China and India both aspire to embrace electric cars to cut petroleum dependence over the next decade. But there’s a big reality check: Electric cars are only as clean as the power sources that charge them. So far, in both of these rapidly changing markets, the electrical grids are quite dirty.
Both China and India fall into a group of nations in which EVs aren’t much better for carbon emissions than some of the more efficient gasoline-powered cars. Based on new calculations from Michael Sivak and Brandon Schoettle of the University of Michigan, a gasoline car in India needs to get almost 36 mpg to achieve lower carbon emissions than a typical battery-electric vehicle. In China, the figure is 40 mpg.
In other countries, by and large, figures favor the EV in a much more promising way. On a global average, you’d need to get 52 mpg to rival plugging in, while on average in the United States, a gasoline-powered car would need to get 55 mpg to be cleaner than EVs charged from the grid.
Among the 12 nations in the world with the largest economies, France stands out as having the lowest emissions associated with plugging in—a gas car would need to get the equivalent of 525 mpg to match an average battery-electric vehicle there—while Canada and Brazil follow with the equivalent of more than 150 mpg. Germany, the United Kingdom, Italy, and Russia all weighed in above the global average, while Japan, India, and South Korea were all below the global average.
The researchers behind the report produced a world map [below] ranking 143 of the 195 “currently recognized sovereign states” in the world, ranking them in four color-coded groups.
It’s All in the Mix
Those scientists calculated that electricity generated using coal and oil was equivalent to 29 miles per gallon of gasoline, while natural gas was the same as getting 58 mpg. Geothermal and solar sources were rated at 310 and 350 mpg, respectively, while nuclear, wind, and hydro sources were in the thousands of miles per gallon.
The averages were based on an EPA-rated efficiency of 102 miles per gallon equivalent (MPGe)—0.33 kWh per mile—for electric vehicles. That happens to be the MPGe rating for both the 2017 Tesla Model S 100D and the Smart Fortwo Electric Drive cabriolet. At present, the EPA lists 18 trims or models with even better efficiency than that. So in the United States, or pretty much anywhere, electric cars do much better on carbon emissions than most gasoline vehicles.
But as for how much better? It depends. It depends on your local and regional utilities and where they get their power; and it even depends on the time of day. The figures also don’t include the cradle-to-grave emissions involved in manufacturing vehicles or their batteries—or in how materials are sourced.
On the other hand, they don’t include another important point: A gasoline vehicle isn’t going to emit any less at the tailpipe as it gets older, although it’s likely that over the life of an electric vehicle, energy replenished from the grid will keep getting cleaner—whether in China, India, or your own garage.