Solar power, which makes up a tiny part of California's overall energy mix, will account for the biggest piece of the state's renewable energy pie by the end of the decade, according to the state's largest utilities.
Last year, Pacific Gas & Electric got most of its renewable energy from wind, bioenergy, geothermal and small hydropower dams. Solar accounted for about 1 percent. But that mix is quickly changing, and by 2020, the San Francisco-based utility expects solar to account for 40 percent of its renewable portfolio.
California's aggressive "Renewable Portfolio Standard" law requires utilities to purchase 33 percent of their electricity from renewable sources by 2020. Bioenergy, geothermal, solar, wind, wave and tidal power and small hydroelectric dams -- which cause less harm to the environment than large hydro dams -- all count toward meeting the law.