So far, solar energy is a toy for the affluent. The George Washington University Solar Institute reported earlier this year that of the some 645,000 U.S. homes and businesses with rooftop solar panels, no more than 5 percent were households earning less than $40,000 a year. On Tuesday, the Obama administration announced an initiative to help low- and middle-income Americans gain access to solar energy. The administration said it intends to triple the capacity of solar and other renewable energy systems it installs in federally subsidized housing by 2020. The government will make it easier for homeowners to borrow money for solar improvements and start a nationwide program to help renters gain access to solar energy.