Spatio-temporal Flexibility Evaluation of Electric Taxi Fleets Using Taxi Travel Data in Beijing

With the increase in the penetration rate of electric vehicles, electric taxis in cities can play their inherent flexibility by discharging to support the operation of the power grid. Based on the real travel trajectory records of fuel taxis in Beijing, this paper proposes a state-based evaluation method for the spatiotemporal distribution of flexibility of electric taxi fleet. Firstly, the state transition relationship between electric taxis including four main states and seven transitional states is analyzed, and the number of flexible taxis at each time point is calculated. Considering the state transition relationship and users' mileage anxiety, an optimization model for evaluating the flexibility of taxi fleet is established. By solving the model, the upper and lower bounds of the battery energy range of the flexible taxis are obtained. The case studies analyze the flexibility of taxi fleet in different areas of Beijing based on real data, and indicates that there is promising potential for crossregional scheduling of taxis to reallocate flexibility in order to participate in demand response.