Assessing the impact of electric four-wheelers on the environment

Abstract

According to the United Nations Environment Programme (UNEP), the transportation sector contributes approximately one-quarter of all energy-related greenhouse gas emissions. The increasing use of personal vehicles (PVs), especially conventional fuel-based four-wheelers, is significantly worsening the air quality index (AQI). Furthermore, the COVID-19 pandemic, during which social distancing was promoted as a preventative measure, has increased the propensity of PV use. As such, efforts to decarbonise transport have to be emphasised, wherein the adoption of electric vehicles (EVs) could play a crucial role. It is worth mentioning that European Union has been the global frontrunner for EV adoption with about 20% of its new vehicle stock being electric, while India is bridging the gap fast with its respective EV share being nearly 11%.However, EVs per se might not be able to bring about changes in the existing scenario, as a substantial share of the electricity demand is met (for example, more than half of India’s production) through non-renewable energy sources. In such a situation, higher adoption of EVs would lead to increased demand for electricity, resulting in more emissions from thermal power plants, thus offsetting the reductions in tailpipe emissions. As such, this study analyses the environmental benefits of electrifying the passenger 4-wheeler transport sector by - (1) optimising the share of renewable energy sources (RES) and (2) facilitating higher shared usage of electric vehicles. While the existing studies largely focus on ownership and usage aspects of personal-use EVs, very few estimates the impact of the transition of different passenger commercial EV fleets and their emission implications for various RES utilisation. The present research aims to empirically assess demand for car-based travel alternatives (personal car, ride-hailing/ sharing, and taxi) while illustrating plausible electrification scenarios, considering emissions at sources. Such emissions are estimated through life cycle assessment (LCA) of vehicle operations and at power generation sources, i.e., thermal power plants. The current study considers vehicle level LCA including majorly three stages- (1) manufacturing, (2) operation, and (3) decommissioning-recycling, whereas the LCA at power generation sources was carried out at four stages- (1) upstream, (2) fuel cycle, (3) powerplant function and (4) downstream. This approach aids in developing a comparable emission estimate for EVs vis-à-vis conventional vehicles. At the same time, it presents a true view of EV’s emission reduction potential incorporating the RES transition effect.  Data regarding user behaviour and choice towards the aforementioned four-wheeler-based alternatives have been collected using questionnaire surveys in Kolkata, India, and a multinomial logit model is developed. Subsequently, the model is used to develop scenarios for estimating the likely effects of electrification on travel choices. Finally, the LCA method, including exergy analysis and battery degradation, is used to calculate the impact of such travel choices on energy use and decarbonisation. The study is expected to provide empirical evidence for the viability of EV deployment in India and the benefits of switching to EVs with an increased share of RES in power generation.Keywords: Electric vehicle (EV); Vehicular emissions; Lifecycle assessment (LCA); Renewable energy sources (RES)