It’s been said before but I’m glad that David Biello repeats it in his Scientific American article. The carbon emissions that result from the use of electric vehicles depend on how the electricity they employ is produced:
Driving an electric car in China, where coal is by far the largest power plant fuel, is a catastrophe for climate change. And if the coal plant lacks pollution controls—or fails to turn them on—it can amplify the extent of smog, acid rain, lung-damaging microscopic soot and other ills that arise from burning fossil fuels. The same is true in other major coal-burning countries, such as Australia, India and South Africa.
The good news: the U.S. is making a tectonic shift from burning coal to produce the majority of its electricity to using cleaner natural gas. The changeover produces less CO2, making electric cars cleaner across the country, roughly equivalent to a hybrid. On the other hand, the primary constituent of natural gas—methane—is itself a potent greenhouse gas. If methane leaks from the wells where it is produced, the pipelines that transport it or the power plants that burn it, the climate doesn’t necessarily benefit.
In short, electric cars are only as good as the electricity that charges them.
There’s also some question about just how non-polluting electric vehicles are, as this article at Wired explains.
Nothing is ever simple.
