Energy storage developers have been saying for a decade that the industry’s on the verge of a big breakthrough that will finally turn the battery into a major player in the power market. At least this time around, they’ve got customers backing them up. Utilities Southern California Edison and San Diego Gas & Electric said at a storage conference last week that supply from batteries now competes against natural-gas fired plants that start up when demand peaks. Storage developers are inking deals with big corporations including InterContinental Hotels Group Plc and Whole Foods Markets Inc., which want to install storage units to save on power bills. Batteries account for a tiny fraction of global power resources. The technology has been prohibitively expensive and, until recently, relatively unproven. The U.S. government’s Argonne National Laboratory, the same one that built the first nuclear reactor to generate power, just offered its help […]