Buses are an integral part of urban public transport systems. However, urban buses are responsible for about 8% of the road transport Green House Gas emissions in EU [8]. Buses with internal combustion engines are responsible also for emissions of fossil carbon dioxide (CO2) as well as air pollutants particulate matter (PM) or nitrogen oxides (NOx). Thus, zero emission buses, have a significant potential in the reduction of transport related emissions in urban areas.
Zero emission buses use an electric motor with batteries or fuel-cell with hydrogen tank for propulsion. Electric buses use an electric propulsion motor and the energy is provided either by batteries (Battery electric vehicles, BEV) and also, mainly in older installations by overhead wires (trolleybus) or inductive systems embedded in the road. The battery trolleybus is a less used solution that can still use overhead wires for propulsion but can ride independently, on a part of its route which is not equipped with wires using a battery [2]. Different charging technologies are available for electric buses: manual plug-in connection and automatic connections, like pantograph-type connections from the top or the bottom of the vehicle [3]. Moreover, different BEV charging approaches can be used, including overnight depot charging, alone or supported by opportunity charging (e.g. at the end of the line or at stops) during the daily use.
Fuel-cell electric buses contain a hydrogen tank, and the fuel cell which converts hydrogen into electricity then supplied to the electric motor, directly or after being stored into the on-board battery. Fuel cell provides all of the energy for the vehicle, while batteries offer peak power for the motor during the acceleration and regenerative braking phases. [4].
The European Clean Bus Platform offers E-Bus Decision Support Toolkit [6] and the Operators’ guide to fuel cell bus deployment [5] developed by the JIVE project for HFC buses bring together European cities, transport authorities and operators to share experience, exchange of knowledge and support deployment of zero emission buses.
Figure 5: Overview of different technical charging solutions A (plug in), B (pantograph going down), C (pantograph going up) and D (pantograph below vehicle), (Source UITP, April 2018)
The European Commission’s software tool VECTO, can be used to calculate the energy consumption and range, to support the purchasing process of new buses [11].
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