SunSpec and SAE Start a Critical Initiative to Enable Grid-EV Integration

Author: James Mater
Date: March 10, 2021

SunSpec and SAE kicked of a major initiative today (March 10, 2021) aimed at making IEEE 2030.5 a key communications protocol for management of EV charging and V2G (Vehicle to Grid) applications. Over 100 (at least 125 at the peak) people attended the kick-off chaired by Gordon Lum of Kitu and co-chaired by Rodney McGee of the University of Delaware (and an active participant in SAE activities).

The profile is focused on the SAE J3072 standard which defines communications between an EVSE and EV with an on-board inverter. The EVSE is what is called an AC power supply for the EV rather than a DC charger – i.e., the bi-directional inverter is on the vehicle rather than in the EVSE (Electric Vehicle Supply Equipment or charging station). J3072 generally applies to passenger vehicles but also any vehicle with AC Level 2 (SAE J1772) charging. In North America, all Level 2 AC charging for any size vehicle is based on J3072 and J1772. 

The protocol specified in J3072 and J1772 for communications between the EVSE and EV is IEEE 2030.5. This leads to the need for a Profile of IEEE 2030.5 for the J3072 EV communications so that the industry can standardize the communications and create a certification program for the on-board inverters and associated EVSEs. This profile will become to EV V2G applications what the CA Rule 21 CSIP (Common Smart Inverter Profile) is to rooftop solar integration into grid operations.

One other industry activity is of critical relevance to this effort. UL has started work on UL 1741 SC which is a certification specification for onboard PEV inverters conforming to IEEE 1547-2018 as applied to the unique aspects of PEV inverters. It will include standard IEEE 1547 functionality while accommodating the unique aspects of mobile storage systems and PEVs. That work is progressing in parallel to this IEEE 2030.5 profile work but both are critical to standardizing V2G applications. 

This is an interesting process since it is a joint activity between SunSpec and SAE but being managed by SunSpec. SunSpec will use its process to develop and approve a specification. Presumably, SAE will also use its normal approval process for adopting the resulting profile as an SAE standard. The artifacts will end up as a publicly available Profile from SunSpec. This is a major contribution by SunSpec to the potential for integrating EV managed charging and V2G applications into grid operations. 

The Work Group will be meeting frequently to develop the initial draft specification. For those that were on the kick-off call, the slides and details of future meetings will be forth coming. For further information, you could contact Tom Tansy at SunSpec, Gordon Lum at Kitu or Rodney McGee at University of Delaware. 

What is J3072?

SAE J3072 specifies the requirements for a grid support inverter system function which integrated into a plug-in electric vehicle (PEV). The onboard PEV inverter is bi-directional and connects in parallel to the electric power system (EPS) through the connected EVSE. 

From a protocol perspective, SAE J3072 defines the communications between PEV and the EVSE required for the PEV onboard inverter to be configured and authorized by the EVSE for discharging into the electrical grid through the EVSE interconnection. 

A short version of the communications interactions to be covered in the Profile is:

  • A PEV plugs into the EVSE and establishes communications through exchange of IEEE 2030.5 security certificates and other security protocols.
  • The PEV obtains from the EVSE the site-specific limits on charging and discharging, including specific controls and curve-based control settings.
  • Based on the site limits provided by the EVSE, the PEV adjusts its configuration settings and reports those back to the EVSE.
  • The EVSE provides Management information that is different than the IEEE 1547 defaults and verifies that the EV inverter system is properly configured for the site.
  • Ultimately, based on the interchanges and verification of EV inverter system configuration settings, the EVSE authorizes the EV to discharge (or may conclude that the specific EV system is not authorized to discharge). 
  • The EVSE and PEV continuously verify that the PEV is authorized to discharge.

Obviously, there is a lot more detail and many questions for the Profile group to answer. 

  • Will there be a conformance specification for both the EVSE and PEV 2030.5 interfaces? 
  • How does the Profile address or not address the processes for the EVSE to validate that a PEV inverter model is authorized for V2G applications in the specific jurisdiction? 
  • How does the EVSE obtain that site-specific settings for the EVSE? 
  • Do the battery storage functions in the IEEE 2030.5 standard adequately support the anticipated use cases for this profile? 
  • How far will the Profile go beyond establishing the authorization of a PEV to discharge into the grid? 

There are other questions that come up such as the relationship or competition with OCPP and ISO 15118 or OpenADR. Over time, GEI will try to shed light on these questions.

Bottom line, we think this effort will have a significant impact on the industry globally for V2G applications. Combined with UL 1741 SC, this EV Profile initiative will be a major step towards enabling integration of PEV onboard inverters into electric grid operations.