Tesla has advertised its vehicles as having zero emissions, helping fuel the mania for the fun-driving sedan, but that's not necessarily true. Although the battery-powered car itself doesn’t produce any emissions, the power plant that generates the electricity used to charge those batteries probably does. Low emissions, much less zero emissions, are only true in certain places where most of the electricity comes from a mix of low-carbon sources such as the sun, wind or nuclear reactors.
Electric cars are great for eliminating oil from transportation. But electric cars may or may not help combat climate change—and it all depends on where the electricity comes from.
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.
Electric cars are only as good as the electricity that charges them. (A fuel’s source also matters for conventional cars; gasoline derived from tar sands is more polluting than that from most other petroleum resources, for example.) In the absence of clean electricity, hybrid cars that can travel 50 or more miles on a gallon of gasoline produce the least emissions.
Their environmental benefit—dubious for now, until more power plants get off coal—is not very worrisome. The current shift back to SUVs that guzzle much more petroleum than other cars, prompted by low gasoline prices, is a more worrisome sign for future climate change. Perhaps by the time electric cars are ubiquitous, pollution from generating electricity will be zero.
by David Biello (adapted)