"Lots more research is being done on calculating “grams of CO2 (or equivalent) per mile” as a way to compare electricity and gasoline. If global warming is your big issue, this is the one that many people look at. This also is highly locally variable, with very high numbers in the coal states and nice numbers in the hydro and nuclear powered areas."<p>With any luck we'll see decisions about energy that are much more locally relevant. If we can get our energy "tagged" with its source content (nuclear, coal, etc), we can make more informed decisions. I, personally, don't think shifting energy needs to coal is that much of a gain -- at least not enough to make me want to go get an electric car.