Mitigating carbon emissions in the taxi service industry: a comprehensive Life Cycle Assessment of batteries for electric taxis and identification of a greener vehicle fleet

PurposeThe aim of this study is intended as decision support tool for taxi service industry to identify the most suitable vehicle segment for electric taxis (e-taxi), focusing on B- and C-segment vehicles, which constitute the standard fleet for taxi services. To this end, a comparative Life Cycle Assessment (LCA) of e-taxi vehicle batteries is conducted. This assessment incorporates a novel method for quantifying hourly environmental impacts during the battery charging phase. It simulates a typical workday for an e-taxi equipped with digital technologies capable of sharing grid electricity consumptions with online services. These services, in turn, provide carbon intensity values based on regional average electricity emissions, with hourly resolution.MethodsAssuming B- and C-segment e-taxis differ only on battery capacities, energy consumptions, and battery aging constraints, it has been possible to choose the vehicle battery as the unit process of the comparative analysis. The cradle-to-grave LCA is adopted. The GWP is calculated according to the functional unit of 1 km traveled by the e-taxi. Finally, a sensitivity analysis of the e-taxi daily distance and taxi service life with respect to the Base Case scenario is performed, which considers average values equal to 200 km/day and 10 years, respectively.Results and discussionIn the Base Case scenario, B-segment and C-segment involve a GWP of 49.3 and 54.6 gCO2eq/km, respectively, with C-segment having a 10.8% higher GWP than B-segment. The use phase dominates GWP impact for both segments, followed by manufacturing and end-of-life phases. The hourly emissions during the use phase were simulated, revealing increased GWP during the night, influenced by a higher charging probability and an unfavorable electricity mix. The sensitivity analysis highlights that B-segment has a higher GWP than C-segment for specific ranges of daily distances and e-taxi service life. This is due to an accelerated battery aging in the smaller vehicle segment and earlier battery replacement. Consequently, there is an addition of supplementary emissions resulting from manufacturing and EoL of extra batteries.ConclusionsThe study contributes to our understanding of the importance of manufacturing and EoL stages of batteries in terms of environmental impacts. These elements can result in interesting conclusions, highlighting how smaller electric vehicles with lower energy consumption may have higher environmental impacts due to accelerated battery aging and the consequent need for additional batteries during their lifecycle.