They don’t call Energy Secretary Steven Chu the smartest Obama cabinet member for nothing. When he recently scoffed at worries that gas-electric hybrid cars heralded by the president were sales stinkers, we started asking around, only to find out that he is right. Take the GM Volt. Early sales were in the low hundreds, but demand has surged and insiders say sales should top 10,000 this year. That number could reach 90,000 next year, say industry officials. And just imagine what a hit they could be when a 500-mile battery for cars, one of Chu’s favorite projects, becomes available. The timing couldn’t be better for automakers. They must have a fleet average of 35 miles per gallon by 2016 and there’s talk the feds might raise that to 62 mpg by 2025.