V2G is an advanced form of bidirectional charging, specifically referring to the energy interaction between EVs and the public power grid. It is not just simple discharging but involves real-time communication between the vehicle and the grid dispatch center. Under grid instructions, vehicles act as distributed storage units participating in ancillary services like frequency regulation and spinning reserve, earning financial returns for doing so.

Analysis from an Application Environment Perspective

V2G application environments require mature electricity trading market mechanisms and vehicle resources that are parked for long durations.

• Virtual Power Plant (VPP):
  Aggregators connect thousands of scattered EVs in homes or parking lots. In moments when wind generation drops suddenly, these vehicles collectively feed power to the grid within seconds, replacing natural gas peaker plants. In this environment, V2G is a cornerstone of grid resilience.
• School Buses & Municipal Fleets:
  Electric school buses have fixed schedules (morning/afternoon runs, long idle times in between and during summer breaks). This makes them perfect V2G assets. During summer idle periods, the bus fleet transforms into a massive megawatt-scale storage station, helping cities cope with peak summer AC loads and earning revenue for schools to subsidize vehicle costs.