|How about an all-electric RAV4 for your trips to the Wasatch Range?|
For example, an article by Andrew Revkin on his DotEarth blog in October describes a UN report that concludes that in China "electric vehicles produce more CO2 per mile than a gas powered car because the power source is coal (my emphasis)."
However, one of the co-authors of the UN report, Lucia Green-Weiskel, comments later in the article that the situation in the US is, as a whole, not as bad as China because 50% of our electricity comes from less carbon-intensive sources (e.g., hydro, nuclear, natural gas, wind, and solar) and only ~45% comes from coal. Nevertheless, in Utah, 81% of the electricity is produced by coal, so EV usage here would likely be more carbon intensive than the US as a whole.
I personally see many benefits from an EV revolution and hope it happens. The above analysis is provided merely to illustrate the importance of an end-to-end analysis of costs and benefits from energy production to energy consumption. Emissions change with a transition from gas to electric powered cars, but don't necessarily stop. Much depends on how and where the electricity is produced.