V2G in OCPP 2.1 (and OCPP 1.6)

Vehicle to grid (V2G or V2X) refers to the concept of EVs being able to discharge. OCPP 1.6 and OCPP 2.0.1 don’t support discharging EVs natively.

ISO 15118 is a communication standard between EVs an chargers. ISO 15118-20 has been released in April 2022 as successor of ISO 15118-2. ISO 15118-20 adds support for discharging using AC and DC, among other things.

The Open Charge Alliance (OCA) has setup the V2X Task Group to add support for ISO 15118-20. These changes will be released as version 2.1.

The specification has been finalized, but not released. A public draft is to be expected in Q4 2023.

Changes compared to OCPP 2.0.1

This sections is based on v0.32 of the draft. While writing (2023-06-14), the latest draft is v0.40 out and details might have changed.

The V2X working group is writing an RFC to add V2X to OCPP.

These message will be added to OCPP 2.1 to support V2X:

• ModifyChargingProfile

• NotifyAllowedEnergyTransfer

• NotifyPriorityCharging

• PullChargingProfile

• UsePriorityCharging

The following message available in OCPP 2.0.1 have been modified in OCPP 2.1:

• Authorize response

• NotifyEVChargingNeeds request

• SetChargingProfile request

• TransactionEvent request

OCPP 1.6

Charger vendor Wallbox produced a paper explaining how to back port V2X to OCPP 1.6. The implementation is build upon OCPP 1.6’s DataTransfer message. The paper has been linked at the bottom of this page.

The V2X working group from the OCA is aware of this paper and discusses it in this thread. But the paper doesn’t have an official, public response from the OCA.