The rapid penetration of plug-in electric vehicles (PEVs) and charging infrastructure entails the need of harnessing PEVs’ load flexibility and storage capacity to friendly integrate into the grid system. Through Vehicle Grid Integration (VGI) measures—managed charging and Vehicle-to-Grid(V2G), PEVs can be conducive to balancing the electricity system, reducing costly grid upgrade, and supporting large renewable integration.
However, one of the primary technological barriers to implement VGI in China is the lack of open and interoperable communication protocols among PEVs, Electric Vehicle Charging Stations (EVSE), Charging Point Operators (CPO)/aggregators, and utilities (like Distribution Service Operators, DSO) that enable VGI. Based on the investigation of the prevailing international and domestic communication protocols (including open and proprietary ones) used in VGI pilots, this study unravels that China’s current PEV-EVSE standard (GB/T 27930) doesn’t support VGI, EVSE-CPO and CPO-DSO protocols are mainly proprietary with the absence of VGI functionality, all the protocols have weak cybersecurity protection.
With the large roll-out of charging infrastructure investments as a part of the “New Infrastructure” stimulus plan, charging facilities will not only grow in quantities, but also become smarter and interoperable. To avoid stranded asset dilemma and expensive hardware updates, and to create a leveling playground for charging facilities, the study recommends:
- Step up the standardization process for the hierarchy of VGI-capable protocols, including amendments on the PEV-EVSE standard (GB/T 27930), expansionof the functionalities and the adoption of the open EVSE-CPO protocol (T/CEC 102), the standardization of the CPO-DSO protocol, and the development of standard VGI use cases based on the trove of VGI pilots (also underscoring the needs to explore diverse VGI business models and use cases) as well as the systematic enhancement of the cybersecurity measures. The protocols should also be updated or developed with sufficient “backward compatibility” and clarity to avoid interoperability conflicts.
- Ensure the widespread adoption of the hierarchy of VGI-capable protocols, including revisions on the conformance testing protocols, consideration of official certification of products compliant with the protocols, and the openness of distribution data by utilities.