A team of researchers led by Canbing Li from Michigan State University has published a paper showing that replacing conventional cars with electric ones could, not only cut emissions from the cars, but it could also lower emissions of carbon dioxide by cutting the use of air conditioning.
The team took Beijing in 2012 as an example. In the summer of 2012 in Beijing, the daily heat emitted by conventional vehicles was 9.85 × 1014 Joules. On average, electric vehicles emit 19.8% less heat than conventional vehicles. After allowing for an increase in the amount of heat emitted by power plants providing electricity for the electric vehicles, the researchers concluded that the net effect would be a decrease of 0.94°C in temperature.
This lower temperature would mean less use of air conditioning and, consequently, lower energy consumption. The amount of energy that could be saved each day by reduced building air conditioning use was estimated to be 14.44 million kilowatt hours. This would reduce carbon dioxide emissions by 10,686 tonnes per day.
The researchers pointed out their estimate is conservative because it did not take into account reduced air conditioning use in vehicles. The study also omitted the effect of reduced aerosol emissions from electric vehicles because different models have shown different effects.