Electric vehicle transformation in Beijing and the comparative eco-environmental impacts: A case study of electric and gasoline powered taxis

Abstract

Tailpipe emissions of gasoline vehicles are one of a main cause of atmospheric environmental problems such as global warming and haze. The substitution of electric vehicles for conventional gasoline vehicles is a promising new way to reduce urban air pollution in many countries such as America, Japan, the EU countries and China. In 2011, Beijing launched a plan that was the substitution of electric vehicles (such as Midi taxis) for gasoline vehicles (such as Hyundai taxis) to low carbon transformations. Our study used local data and LCA based analysis to compare environmental impacts of the transition from Hyundai gasoline vehicles to Midi electric vehicles. We established a life cycle analysis (LCA) model with GaBi6 software and a life cycle assessment integrated model by CML2001 (Problem oriented) and EI99 (Damage oriented) models, which evaluated the comparative environmental impacts of the full life cycle, production stage, use stage and end of life. Finally, we analyzed the key haze-induced factors, key life cycle processes and the sensitivities of lifetime and electric power mix.Our results indicated that in light of the full life cycle assessment, electric vehicles could play significant role in decreasing the potential of Global Warming, Abiotic Depletion and Ozone Layer Depletion; whereas, electric vehicles also exhibited the impacts for increases in the potential of Acidification, Eutrophication, Human Toxicity and Eco-toxicity (marine aquatic and terrestrial). On the basis of inventory data analysis and 2010 Beijing electricity mix, the comparative results of haze-induced pollutants emissions showed that the full life cycle emission of VOCs from a Midi electric vehicle was lower than a Hyundai gasoline vehicle, but the emissions of PM2.5, NOx, SOx of a Midi electric vehicle were higher than a Hyundai gasoline vehicle. These differences are mainly the result of different emissions during the use stages. In addition, the results of sensitivity analysis indicated that the decreased rate of Green House Gas per kilometer (Midi relative to Hyundai) gradually improved with the increase of lifetime and use of cleaner energy; haze-induced pollutants and carbon emissions from EVs could be reduced significantly with the increased use of cleaner energy.