Electric vehicles as grid resources: Barriers to vehicle-to-grid (V2G) in the United States

Growth in electric vehicle (EV) adoption has increased interest in using EV batteries as grid resources. Vehicle-to-Grid (V2G) technologies enable bidirectional power flows between electric vehicles and the electricity system and have demonstrated potential to support grid reliability and resilience in pilot programs worldwide. Despite demonstrated technical feasibility and system-level benefits for utility resource planning, broader V2G deployment remains limited. This study examines barriers to V2G adoption in the United States using qualitative evidence from 33 interviews with 42 stakeholders, including utilities, government agencies, original equipment manufacturers (OEMs), school districts, and participants in V2G pilot programs. We apply the Extended Unified Theory of Acceptance and Use of Technology (UTAUT2) as an organizing framework to examine adoption barriers across five constructs: facilitating conditions, effort expectancy, performance expectancy, price value, and social influence. Barriers related to facilitating conditions and effort expectancy emerge as the most salient, reflecting persistent challenges in standardization and interoperability across the V2G ecosystem, as well as concerns related to market development, infrastructure readiness, grid integration, and compatibility between vehicles and charging equipment. Performance expectancy follows, as stakeholders raise concerns about battery degradation, vehicle warranty implications, and vehicle availability in day-to-day operations. This study contributes to understanding barriers to V2G adoption and identifies policy-relevant pathways to reduce implementation challenges, including the development of interoperable standards and clearer institutional support.