| The rapid growth of vehicle ownership has led to a shortage of petroleum energy and serious environmental problems.Choosing coal-based alternatives vehicle fuels in regions or countries rich in coal resources can not only improve energy security,but also enable clean use of coal.However,coal-based alternative vehicle fuel pathways face environmental challenges such as energy consumption and carbon emissions.From the perspective of life cycle,this paper uses energy efficiency,carbon emissions,water footprint,and environmental categories as analysis indicators to comprehensively evaluate the advantages and disadvantages of coal-based diesel,coal-based natural gas,coal-based hydrogen,and coal-based power pathways.And scenario analysis is used to predict whether China,the United States,Japan,the European Union,the United Kingdom and Norway will adjust their vehicle fuel structure to achieve energy saving and emission reduction in 2030.Research indicates:(1)The energy efficiency of conventional petroleum-based gasoline fuel pathway is higher than that of coal-based alternative vehicle fuel pathways.At the same time,the conventional petroleum-based gasoline fuel pathway has a higher energy consumption.Among the coal-based alternative vehicle fuel pathways,the coal-based natural gas fuel pathway has a higher energy efficiency of 59.56%,and the coal-based electricity pathway has a low energy efficiency of 37.05%.(2)The carbon emissions of coal-based diesel,coal-based natural gas,coal-based hydrogen,and coal-based electricity pathways are 159.81kg/100km、101.71kg/100km、51.27kg/100 km 和 75.60kg/100 km,respectively.The coal-based hydrogen fuel pathway captures and utilizes carbon dioxide in the production stage,resulting in the best carbon emission reduction benefits.The carbon emissions of the remaining coalbased fuel pathways are higher than those of conventional petroleum-based gasoline fuel pathway.In addition,carbon emissions from various fuel pathways mainly come from the fuel production stage,and direct emissions dominate.(3)The life cycle water footprint of coal-based diesel,coal-based natural gas,coalbased hydrogen,and coal-based electricity pathways are 855.53kg/100 km,685.44kg/100 km,709.23kg/100 km,and 337.56kg/100 km,respectively,while the water footprint of the petroleum-based gasoline pathway is 281.2kg/100 km,which indicates that the coal-based alternative vehicle fuel pathways consume more water resources than the petroleum-based gasoline fuel pathway.Sensitivity analysis of the water footprint shows that reducing the water footprint of coal-based alternative vehicle fuels can be achieved by reducing direct water consumption and increasing disposal of pollutants with larger impact factors in wastewater.(4)The results of various mid-point environmental impact categories show that the coal-based diesel fuel pathway has a higher impact on all impact categories than the coal-based hydrogen fuel pathway,while the coal-based natural gas fuel pathway has a lower contribution to the impact categories.Nevertheless,coal-based natural gas has a greater impact on respiration organics,radiation,and ozone depletion.In terms of the environmental impact categories of the end-point,the coal-based alternative vehicle fuel pathways are more harmful to human health,followed by the impact on the quality of ecosystems and resources.The end-point impact categories of the coal-based diesel fuel pathway is almost double that of the other three coal-based alternative vehicle fuel pathways.The end-point impact categories of coal-based hydrogen,coal-based natural gas,and coal-based electricity pathways are similar,which are 2.91 Pt,2.67 Pt,and 2.31 Pt,respectively.(5)According to the scenario analysis shows that the United States and the European Union can significantly save energy and water resources and reduce GHG emissions with the increase in the proportion of new energy vehicle in 2030.However,even a complete ban on the use of conventional gasoline vehicle in Norway will not reduce water consumption.Since China and Japan have a small number of natural gas and diesel vehicle,GHG reduction are not ideal. |
