v2g

V2G, or vehicle-to-grid, refers to technologies and policies that allow electric vehicles to feed electricity back into the power grid or to local loads. In V2G, EVs equipped with bidirectional charging can discharge electricity from their batteries when needed and recharge when supply is abundant. This enables vehicles to act as mobile energy storage resources that can support grid operations.

Implementation requires bidirectional chargers, compatible vehicle batteries, and a communication protocol to coordinate with grid operators or aggregators. Protocols such as ISO 15118 enable two-way control and data exchange, and charging infrastructure can be managed to participate in services like frequency regulation, spinning reserve, peak shaving, and demand response. Aggregators may coordinate a fleet of vehicles to provide aggregated capacity to the grid.

Users participate through arrangements with utilities or energy service providers, potentially receiving compensation or reduced energy costs for allowing their vehicles to discharge during high-demand periods. While most pilots focus on fleets or parked vehicles, residential V2G concepts are also explored to support home energy management and local loads.

Challenges include the higher cost and availability of bidirectional chargers, concerns about battery degradation and efficiency losses, and safety considerations. Regulatory frameworks, market structures, and interoperability between vehicles, chargers, and grid systems vary by region. Cybersecurity and data privacy are also important considerations as V2G relies on networked control and monitoring.

Status and outlook: V2G remains largely in pilot and demonstration stages in many regions. Widespread commercial deployment depends on continued advances in technology, standardization, policy support, and viable business models that align grid needs with consumer benefits.