Do electric vehicles always help to reduce pollution?

The environmental impact of electric vehicles (EVs) depends on how the charging electricity is generated and the outside temperature when the EV is driven. In the U.S., 60% of electricity is generated from burning fossil fuels. Moreover, the extra electric “on the margin” used to charge EVs is likely generated by coal and gas fueled power plants. If there is higher demand for electricity due to EVs, communities downwind from fossil fuel power plants could face higher levels of pollution that outweigh the reduction in tailpipe emissions. Furthermore, an electric vehicle in colder environments can emit more of the greenhouse gas CO2 than an equivalent gasoline car due to decreased battery efficiency in cold weather which requires more charging than in warmer weather. That said, EVs are typically less polluting than their ICE counterparts: a study published by Nature Sustainability in 2020 found that EVs are “less emission intensive” than fossil fuel–based alternatives in 53 world regions representing 95% of global transport.