Of those million vehicles in the US, California will likely account for about a third, while states such as Connecticut, Maine, Maryland, Massachusetts, New Jersey, New York, Oregon, Rhode Island and Vermont will account for another third. In the Golden State, plug-ins may account for a fifth of all vehicle sales within a decade.
Such numbers factor in a growth rate of about 20 percent a year. Last year, there were about 133,000 plug-ins sold in North America. Unfortunately, there's been little proof this year that Americans will boost plug-in vehicle purchases by 20 percent. Through May, US plug-in vehicle sales were down about five percent from a year earlier to about 40,000 units, which is an awful long way from a million. But at least the future looks bright.