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.
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.