Vehicle-to-Home (V2H), Vehicle-to-Grid (V2G), at Scale, Today

The EVs that people own today are capable of Vehicle to Home (V2H) and Vehicle to Grid (V2G) with a software change allowing for negative current.

The question of whether V2H/V2G can be provided at scale has been something that many have pondered. Sunil Chhaya, Ph.D. Chhaya from Electric Power Research Institutes (EPRI)has been passionate about this subject for years. Flex Power Control (FPC) has developed the Smart Power Integrated Node (SPIN), which has been designed from the ground up to address a variety of issues driven by the introduction of large energy sources/loads at home. V2H/V2G are issues that SPIN addresses, along with when and how to deliver it, while providing consumers unprecedented value.

There are several factors that need to occur for V2H/V2G to be at scale. V2H/V2G needs to be done with open standards, systems need to have interoperability, CCS and or NACS connection, and finally, the protocols DIN70121 and/or ISO 15118-20 need to be in place. And of course, the vehicle OEMs must allow discharge of the vehicle.

Proprietary V2H systems have been popping up, but these limit consumers to a certain vehicle or vehicle manufacturer. In contrast, open systems such as SPIN, can charge/discharge any vehicle. The vehicle only needs to give permission to charge/discharge, with certain constraints. Interoperability will allow the consumer to lease or purchase the vehicle of their choice. CCS and NACS is a numbers game, essentially providing the entire Plug-in Electric Vehicle (PEV) as a potential usable asset for V2H/V2G. Standards are still needed that will permit the discharge of the vehicle.

The charge or discharge of a vehicle is determined by permissions. Permissions are set by the vehicle, and in the case of discharge for V2H/V2G, it is an allowance of negative current. V2H/V2G is essentially that simple, but it can be much more complex than just an allowance of negative current. These complexities are driven by the number of Use Cases that a vehicle could find itself in, such as a variety of utility territories that each define what will be received in return, when a discharge can take place, etc. With SPIN, though, the market factors of that particular utility territory are already known, and any constraints (placed by the OEM, the utility, or the vehicle owner), will be adhered to by SPIN. Also, SPIN doesn’t look at just the vehicle, it is looking at all the DERs it has at its disposal. SPIN lives within the constraints of the resources it has and executes the objectives that a consumer and or the utility has set. The reality is that just allowing the provision for current to be negative will open up the door today for V2H/V2G. This discharge can be limited by the OEM by placing constraints on the system with which they feel comfortable, but V2H/V2G can happen today.

We can make the statement that V2H/V2G can be realized today, because Flex Power Control has demonstrated V2H/V2G with SPIN using two production vehicles and one prototype vehicle. The production vehicles were calibrated to allow discharge. The vehicles used were from three different vehicle manufacturers. This provides evidence that V2H/V2G can happen with the existing PEV in the field. SPIN is capable of charging/discharging PEV’s today. As far as the standards both CCS and NACS use DIN and ISO 15118 protocol. The essential difference between CCS and NACS is the connector itself. EPRI’s Sunil Chhaya provided the following at the Infrastructure Working Council meeting April 19, 2023:

  • We are in the CCS Type1/Type2 DC charging domain today, driven by DIN70121 [Subtext – 15118-20 won’t be available at scale for another 4 years. Some OEMs may do it, but the industry must move – I don’t see how that happens in the next 2-3 years].
  • Logical next step is to evolve IEC/ISO15118-02 to be bidirectional – converting all EVs with a software change into bidirectional DC Charging capable EVs [EPRI demonstrated with Flex Power in August 2021] – Rich Scholar plan with SAE/ISO – we endorse it.
  • 15118-20 is probably the long-term solution, but the route to V2G at Scale runs through the next revision of 15118-2, which is available today.

This is a realistic and pragmatic view of where we stand on V2H/V2G. I wish to thank EPRI and especially Sunil Chhaya and his team for the work they do. I want to stress, though, that this is about a path to reach scale, helping the grid and value proposition of EVs today.

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