Power plants operate at a much higher efficiency than internal combustion engines, on cheaper and more diversified fuel sources, including renewable.
[Electric motors and batteries also have relatively little energy waste, making the system as a whole more efficient to operate, especially when you consider being able to leverage the superior distribution infrastructure of the electric grid versus the relatively sparse network of fuel stations. Consider that most fuel stations receive their supply by tanker-truck, which introduces yet more inefficiency.]
A small common rail diesel engine in a car gets close to 40%, a coal power plant runs at about 45%.
Add in transmission losses and charging/battery/electric motor and the diesel g CO2/km is probably better.
The US is presently doing a lot to switch over to natural gas, which has a lot less carbon-per-kWh than coal. If that's what they have in your area, the figures look better. Also good for the figures: if you happened to be doing your charging off-peak such that you're not actually adding to the emissions that would otherwise be emitted by idling power plants. (Or if you live in an area with good hydro/nuclear and the like.)
Of course, that's not really transparent to the electricity user in most cases.
You should really check out modern diesels. A VW TDI engine has cleaner exhaust than a typical modern gasser. You could hold up a white handkerchief to the tailpipe and it'd stay clean.
Coal stations have flue gas sulfur filters, but still emit a lot of CO2 (and a lot of radioactivity), road diesel is ultra low sulfur in civilized countries.
[Electric motors and batteries also have relatively little energy waste, making the system as a whole more efficient to operate, especially when you consider being able to leverage the superior distribution infrastructure of the electric grid versus the relatively sparse network of fuel stations. Consider that most fuel stations receive their supply by tanker-truck, which introduces yet more inefficiency.]