基于生命周期的新能源汽车碳足迹评价

Carbon Footprint Evaluation of New Energy Vehicles Based on Life Cycle

发展新能源汽车是实现碳达峰与碳中和目标的重要途径,而在现有技术和能源结构下,探讨新能源汽车的节能减排效果已成为研究热点。本文在梳理新能源汽车发展趋势的基础上,汇总了碳达峰与碳中和目标对新能源汽车提出的新要求,总结了生命周期评价法的定义、分类与特点,指出了该方法在追踪新能源汽车碳足迹中的重要作用,进而从新能源汽车和燃油汽车对比、典型国家新能源汽车环境影响评价两个角度,综述了生命周期评价法在新能源汽车领域中的运用及评价结果。最后,本文对新能源汽车生命周期评价的研究方向进行了展望,并提出了若干政策启示。

With the increasingly severe environmental problems such as climate change, serious urban pollution and shortage of fossil fuels, all countries are eager to find a technical path to replace traditional fuel vehicles to reduce the use of petrochemical resources and carbon emissions. In this context, the new energy vehicle industry embraces development opportunities. Some countries have set goals for new energy vehicles and launched a series of market promotion plans.Despite the general view that new energy vehicles are a feasible way to reduce dependence on oil and carbon dioxide emissions and to achieve zero emissions in the city center, are new energy vehicles really low-carbon and environmentally friendly? It is necessary to take the whole life cycle of new energy vehicles as the research object, use life cycle assessment to track the carbon footprint of new energy vehicles, and comprehensively evaluate the direct and potential environmental impact, so as to avoid the problem of environmental burden transfer.Based on the background of countries achieving carbon peak and carbon neutrality, this paper analyzes the role of new energy vehicles in this goal, and details the progress of research on new energy vehicles carbon footprint by means of the life cycle assessment. In comparing the environmental and ecological characteristics of different vehicle drive technologies, it is concluded that if non-fossil energy is used for electricity and hydrogen production, the promotion and use of electric vehicles can effectively alleviate climate change. However, given the dependence on coal-fired electricity, electric vehicles show a trend of increasing sulfide emissions compared to internal combustion engine vehicles. Even in terms of environmental burdens such as acidification, particulate matter formation and toxicity,electric vehicles may perform worse than high-efficiency internal combustion engine vehicles. According to the results of the life cycle impact assessment, among the indicators of climate change, fuel consumption and cumulative energy demand, the plug-in hybrid electric vehicle boasts the lowest value, followed by the plug-in hybrid fuel cell vehicle and pure electric vehicle, and the traditional fuel vehicle ranks the last. In research on the development of new energy vehicles in typical countries and regions, it is found that in China, the power generation structure is still dominated by coal power, and battery production and scrap processing are highly polluting, which hinders the environmental benefits of new energy vehicles. In the United States, widespread adoption of electric vehicles is not an optimal strategy given the current mix of marginal power generation costs. Instead, hybrid vehicles are the most energy-efficient option in all states.In Europe, there is a need to reduce the environmental impact of electric vehicle production supply chains and promote clean sources of electricity in electricity infrastructure. In South Korea, the market segments for electric and fuel cell vehicles need to be identified and infrastructure investments should be optimized, so as to promote the adoption of environmentally friendly vehicles. In Japan, the advantages and disadvantages of implementing emerging fuel cell technologies should be carefully discussed.It can be seen from the relevant combing and analysis that when fossil, mineral and metal resources are comprehensively assessed for non-biological resource consumption, due to the large environmental impact of fossil fuels in the entire life cycle of internal combustion engine vehicles, electric vehicles are more advantageous in reduction of resource consumption and carbon emissions. However, if the use period of electric vehicles is very short, or the recycling rate is very low, the negative impact of electric vehicles on the environment is not small. In addition, if the power structure of a country or region centers on coal and thermal power, the use of pure electric vehicles in that country or region is not the environmentally optimal choice.