GRID

Electric cars have no tailpipe emissions when running. But unless they're charged entirely on renewable energy—still statistically unlikely today—there are emissions associated with generating the electricity used to charge their batteries. For several years now, rigorous "wells-to-wheels" analyses of the carbon-dioxide emissions associated with electric-car use have shown it's far lower than that of the average vehicle sold today. DON'T MISS: Different map shows electric cars are cleaner The Union of Concerned Scientists released an updated version of its MPG-equivalencies map...