Technology assessment of an electric urban bus system for Berlin

Abstract

Public transport authorities particularly in conurbations and mega-cities undertake growing endeavours to improve their CO2 footprint and become less dependent on fossil fuels. Electric buses are an obvious alternative to conventional diesel vehicles. However, public transport authorities face several different options of electric bus technologies and different system solutions to implement electric buses. These options have specific assets and drawbacks concerning technology, capital and operational cost. Despite the importance of this issue only very limited research has been published on that matter so far. This study presents a technology assessment of battery-electric public bus systems based on technical and economical key performance indicators. The methodology is applied to an electric bus project for the city of Berlin. To facilitate the selection of a suitable technology a step-wise approach is applied. Firstly, an energetic simulation model has been set up to forecast the needed energy for daily service based on bus operating profiles in Berlin. Secondly, a pre-selection of potential electric bus solutions is made by qualitative evaluation of different systems using defined technical and economic indicators. Thirdly, a detailed comparison is made between the remaining technological alternatives taking monetary-based aspects into account. The economic analysis is conducted by means of a total cost of ownership (TCO) approach. In conclusion the examination reveals that under Berlin conditions inductive opportunity charging technology fulfills the comprehensive system’s requirements and shows relatively low TCO values.