Energy savings in public transport

Growing pollution levels and traffic congestion in major cities are becoming delicate issues that could be eased by more efficient public transportation systems. To reduce emissions, electric powered vehicles are in use in many cities. Depending on the number of commuters and on the available infrastructure, different types of electric vehicles (battery electric buses, trolley buses, trams, metro, light rail) can be applied. Although these mass transit vehicles enable large reductions in terms of emissions, their energy efficiency could be significantly improved. This improvement can be reached by the hybridization of their drive train with the inclusion of an energy storage system (ESS) for energy recovery purposes [1], [2]. Recent studies have shown that up to 40% of the energy supplied to electrical rail guided current, and power losses, a model of the tram, network, and substations power flow has been developed in a Matlab/ Simulink environment. Results obtained in energy savings at substation level vary from 24iquest27.6% under the same driving profile and auxiliaries load, while at the endof- life (EoL) of supercapacitors, the range varies from 18.1 - 25.1%, depending on the super capacitor module used and the vehicle load.