It has been an article of faith among environmentally conscious folks that “zero emission” electric cars are environmentally ipsy pipsy. No exhaust, not even an exhaust pipe. So that has got to be environmentally superior to gasoline powered cars that, no matter how efficient, emit some exhaust gases. Right? Wrong.
First of all, if you have a nodding acquaintanceship with physics, to say nothing of thermodynamics, you know that, as the Romans used to say, Ex nihilo nihil fit. Or, as they say in New York, for nuttin’ you get nuttin’. What electric cars do is not somehow generate pollution-free energy, but only transfer the products of combustion of hydrocarbons from the car’s tail pipe to the power generating plant from which they draw the electrical current necessary to charge their batteries. The savings in air pollution, if any, may inure to the benefit of your immediate area, but on a global scale the pollution emitted from your tailpipe is only transferred to the area surrounding the power plant from which you draw power to charge your electric car (or plug-in hybrid).
Now, along come three spoilsports and tell us that electric, shmelectric, depending on where and when your electrical power is generated, your electricmobile may emit more air pollutants than a gasoline burning car. See Joshua Graff, Matthew Kotchen, and Erin Mansur, Are Electric Cars Greener? Depends, L.A. Times, Nov. 17, 2014, at p. A15. How can that be? Let the authors explain:
“We find, for example, that charging an electric car at night in the upper Midwest will generate more carbon dioxide per mile driven than the average conventional car that burns gasoline. In contrast, electric cars in the western United States and Texas always generate lower emissions than even a hybrid, and this arises because natural gas [which they burn] rather than coal tends to be used for generating the additional energy in these regions.”
And to make things more complicated, the efficiency of gasoline-burning cars has been moving up, so this calculation is affected by how efficient your old-fashioned gasoline burning car is. If you are a mileage freak and are willing to compromise, some gasoline-burning cars in some places turn out to be overall no more polluting than electrical ones. We do not suggest that you forgo a spiffy Tesla or a thrifty Prius, if that is what floats your boat. But don’t delude yourself into supposing that on a global scale you are performing feats of air pollution reduction. You aren’t.