Environmental Evaluation of Battery Electric Vehicles: Integration of Life Cycle Assessment and Circular Economy

基於循環經濟及生命週期評價相結合的純電動汽車環境影響評估

Student thesis: Doctoral Thesis

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Detail(s)

Awarding Institution
Supervisors/Advisors
Award date2 Sep 2021

Abstract

The transportation and electricity sectors are in the midst of leading changes in the endeavor to mitigate climate change and air pollution issues. In future years, traditional fossil-fuelled vehicles are estimated to be substituted with battery electric vehicles (BEVs), resulting in higher electricity demand from the transport sector. Meanwhile, the electricity sector is transforming due to policies to adopt renewable energy resources such as solar, wind, and hydropower in the future. However, there are still societal concerns regarding the environmental benefits of these vehicle technologies and how new energy options and vehicles will benefit in the future. Moreover, with an increase of electric vehicles, the use of BEVs lithium-ion batteries (LIBs) is anticipated to grow, which further increasing the demand for LIBs materials. With the increase in the number of BEV batteries, the number of batteries from BEVs reaching their end-of-life (EOL) will proliferate soon. There is a need to understand the EOL implications of retired LIBs from BEVs in the coming years. To address these concerns, this research aims to analyze the environmental burdens of current and future vehicles using the Life Cycle Assessment (LCA) and fostering a circular economy for a material flow analysis of end-of-life LIBs from battery electric vehicles (BEVs).

Firstly, this research evaluated the environmental impact of battery electric vehicles (BEVs) production and highlighted the future implication of usage of these BEVs during their lifetime. A comparative life cycle analysis was performed in the top 10 electric vehicle selling countries in their current and future electricity mix scenarios. The results revealed that BEVs in China with current (2019) energy mix scenario showed a higher impact of global warming than all other BEVs from other selected countries. In contrast, BEV 2030 Norway was found to be an optimal choice and has the least environmental impact in most of the selected categories. Besides, it was also found that all BEVs with the 2030 electricity mix had lower environmental damages than the BEV 2019 electricity mix.

Secondly, Hong Kong was selected as a case study to comprehensively evaluate the environmental burdens of current (2019) and future (2050) vehicles. The LCA was performed for internal combustion vehicles (ICEV) fueled with diesel and petrol, Plug-in hybrid vehicles (PHEV) and BEV with future electricity energy mix scenarios (2019-2050). The results revealed that electric vehicles with the 2050 electricity mix are optimal and have the least environmental impact in most of the selected impact categories. Plug-in hybrid vehicle with diesel was the second optimal choice to reduce the environmental impacts in the current scenario. Besides, this study outcome indicated that the use of clean energy could help to decrease the environmental impact and mitigate climate change in Hong Kong.

Thirdly, the LIBs are considered one of the major components of BEV and significantly contribute to the overall environmental performance of BEV. Moreover, it includes multiple materials which required careful handling after their usage. Therefore, this research evaluated the end-of-life of used BEV LIBs most widely used battery, such as lithium nickel manganese cobalt oxide (NMC), on a global scale. For this purpose, the global sales data of NMC batteries from 2009 to 2018 was collected, and the sales data from 2019 to 2030 was estimated based on the historical trend and BEV development plans around the globe. Moreover, this study also estimates future LIBs demand in the USA and China and its influences on the materials demand, EOL reaching of LIBs material, and second use based on three different scenarios. The estimated results show that China would require almost two times more materials than the USA to meet the future LIBs demand. In addition, the results showed that in 2030 there would be around 5-7 kt of recovered Li, 35-60 kt of recovered Ni only in China. Based on the economic evaluation of LIBs in scenario 2, it was found that recovered nickel would have the economic values of 725 million US dollars only in 2030 in China. Through the second use assessment of LIBs in the third scenario, where 50% of used batteries were assumed for second use application, it was found that around 33 GWh batteries would be available for second use only in 2030 in China. Therefore, the larger portion of used LIBs should be utilized for a second life as it could further delay the recycling of LIBs, which can further give time to the government so that the improved and larger recycling infrastructure could be built to tackle a higher amount of coming used LIBs.

In summary, this research evaluates the environmental performance of electric vehicles through the integration of LCA and circular economy in current and future scenarios. It provides a comprehensive evaluation of BEV with various future energy scenarios that will let the decision-maker choose sustainable mobility. Moreover, it is also expected to help the government to inform energy policymakers regarding the energy transition. Furthermore, the outcomes of this research advocate the community in mitigating their transport-based carbon footprint and growing the low-emission travel culture for a sustainable future.

    Research areas

  • electric vehicles, battery electric vehicles, plug-in hybrid electric vehicle, life cycle assessment, internal combustion engine vehicle, sustainability, lithium nickel manganese cobalt oxide, Stanford method, Weibull distribution, global warming potential, environmental impact assessment, greenhouse gas emission, use phase, lithium-ion batteries, end-of-life, recycling, economic assessment, material flow analysis, functional unit, system boundary, cradle to grave