Fall fire weather isn't anything new for Californians. It's usually hot, dry and windy this time of year. What is new, however, is the state's largest power companies shutting off electricity for hundreds of thousands of homes in the hope of preventing their power lines from sparking wildfires. … "When you meet your electric demand only with local resources, it's possible, but the amount of energy storage you need increases and that makes it more expensive," said Brian Tarroja, professional researcher in civil and environmental engineering at the University of California, Irvine.