Sustainability evaluation of an electric bus fleet for the urban public transport system of Padova, Italy

The paper analyses the potential benefits deriving from the introduction of an electric battery-supplied bus (EBB) fleet in the urban transportation context of the city of Padova. Such analysis is carried out in the frame of a business plan focused on the development of recharge/replacement stations located at suitable bus terminals, adopting an optimized strategy to replace and recharge the on-board batteries running low. After an extensive analysis of the actual urban bus fleet, equivalent bus configurations are defined for both diesel and compressed natural gas vehicles, by means of an analytical elaboration of reference driving cycles. Such elaboration also includes the performance deterioration over the vehicle life by applying a derating function to the propulsion system and catalyser efficiencies. Then, the EBBs characteristics and operation are determined by an algorithm aiming at the minimization of the battery investment and operating costs on a ten years service. Finally, the equivalent buses with different lengthare compared in terms of energy consumptions and pollutant emissions on the same reference routes. Such comparison is carried out by numerical simulations, taking into account both the engine practicalbehaviour and the battery charge/discharge operation.