According to a report by the trade group Solar Energy Industries Association, a record 7,286 MW of solar PV was installed in the United States in 2015. While California, North Carolina and Nevada maintained their one-two-three rankings for new installation, more than 13 states installed over 100 MW each, demonstrating growing geographic diversification for solar generation. For the first time, new solar capacity exceeded new natural gas capacity and represented nearly 30 percent of all new U.S. generating capacity. 

For 2015, utility-scale solar grew 6 percent year-over-year and represented more than half of all new installed solar PV. Growth in the residential solar market soared by 66 percent year-over-year, with over 2 gigawatts of new installed solar. Residential solar has grown to comprise 29 percent of all U.S. solar capacity. The growth of solar, and particularly distributed generation, has drawn notice beyond the renewable and energy communities. Warren Buffett, whose Berkshire Hathaway has ownership interests in several utilities, wrote in his annual shareholder letter that solar and other renewables are pushing traditional utilities to improve their efficiency. Under the old monopoly model, Buffett writes, “a ‘sloppy’ operation could do just fine financially.” With solar and other renewables increasing their generating capacity and ability to compete on price, a poorly run utility is now likely to find itself in trouble.