New research published in the Environmental Science & Technology journal this month has concluded that the widespread adoption of hybrid and all-electric vehicles wouldn't drastically reduce the emission of harmful gases in the United States. Looking at carbon dioxide, sulphur dioxide, and nitrogen oxides, the study's authors point out that "passenger vehicles make up a relatively small share of total emissions" — only 20 percent of all carbon dioxide — so even if we all jumped into a BMW i8, that wouldn't by itself fix the problem of air pollution. Moreover, the research reiterates the perennial complaint about electric cars: they nullify the pollutants coming out of the car itself, but also increase pollution from power plants that have to produce their energy.
Produced by North Carolina State University, this study is based on modeling the gas emission patterns over the next 40 years while altering energy system variables like oil prices and battery cost. At its most optimistic, it suggests that by 2050 some 40 percent of cars in the US would be either hybrids or entirely electric, however even then the researchers "do not see a noticeable reduction compared to even 0 percent EDV deployment."
The way we produce energy matters more than the way we consume it
Lead author Joseph DeCarolis tells The Verge that the findings should not discourage people from buying electric vehicles, which can still be helpful in relieving the country from its oil dependency or improving urban air quality. He also warns against drawing any sweeping conclusions and points out that the key issue going forward will be "the emissions intensity associated with the electricity being consumed by the plug-in hybrid and battery electric vehicles." That's to say that if EVs are to prove themselves better for the environment over the long run, it'll be because of the way we generate the electricity feeding them, not because of the cars themselves.