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Assessment of diesel and electric buses under different routes features: A case study at the Living Lab of the University of Campinas

Abstract:

Electric buses (ebuses) have been recognized as an important alternative in public transportation to reduce the environmental impacts of fossil fuels and increase energy efficiency. Its operating costs are cheaper compared to diesel buses. However, their purchase prices are not yet competitive, which is a barrier. Concerned with the environmental issues, public administration in major cities around the world are developing programs to break this barrier, in which important aspects are the financial incentives and the implementation of a minimum number of routes by means of non-polluting buses. In order to comply these planes, it would be relevant the appliance of a method to find the better routes, in which the ebuses could be even more energy-efficient and could get better financial returns, taking into account the speed, topography, number of passengers and the usage of regenerative brake system (RBS). For that, this paper presents replicable simulations models to choose the best routes where ebuses could be more competitive. The analysis is made from tracking GPS coordinates from regular bus routes on the campus of the State University of Campinas (Unicamp), which allow the extraction of altitude, average speed and trace position. Also, it estimates losses in the buses, as rolling resistance, aerodynamic drag, powertrain efficiency and limitations on the RBS. As result, the models present the total necessary energy for the route operations from ebuses and diesel buses, the gain of energy efficiency and energy costs for ebus according to the features of the routes and finally, the selection of the best routes for ebuses. It has gotten that the best advantages of the ebuses are in the routes with high average slope and low average speed, in which there is many acceleration and deceleration cycles, commons in city centers.