A comparative analysis of in-motion and overnight charging infrastructure design for e-buses

With the increasing environmental concern due to using fossil fuels, there is a global trend towards large-scale vehicle electrification. This study examines a scenario where an urban area's current fleet of conventional fossil fuel buses will be replaced with electric buses (e-buses). The study compares two different charging strategies, in-motion charging (IMC) and overnight charging (ONC), for deploying a cost-optimal e-bus system on a city's sub-network to help operators make better decisions. The e-bus systems are designed using Mixed Integer Linear Programs for a sub-network of the real-life bus network in Delhi, India to demonstrate the usability of the study. The results indicated that the e-bus system designed using IMC was about 8 % more economical than charging the buses overnight. The main difference was observed in the charging infrastructure and the battery sizes selected for the e-buses. Using IMC, enabled the e-buses to complete the day's service with a significantly smaller sized battery compared to when the e-buses are charged overnight, leading to savings in cost and the yearly CO₂ emission due to the battery manufacturing process. Sensitivity analysis conducted for battery price trend in the future shows with decreasing battery cost ONC becomes a more economical option, although concerns regarding CO₂ emission remains. This study will help the transit operators and policy makers to make decisions regarding the kind of e-bus system to deploy considering the long-term cost and environmental factors of the same.