Cutting our energy use through innovation

Our buildings represent the largest piece of our carbon footprint that we directly control. From lighting and water conservation to refrigeration systems and building materials, we view our facilities as laboratories of sustainability.

In 2005, we committed to develop a store prototype that’s 25% - 30% more energy efficient by 2009. We met that goal in all of our global markets and continue to improve our buildings and become a more efficient company. For example, ASDA in the U.K. reduced carbon emissions by 11.9% from 2007 to 2011, despite opening 50 new stores and serving more than 2.5 million additional customers.

Discovering LED


LED lights in a Walmart store refrigerator case

Electricity represents the second-highest operating expense at the majority of our stores and clubs. So we discovered a game changer in 2005, when the installation of LED freezer case lighting at a store in McKinney, Texas, reduced energy consumption by 70%. Now LED freezer case lighting has become the industry standard and we’ve adapted the technology to additional areas of our buildings, including parking lot lights and sales floor lighting.

  • To date, we have converted parking lot lighting at 350 stores in Central America to LED.
  • LED parking lot lights are now part of our store prototypes in nearly all of our global markets.
  • In 2011, we opened a Neighborhood Market in Wichita, Kansas, and a store in Acapulco, Mexico with 100% LED sales floor lighting.
  • In 2011, we retrofitted six Walmart U.S. distribution centers with interior LED lighting. This investment will reduce energy use by more than 16 million kilowatt hours in 2012.

Secondary loop refrigeration

Refrigeration cases and walk-in coolers account for about 11% of our greenhouse gas emissions and are a bigger contributor to our carbon footprint than our truck fleet. In 2011, we became the first retailer in the U.S. to incorporate the secondary loop refrigeration system – a new system to increase efficiency, prevent leakage and cut greenhouse gas emissions by as much as 95%. This new technology will be featured in newly constructed Walmart stores.

Fly ash flooring

In 2011, we used 12,677 tons of fly ash – a byproduct of coal-fired electrical generation – and 2,475 tons of slag – a byproduct of steel manufacturing – in the cement flooring mixtures for our new U.S. stores. Every ton of fly ash saves the equivalent of one barrel of imported oil, or enough electricity to power the average American home for 24 days.

Harvesting rainwater

Our Best Price store prototypes in India filter storm water runoff from our rooftops and parking lots through layers of gravel and sand before reintroduction to the water table. They also capture and process wastewater from our facilities for reuse in processes, such as irrigation and flushing.