To limit global warming to below 1.5 °C, global efforts are being made towards decarbonisation of energy sources, among which UK has placed itself at the forefront to achieve net zero greenhouse gas emissions by 2050. Transport is responsible for 26% of total GHG emissions, of which light duty vehicles represent >50%. Battery electric vehicles (BEVs) are seen as a pathway to achieve decarbonisation and improved local air quality of future transport at the point of use. However, there are environmental concerns about the production of BEVs because of toxic substances released during mining activities and the reliance on critical elements. The degree to which the use of BEVs can contribute to decarbonisation also depends upon the percentage of renewable energy sources in the electricity grid mix. The increased electricity demand and a growing vehicle fleet will entail greater energy investment and resource requirements to meet future targets. Strategies such as the uptake of shared mobility, to minimize the number of vehicles on the road, and circularity of resources, could reduce the wastage of raw materials and associated environmental and energy impacts. Given that lithium-ion batteries (LIBs) play a vital role in both the energy transition of transportation and energy storage for the electricity sector, respectively by enabling the electrification of transportation and supporting the increase of renewables in the electricity mix, there will be an increase in demand for critical battery elements. Reusing batteries to support the electricity grid mix and recovering battery materials for reuse in BEVs could be opportunities to ease some of the environmental concerns. This thesis developed the case study of the entire passenger light-duty vehicle (LDV) fleet in the UK, set within the context of the co-evolution of transport and energy systems, up to the year 2050. The study investigates the environmental trade-offs of different BEV pathways by incorporating resource strategies, namely: the uptake of shared mobility, battery second life and closed-loop recycling. Initially, a systematic review of the sustainability supply challenges of battery cathode elements and other critical elements for supporting the low-carbon transition was conducted. To evaluate the consequences of resource strategies on the environment, a dynamic approach was taken to carry out a material flow analysis (MFA) and life cycle assessment (LCA) up to the year 2050. A dynamic MFA was used to track the changes in the mass flows of key chemical elements for each year, which laid the foundation for the LCA to assess the environmental consequence of the evolution of the whole UK LDV fleet over time. The interplay of several prospective changes were taken into consideration: (1) the transition of internal combustion engine vehicles (ICEVs) to BEVs, (2) the transition to a low-carbon electricity grid mix, (3) the improvement in LIB technology, (4) the uptake of transport as a service (TaaS). It was found that two strategies, namely recovering battery cathode materials and the successful uptake of TaaS, can play the most significant roles in reducing the overall demand for primary crtical materials for LIBs for both BEVs and grid-scale storage in the long term. Furthermore, second-life batteries were found to play a lesser role over time, due to the sheer requirement of battery elements by the BEV sector compared to grid storage battery requirements. In terms of environmental impact, the carbon emissions associated with the manufacturing of new BEVs are significantly higher than those for ICEVs. However, this is more than compensated by the positive effect of low-carbon electricity. Furthermore, the combined closed-loop recycling of cathode materials and potential emissions reduction due to TAAS also indicate a significant reduction potential in abiotic resource depletion and human toxicity potentials, whereas closed-loop recycling alone did not indicate the same outcome. Hence, this case study has highlighted the importance of applying both strategies synergistically to minimize the overall environmental impact of the transition to BEV for the passenger vehicle fleet.
Permanent link to this resource: https://doi.org/10.24384/9dvb-qb69
Kamran, Mashael
Supervisors: Raugei, Marco ; Hutchinson, Allan
School of Engineering, Computing and Mathematics
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