ROBYN BECK/AFP/Getty Images
Some of the 24,000 mirrors called "heliostats" at the eSolar Sierra SunTower power plant in Lancaster, California in the Mojave Desert approximately 70 miles (110 km) north of Los Angeles May 12, 2011. eSolar's concentrated solar power (CSP) system uses the movable heliostats to reflect solar heat to a thermal receiver mounted atop two towers. Electrical power is produced when the focused heat boils water within the thermal receiver and produces steam, which is then piped to a nearby reconditioned 1947 GE turbine generator to produce electricity. Sierra SunTower is the only commercial CSP tower facility in North America.
California is home to more than half of all rooftop solar projects in the United States. But as more and more Californians generate their own power the state's big utilities are getting worried.
KQED's science reporter Lauren Sommer has the story.