According to a Laerence Livermore National Lab study,

You should discount the estimation by anyone in a new energy industry by at least a factor of 2. The photovoltaic cost will approach 10 cents per kwh, in comparison with 3-4 cents per kwh from coal. Currently most electricity is produced by coal (50%) and NG (25%). That electriccal cars produce less pollution is only meaningful to city dwellers. Because this approach simply shifts the emission to power plants. Globally, we still produce similar amount of CO2 if the electrical cars have the same energy conversion rate (taking into account of every link). If electrical cars have a lower energy conversion rate (I think this is the case), then we produce more CO2 indeed. Although it is noted that CO2 is easier to be captured in power plant than from cars.