The Tesla fans can probably give you the details -- although they're still a little wedded to cars. A coal plant can use filtering much more elaborate than anything a private vehicle can use, so reportedly a Prius (35 MPG) has about the same emissions as a Tesla fueled from an all-coal grid.
I don't disagree with your general point (although I'll quibble a bit about non-carbon emissions; even heavily scrubbed coal emits a lot of heavy metals that aren't present in gasoline).
But what Prius only gets 35 MPG? Did you mean 53MPG? My old Prius with batteries that are getting long in the tooth still gets 40-45 MPG.
