Southern California Edison March 10 signed a deal with SunPower Corp. for 200 MW of photovoltaic power. The agreement is part of Edison’s plan to invest in 500 MW of solar power slated for warehouse rooftops in the Inland Empire, which would feed into the utility’s distribution system. Half of the power--250 MW--is to come from independent solar generators. Previous PV warehouse installations were announced by Edison, but are dwarfed by the size of this week’s deal. “The anticipated benefits of this agreement with SunPower include panel costs that will allow us to meet our commitment to increasing our customers’ supply of renewable energy while reducing the cost of installed solar photovoltaic power in California,” stated John Fielder, Edison president. Prior to this 200 MW agreement, in December 2008 Edison made news for throwing the switch on a small corner of its 250 MW photovoltaic system expected to be installed on leased warehouse roofs. This 2 MW thin-film solar project supplying peak power sits atop a giant ProLogis warehouse rooftop in Fontana. Last June, state regulators approved Edison’s request to own and build 250 MW of commercial rooftop solar systems over five years. The California Public Utilities Commission June 18 also required the utility to solicit a like amount of power from independent developers (Circuit, June 19, 2009). The utility is allowed an 11.5 percent rate of return based on its investment in the rooftop solar systems irrespective of how much energy actually is produced The commission found Edison’s proposed $962 million capital cost estimate reasonable but required that the costs be monitored. The 500 MW plan was embraced largely because the solar units are set to feed into the existing distribution system and avoid the environmental and economic hassle and costs of new transmission lines. This week, the utility noted that its engineers are slated to study the impacts of a large amount of PV feeding into its distribution lines and how to adapt circuits to accommodate the large installations. The technology Sunpower will deploy under this week’s agreement with Edison is aimed at integrating into a single unit a solar panel, frame, and roof mounting system, which reduces installation time and costs.