Coal may make electric cars dirtier to run in the short term, Voelcker writes. But, in the long term, its electric cars that help make the case for rendering coal obsolete.
Every so often, electric-car skeptics will attack the idea of using grid electricity to power a car by bringing up coal.
"Yeah," the argument goes, "but you're just burning coal instead of gasoline in your electric car--so how's that any better?"
There is, of course, a fair amount of science that shows it actually is better when measured by wells-to-wheels carbon emissions.
The conclusion: Even in the few states with the very dirtiest grids, driving a mile on grid electricity is barely worse than the most fuel-efficient non-hybrid car (roughly 34 mpg).
And in states with the cleanest grids, there's no combustion-engine vehicle that can match an electric car for low carbon emissions.
A landmark 2007 study jointly produced by the Electric Power Research Institute (the research arm of the electric utility industry) and the Natural Resources Defense Council comes to broadly similar conclusions.