Whole-system Potential and Benefit of Energy Storage by Vehicle-to-grid (V2G) under Carbon Neutrality Target in China

Due to high penetration of renewable energy, the new electricity system oriented to carbon neutrality will face the bottleneck of insufficient flexibility resource. Electric vehicle (EV) shall become a core hub of energy consumption and storage. This paper proposes a coupled transportation-energy-electricity framework to evaluate the technical potential and whole-system value of smart orderly charging and vehicle-to-grid (V2G) in China. This approach simultaneously optimizes power supply installation, transmission network, storage capacity, as well as unit commitment, power dispatch and system reliability for real-time nationwide energy balancing, while considering EV ownership development, travel behavior and charging demand. Scenarios of unmanaged charging, smart charging and V2G are carried out for cases of 2025, 2030, 2040, 2050 and 2060. Results show that, in 2040, the total installed energy of EV batteries will be over 20 TWh and the flexible adjustment capacity exceeds 10 TWh. The V2G operation can reduce up to 730 Mt CO2 emission annually. The levelized whole-system cost for low-carbon transformation can be declined by up to 49.7% till 2060 under V2G scenario compared with unmanaged charging. Considering thermal power freely developing as business-as-usual case, the unit decarbonization cost could even be reduced by 100.2% to be minus through V2G integration in 2050.