And that number keeps climbing. According to the California Solar Statistics website, the number of California roofs generating power from the sun reached 150,428 as of Wednesday, with a total generating capacity of 1,560 megawatts -- about equivalent to three typical coal-fired power plants.
Los Angeles County now leads the state in the amount of rooftop generating capacity, with 171.4 megawatts of rooftop solar installed. San Diego and Santa Clara counties come in second and third, at 141 and 110 megawatts respectively.
San Jose leads California cities in total rooftop solar capacity, at 59.4 megawatts, a 21-megawatt jump since summer 2012.
The stats are compiled from data on rooftop solar arrays hooked up to the electrical grid through Pacific Gas & Electric (PG&E), Southern California Edison (SCE), and arrays outside those utilities' service areas financed by the California Center for Sustainable Energy and GRID Alternatives. That means that rooftop solar in areas served by other utilities such as the Los Angeles Department of Water and Power or the Imperial Irrigation District may not even be included in these totals.
Nonetheless, it's a hopeful benchmark, and its passing didn't go unnoticed by solar advocates. "150,000 rooftop solar installations is clear evidence that Californians want clean renewable energy generation to keep expanding," said Evan Gillespie of the Sierra Club's My Generation campaign. "As California enters its summer season of high electricity demand, the energy generated from rooftop solar is providing more and more of the peak power that we need to avoid potential blackouts. With San Onofre Nuclear Generating Station shut down, these new solar installations will play a crucial role in the months ahead."
Gillespie did warn that the state's growth in rooftop solar isn't without obstacles, citing utility opposition to expanded net metering and feed-in tariff programs. "Unfortunately, all indications are that utilities would like to limit or even reverse the growth of rooftop solar in order to protect their business model based on bloated dirty fuel projects," he said. "From helping to keep the lights on to putting Californians back to work, rooftop solar provides so many benefits to the state. This is the time to move forward, not backwards."