V2G needs interoperabilits – the quest for a unified and overall system architecture (UNPOSAR)

Vehicle-to-Grid (V2G) technology enables bidirectional energy flows between electric vehicles and the power system, supporting grid stability, renewable integration, and new value streams. Yet, large-scale deployment is hindered by fragmented system architectures and limited interoperability across technical and market domains. This paper presents a consolidated V2G architecture that integrates both behind-the-meter (BTM) and in-front-of-the-meter (ITM) perspectives into a unified framework. By synthesizing prior projects with different focus areas, the blueprint provides a holistic representation of roles, devices, and interfaces along the V2G chain. The results highlight how interfaces between EVs, charging infrastructure, energy management systems, and aggregators must align with standards such as ISO 15118, OCPP, and IEC 61850 to ensure scalable interoperability. Key findings show that standardization gaps remain, particularly for bidirectional use cases, semantic harmonization, and BTM-specific integration. Furthermore, reliable data with sufficient frequency, accuracy, and trustworthiness is essential for enabling V2G participation in flexibility markets. Developed within the BMWK-funded project InterBDL under the lead of IE2S, the consolidated blueprint is positioned as a living reference. Its upcoming publication for public consultation aims to validate and refine the model, thereby advancing the path toward interoperable and market-ready V2G solutions.