First of all, if you really want to improve the environment the best way to do so is to not buy any vehicle at all. Every car, electrical or not, even when it is never used is an enormous expenditure in both energy (and therefore greenhouse gas emissions) and raw materials simply because it has to be manufactured. So if you want to do the best possible thing for the environment cutting down on your traveling and working hard to avoid the purchase of a vehicle are the two best things that you could do when it comes to transportation.