New Standard Simplifies Certification Process, Overcoming V2G AC Technology Bottlenecks
UL Standards & Engagement officially released UL 1741 Supplement SC in May 2026, establishing certification specifications for vehicle-to-grid (V2G) AC charging systems for electric vehicles equipped with SAE J3072 bidirectional onboard inverters. The most significant breakthrough of this standard is the elimination of the requirement for certifying specific vehicle models and charging equipment as an integrated system. Instead, the charger serves as a "supervisory controller," working in conjunction with vehicles that meet the SAE J3072 standard, substantially simplifying the certification process.
Zach Woogen, Executive Director of the Vehicle Grid Integration Council (VGIC), stated that the new standard could catalyze a market for low-cost, scalable V2G AC systems while enhancing interoperability among charging equipment. He noted that the high certification barriers for V2G AC systems in the past were primarily due to the lack of unified standards, forcing automakers and charging equipment manufacturers to conduct individual certifications for each vehicle-charger combination, which was both time-consuming and costly.
Currently, only a few automakers, including GM, Ford, and Nissan, offer bidirectional charging capabilities, most of which are limited to vehicle-to-home (V2H) backup power applications and require proprietary charging hardware. True V2G functionality requires interconnection with utility systems, and the release of UL 1741 Supplement SC provides a clear certification pathway for V2G AC systems, facilitating broader commercial applications.
Multiple U.S. States Update Regulations to Accelerate V2G Technology Deployment
V2G systems are categorized into direct current (DC) and alternating current (AC) architectures. In DC systems, the inverter function is located in the external charging equipment, while in AC systems, it is built into the vehicle. As of the end of July 2026, regulators and utilities in California, Maryland, New York, Massachusetts, and Connecticut have clarified the treatment of V2G DC systems under existing or amended interconnection rules, removing regulatory barriers to their deployment.
For V2G AC systems, utilities in California and Maryland have established a certification pathway for multi-component distributed energy resource (DER) systems under the UL 1741 Certification Requirement Decision (CRD) in combination with UL 9741. This mechanism applies to matched vehicle-charger pairs, ensuring system operation in compliance with safety standards. Utilities in Nevada and Connecticut have proposed similar measures, which are currently under review and are expected to further expand the application of V2G AC technology.
Industry stakeholders widely believe that the release of UL 1741 Supplement SC will accelerate the commercialization of V2G AC technology. The new standard not only reduces system integration costs but also enhances compatibility among charging equipment, laying the foundation for the expansion of the V2G AC market. However, there has been no official response from automakers regarding the new standard, and the timeline for the approval of pending proposals in Nevada and Connecticut remains unclear. Nevertheless, as the regulatory environment continues to improve, the commercialization of V2G technology is expected to advance rapidly, bringing new opportunities for the integration of electric vehicles and the power grid.
