Most distribution centers begin their sustainability initiatives by reducing energy consumption. And one of the first places they look for savings is lighting.

Take Wal-Mart Stores, for example. At the Dematic-sponsored Material Handling & Logistics Conference in Park City, Utah, in September, Jeff Smith, senior director of logistics, maintenance, and purchasing for Walmart, detailed some of the steps his company has taken at its DCs to reduce energy use.

Over four years, Walmart retrofitted the lighting in more than 100 DCs, resulting in an annual reduction in electricity use of 1.9 million kilowatt-hours and yielding an annual average savings of $124,300 per facility.

Now, Walmart is making a further attack on DC lighting costs. In 2010, the retailer began pilot tests of LEDs (light-emitting diodes) in high-bay locations in its distribution centers. It replaced the fluorescent lighting in two DCs in Florida and Tennessee with LEDs this year. Smith said that if those tests prove successful, Walmart would launch another four-year project to install LED fixtures in all of its DCs.

Another company that can boast similar successes is the industrial distributor W.W. Grainger. In a separate presentation at the Dematic conference, Patrick Shurtliff, Grainger's senior manager, property management, said his company upgraded lighting in 16 branch facilities last year and expects to complete another 36 this year. One of its major energy projects was the installation of a 9,600-panel photovoltaic system on the roof of a New Jersey DC. Shurtliff said he expects a payback on the project in four years, thanks in part to a federal grant under the American Reinvestment and Recovery Act (ARRA) that paid for 30 percent of the project.