Retail giant Wal-Mart will nearly double the number of stores where it uses solar energy technology, including numerous locations where it will deploy next-generation thin-film panels. Wal-Mart has also begun installing wind turbines at some of its stores and is experimenting with geothermal energy systems to reduce heating and air conditioning use, the company said. Wal-Mart, which has installed solar panels at 31 of its 8,400 stores since 2007, will soon add solar technologies at 20 to 30 additional stores in California and Arizona, providing up to a third of the energy at the stores.
More than half of the new stores will use thin-film technology, including cadmium telluride and copper-indium-gallium-selenide systems, which are less material-intensive than the traditional silicon cells. Because it is lighter, thin-film technology can be used at more locations, including in states where snow accumulation makes use of heavier panels impossible. While the technology has been around for years, it is less efficient than traditional panels. Recent advances, however, have made thin-film technology more practical for larger rooftops.