A gasoline powered car turns about 75% of the energy you buy into waste heat. Electric cars are much more efficient - something like 20% of the energy is lost at the car (ignoring the efficiency of gasoline and electricity production). The concentration of cars in cities can be high enough to raise the temperature - on warm days that can increase cooling costs.
In a paper published in Nature's Science Reports the impact of moving from internal combustion to electric cars is studied to Beijing. (of course you do better moving to even more efficient transit - public transit and cycling)
Hidden Benefits of Electric Vehicles for Addressing Climate Change
Canbing Li1,2, Yijia Cao1, Mi Zhang1, Jianhui Wang1,3, Jianguo Liu2, Haiqing Shi1 & Yinghui Geng1
1College of Electrical and Information Engineering, Hunan University, Changsha 410082, China,
2Centre for Systems Integration and Sustainability, Michigan State University, RM 115, S. Harrison RD, East Lansing, MI, 48823, USA,
3Centre for Energy, Environmental and Economic Systems Analysis, Argonne National Laboratory, 9700 S. Cass Avenue, Bldg. 221Argonne, IL 60439, USA.
There is an increasingly hot debate on whether the replacement of conventional vehicles (CVs) by electric vehicles (EVs) should be delayed or accelerated since EVs require higher cost and cause more pollution than CVs in the manufacturing process. Here we reveal two hidden benefits of EVs for addressing climate change to support the imperative acceleration of replacing CVs with EVs. As EVs emit much less heat than CVs within the same mileage, the replacement can mitigate urban heat island effect (UHIE) to reduce the energy consumption of air conditioners, benefitting local and global climates. To demonstrate these effects brought by the replacement of CVs by EVs, we take Beijing, China, as an example. EVs emit only 19.8% of the total heat emitted by CVs per mile. The replacement of CVs by EVs in 2012 could have mitigated the summer heat island intensity (HII) by about 0.946C, reduced the amount of electricity consumed daily by air conditioners in buildings by 14.44 million kilowatt-hours (kWh), and reduced daily CO2 emissions by 10,686 tonnes.