For most of the year, California's quest to rid itself of fossil fuels seems on track: Electric cars populate highways while energy from wind, solar and water provides much of the power for homes and businesses.
Then it gets hot, and everyone in the nation's most populous state turns on their air conditioners at the same time. That's when California has come close to running out of power in recent years, especially in the early evenings when electricity from solar is not as abundant.
