In this paper, the change of fossil energy consumption, carbon dioxide (CO2) and pollutant emissions are calculated when petroleum based vehicles (PBVs) are taken place by EVs based upon the full-cycle energy efficiency theory with the energy efficiency measured from "well to wheel.". Calculation results show that the fossil energy consumption, CO2, monoxide (CO) and hydrocarbon (HC) emissions can be reduced with the substitution of EVs for vehicles that burn gasoline (GVs), but nitrogen oxides (NOx) and sulfur dioxide (SO2) emissions increase. When vehicles that burn diesel (DVs) are replaced by EVs, the emissions of pollutants except SO2 will be reduced, but the emissions of CO2 and SO2 will increase. Considering the proportion of coal-fired power generation to the total power generation in China, the goal of energy conservation and emission reduction cannot be perfectly achieved by the substitution of PBVs by EVs. Therefore, the proportion of clean energy generation should be increased in China and technological updating of coal-fired power plants for reducing CO2 and pollutant emissions are necessary as well. Besides, GVs, other than DVs, should be replaced by EVs from the perspective of energy conservation and CO2 emission.
