I've been told that the loss in long distance powerlines is way more than the 7..10% that is acceptable for short on-site powerlines (which are more limited by considerations such as reliable functioning of fuses and insulation than the long distance high voltage lines as far as I understood)
I'll try to find some data on this now.... But keep in mind that the efficiency of our little engines will be worse than 30% when it comes to converting the chemical energy in gasoline to actual work... Although I wouldn't be surprised if the efficiency figures for coal powerplants are flattered in some way, there are serious commercial and political interests behind those...
Update : the figures for power losses between plant and user accourding to a few sources that I found vary from an optimistic 7..10% on a single wikipedia page to 15..17% in a number of other documents, add to that the losses of the powerplant itself, which for coal plants can be larger than 50% (!), the powersupply losses for the battery charger, thermal losses in the battery during charging and discharging and the efficiency of the motor and transmission itself..... My rough estimate is that the resulting overall efficiencies are quite comparable between a gasoline vehicle and an electric one...
The obvious advantage of electrical vehicles is that they can be charged with energy from renewable sources. But then again you must ask yourself how much of the energy that you use in your country is generated from non-renewable sources, to know if it's really eco-friendly to dump your gasoline drinking Kymco in a landfill somewhere and go electric