Wal-Mart Energy-Efficient Retail Store

The Wal-Mart store in City of Industry, Calif., uses half the energy of a typical new California store, thanks to advanced lighting and efficient, downsized climate control system. In place of ordinary opaque roofing, the store has an 18-kilowatt solar photovoltaic canopy. Annual energy savings are estimated at $75,000 to $80,000, which means a three-year payback of the added cost of the equipment. Southern California Edison, the local utility, provided a $170,000 incentive that shortened payback to less than one year. But rewards are much greater than that: Wal-Mart’s decision to use skylights was sparked by the stunning success of its “Eco-Mart” store in Lawrence, Kansas. In a cost-cutting move, the company installed specially designed skylights over just half the store, leaving the other side without daylighting. Managers using Wal-Mart’s famous real-time inventory system quickly found that sales per square foot were significantly higher in the daylit half of the store, and higher than the same departments in other stores.