The use cases described here identify the equipment (system elements) and interactions to support grid-optimized AC or DC energy transfer for plug-in vehicles, as described in SAE J2847. Key system elements include the vehicle’s rechargeable energy storage system (RESS), power conversion equipment (charger and/or inverter), utility meter, optional advisory sub-meter (EUMD), load management system (LMS), and equipment for control, monitoring, and communication. System elements may be optionally packaged in various ways (either separately or in combination) to deliver implementations tailored to a given environment, such as a residential, public or commercial charging location. Implementations may also vary in relation to the vehicle itself. The charger and charging control technology each may reside either on-board or off-board the vehicle; for example, off-board control may be implemented as a ‘smart plug’.
Use cases are technology-neutral, leaving implementers free to choose technological solutions appropriate to specific scenarios. For example, depending upon the situation, communication may occur via local wireless (ZigBee, Wi-Fi, etc.), power-line carrier (e.g., HomePlug PLC), vehicle telematics, long-range wireless (GSM, CDMA, WiMax, etc.), Internet protocols, or a combination of these methods.