Optimization of charging infrastructure for electric Taxis

For the transportation sector, electromobility presents a chance both to abolish oil dependency and to open the possibility of using sustainable energy sources. In the case of taxis, the substitution of electric vehicles for conventional vehicles with an internal combustion engine may be especially favorable because the driving patterns involve several waiting periods, which can be used for recharging the battery. An infrastructure consisting of charging stations at taxi stands needs to be developed to ensure the energy supply of these taxis. Designing a charging infrastructure requires the development of an optimization method to maximize the economic benefit of the whole system, consisting of electric taxis (e-taxis) and charging stations (CSs). The number of charging stations should be kept as minimal as possible to reduce costs. Simultaneously, the energy supply for these taxis has to be ensured to enable high mileage and earnings. This study introduces an event-based simulation of the e-taxis' mileage and an economic analysis that evaluates the benefit of possible configurations of numbers of e-taxis and numbers of CSs per taxi stand. Because the number of possible confgurations is high, an optimization algorithm is presented to reduce the calculation time and to find configurations with the highest economic efficiency. One result of the infrastructure optimization indicates that 445 CSs would be economically ideal for a taxi fleet in Munich, Germany, with 3,402 vehicles with a battery capacity of 20 kW-h.