Up close, an electric vehicle is clearly cleaner than a gasoline-powered car. No matter how efficient a combustion engine becomesâ€”and some gasoline-powered cars can be very efficientâ€”it still, well, combusts, spewing carbon and other exhaust gases into the atmosphere. But nothing at all comes out the tailpipe of an electric car. Itâ€™s as clean as it is silent.
But thatâ€™s just up close. The electricity used to power an electric carâ€™s battery has to be generated somewhereâ€”and depending on the source of that power, an EV may be less than squeaky clean. Thatâ€™s the takeaway of a new report (PDF) by the Union of Concerned Scientists (UCS). UCS used the electrical power requirements of the Nissan Leaf and estimated how much greenhouse gas the car would be responsible for if it were charged in different parts of the country. No big surprisesâ€”the more coal or gas-heavy a stateâ€™s electricity profile is, the more carbon the electric car would be responsible for. So in relatively clean Californiaâ€”where hydro, nuclear and renewables supply most electricityâ€”the Leaf would produce as much carbon as a gasoline-powered car that got 79 miles to the gallon. In coal-happy Oklahoma, though, it would be comparable to a 37 mpg car. If youâ€™re driving in the middle of the country, the climate would actually be better if you picked a hybrid like the Prius or even a highly efficient gasoline-powered car rather than an EVâ€”and support policies that can shift electricity away from carbon-intensive coal.