Conversion of metro railway into smart charging zero-emission transportation hub for supporting electric train, shuttle bus, cars and public EV charging station

The unprecedented electrification of the transportation sector and rapid renewable energy penetration create multiple issues on available grid networks. Large-scale integration of various electric vehicle (EV) types into a distributed renewable energy system has not been studied before, and their systematic integration method and quantitative impacts are still unclear in academia. Therefore, this project converted an existing net-zero metro railway network into a smart charging EV hub by transforming the stations to smartly charge all types of EV intersecting at a station, such as public EV charging stations, electric shuttle buses and metro-owned EV cars. Accordingly, the methodology begins with the multiobjective analyses of integrating a public EV charging station into a swappable battery-powered metro station. Secondly, an electric shuttle bus is integrated into the stations without and with bidirectional energy sharing and evaluated for the impact of driving patterns, parking time, and schedule coordination. Thirdly, the metro-owned EV cars are incorporated into the stations and analysed for the number of journeys without and with bidirectional energy sharing. Finally, the importance of control priority while designing the smart charging EV hub is examined. Overall, converting a metro railway into a smart charging EV hub significantly increases the renewable energy consumption from 0.58 to 0.76, improves the net present value from 71.35 × 10⁶ HKD to –35.02 × 10⁶ HKD, and reduces the annual maximum grid import from 1099 kW to 777 kW. The success of vehicle-to-building energy sharing mainly depends on the driving demand ratio to the battery size.