natural gas (CNG) and will also be tested in California. Although available fueling infrastructure is a challenge, the technology performance and potential sustainability benefits encourage further review.
- Technology truck
- In our continuing quest for improved efficiency, considerable opportunity lies in improving the individual components of the truck. To that end, Walmart and Freightliner worked together to build an advanced, aerodynamic tractor with the latest in efficiency and predictive technologies. Testing will allow for the evaluation of individual components as well as the interplay of multiple components. This tractor was built with further development in mind and will be retrofitted with new advancements as they become available.
These and other technologies, along with innovative operational initiatives, are moving us toward the goal of doubling our fleet efficiency.
International fleet improvements
Alternative fuel sources
We conducted a series of trials with alternative fuel sources in 2011, including CNG, and identified opportunities to reduce both our carbon impact and cost of fuel. In the U.K., we view CNG as a leading sustainable fuel source of the future and are developing a business case to introduce this technology to a wider percentage of our fleet.
In December 2011, Walmart India began piloting the use of shipper boxes to transport frozen food to several long-distance delivery stores. These innovative shipping containers utilize dry ice to keep products frozen regardless of shipping distance. The cooling blankets we used in the past were effective only on shorter routes. Shipper boxes have the potential to expand the reach of our cold supply chain by bringing frozen food to more customers without the use of refrigerated trucks, which consume considerably more energy. This translates into a wider variety of refrigerated products for our customers and a cleaner environment for everyone. We are reviewing opportunities to expand this program to meat and other perishables.
We are piloting the use of roll containers and pallet covers, packing devices that utilize dry ice or other cooling technology, rather than diesel or electricity, to keep merchandise refrigerated. This would enable us to pack refrigerated and dry merchandise on the same, nonrefrigerated truck for delivery to our smaller format stores. These methods have the potential to reduce our number of outbound trucks, while lowering transportation costs by 25 percent.
Focus on efficiency
Over the past five years, our transportation department in Mexico has demonstrated continued improvement in the area of efficiency. In 2011 alone, our focus on backhauls, the practice of picking up a load from a vendor and delivering to our distribution centers (DC), rather than running an empty truck between our store and DC, saved more than 56,000 trips. Combined with other initiatives across our transportation department, we saved more than 86,600 trips and nearly 3.2 million miles, while avoiding 4,878 tons of CO2 emissions.