Public transportation with electric traction: Experiences and challenges in an Andean city

Abstract

The paper studies the energy behavior of a battery-electric bus (BEB) operating on commercial routes as well as the technical feasibility of a total replacement of the current public transport fleet by BEBs in an Andean city. The electrical variables in the BEB charging process are evaluated obtaining THD current distortions of less than 4%, values that meet national and international standards. Regarding the energy demand, the study uses an estimate that allows quantifying the energy consumption of the fleet of 424 BEBsthat would operate the 28 routes. It is estimated that the maximum demand during the charging process can reach 33.92 MW if the fleet is charged at a rate of 80 kW per BEB and 19.96 MW if the charge is at 40 kW, whereas the charging time can range from 4 h to 9 h, respectively. The daily energy needed to power the fleet is 115 MWh, which represents about 4% of energy demanded per day by the city. The estimation of the energy efficiency of the BEB under analysis presents values that vary between 0.67 and 0.94 km/kWh, an indicator that depends on the conditions of the route. The article includes and study on the preference of BEB users as compared to conventional buses. Finally, the study shows a feasible alternative to integrate renewable energy sources for BEB charging, based on photovoltaic solar generation and the use of energy storage systems, as a contribution to the sustainability of the public transport.