Electric buses: lessons to be learnt from the Milton Keynes demonstration project

摘要

Electric buses deliver zero tailpipe emissions and have the potential to offer solutions to the air quality challenges of urban mobility in the 21st century. However, bus duty cycles are very demanding and unusually large batteries are required if electric buses are to have the range and ruggedness of their diesel counterparts. This research investigates an alternative strategy focusing on the performance of electric buses using wireless charging technology to provide opportunity charging during the working day without interrupting the timetable. In particular, the Milton Keynes demonstration project is analysed in an attempt to detect the factors that affect electric vehicles' functionality, and learn lessons retrospectively in terms of design considerations. Two different approaches are used to evaluate the performance of the eight buses which have taken over the Number 7 route at Milton Keynes since January. Firstly, an overall analysis of the buses has been conducted according to the ambient conditions, driver influence on the performance, vehicles' capabilities, vertical profile of the route as well as the driving and battery conditions. Additionally, the ground system's efficiency is analysed in order to correlate the energy drawn by the buses with the energy drawn from the network during the charging periods at the charging points. Considering the energy consumption and the system's efficiency, the actual performance of the buses and charging system is proven to be reasonably comparable to and consistent with the theoretical one while it is comfortably within the design base. This study raises important points for the crucial factors that affect electric vehicle's performance in a real life context and in a fully operational environment and could be the starting point towards proving that wireless charging is a significant game changer in terms of bus transport in the United Kingdom.