Five Essential Screening Questions for V1G and V2G Projects – A Practical Checklist for EVSE Engineers
The electric vehicle revolution is no longer just about getting from point A to point B. Today, EVs are becoming active participants in the power grid, capable of not only consuming electricity but also storing it and sending it back when needed. This concept, known as Vehicle-Grid Integration, encompasses two key approaches. V1G, or unidirectional smart charging, allows the grid to communicate with the EV to intelligently schedule charging, typically shifting it to off-peak hours when electricity is cheaper and grid stress is lower, but the EV never sends power back. V2G, or bidirectional vehicle-to-grid, transforms the EV into a mobile battery that can both charge from and discharge energy back to the grid, providing valuable services like frequency regulation and peak load reduction. The benefits are substantial, as smart charging with V1G can increase grid hosting capacity by forty to fifty percent, while V2G has the potential to reduce investments in grid infrastructure by approximately fifty percent. But with great potential comes great complexity, especially when it comes to interconnection requirements. The challenge is that many engineers and project developers enter this space without a clear framework for evaluating whether their EV charging project is technically and regulatory compliant. The industry is filled with acronyms like UL 1741 SA, SB, CRD, IEEE 1547, and ISO 15118 that aren't taught in university courses, and the specific requirements vary by jurisdiction. That is why I have developed this practical five-question checklist to help you navigate the technical due diligence process for V1G and V2G projects, whether you are an engineer, a project developer, or someone looking to break into the EV infrastructure space.
The very first and most fundamental question to ask is whether the equipment supports bidirectional power flow. Not all EV chargers are created equal, and this distinction determines the entire scope of your project. V1G systems are unidirectional, only drawing power from the grid to charge the vehicle, using communication protocols like ISO 15118-2 that handle smart scheduling but do not support energy export. V2G systems, on the other hand, require bidirectional capability, meaning the EV must be able to both charge and discharge, which is enabled by protocols like ISO 15118-20 that natively support bidirectional power transfer. This matters enormously because if your project involves V2G, you need hardware on both the vehicle and the EVSE side that supports bidirectional power flow; you simply cannot retrofit a unidirectional charger to do bidirectional as it is a fundamental design difference. When evaluating equipment, you should always check the manufacturer specifications for terms like bidirectional, V2G-capable, or ISO 15118-20 compliant, and also verify that the specific vehicle model supports bidirectional discharge, since not all EVs do.
The second critical question is whether the system is intended to export power to the grid, as this determines the entire regulatory pathway for your project. Non-exporting systems, which may still be bidirectional for vehicle-to-home or vehicle-to-building applications, operate in parallel with the grid but never send power back to the utility, often using software locks or power control systems to prevent export. Exporting V2G systems, however, actively send power from the vehicle battery back to the grid and require a formal interconnection agreement with the local utility. This distinction is crucial because exporting systems are treated more like generators than loads, and in many jurisdictions, V1G connections fall under demand connection codes while V2G falls under requirements for generators, which means different technical requirements, different application processes, and potentially different fees. To navigate this, you need to be crystal clear about your use case. If you are only providing backup power to a building without exporting, you may have a simpler path than full V2G, but even non-exporting bidirectional systems may require specific certifications like UL 1741 CRD for Multimode.
The third question, and one where many projects get tripped up, concerns the equipment's certification status, specifically UL 1741 SA, SB, or CRD. The UL 1741 standard family is the cornerstone of inverter certification in North America, but the specific version matters enormously. UL 1741 SA validates smart inverter grid-support functions like anti-islanding protection, voltage ride-through, and volt-var or watt control, developed in conjunction with California Rule 21 Phase 1 requirements. UL 1741 SB aligns advanced-function testing more directly with IEEE 1547-2018 requirements using the test methods in IEEE 1547.1 and represents the newer, more rigorous standard. UL 1741 CRD for Multimode specifically addresses systems that can operate in both grid-interactive and islanded modes, including tests to ensure that distributed energy resources do not export to the grid when operating in an islanded state. This is not just academic; New York State, for example, required all new inverters to be UL 1741 SB certified as of January 1, 2023, but recognizing the industry's transition challenges, they granted waivers for bidirectional EV chargers, first until July 1, 2024, and then extended to July 1, 2025. So you must check the certification label on your equipment, and if you are working with UL 1741 SA equipment, verify whether it is grandfathered under any applicable waivers, while for multimode systems, UL 1741 CRD for Multimode is increasingly becoming a requirement.
The fourth essential question addresses whether the project involves islanding or whole-home backup, which refers to the ability of a system to continue operating and powering local loads when the main grid goes down, a key feature of many vehicle-to-home applications. This capability fundamentally changes the certification requirements because systems that can intentionally island must be certified to UL 1741 CRD for Multimode to ensure they will not back-feed into a de-energized grid, a serious safety risk for utility workers. If your project involves whole-home backup or any form of intentional islanding, you will need UL 1741 CRD for Multimode certification, and this applies whether you are exporting to the grid or not. The Joint Utilities of New York have explicitly stated that all interconnection applications proposing V2G and V2H functionality must be certified to UL 1741 CRD for Multimode, so this is a requirement you cannot overlook.
The fifth and final question asks which applicable standards apply, as this is where it all comes together because several standards intersect in the V1G and V2G space. IEEE 1547-2018 governs the interconnection and interoperability of distributed energy resources, with Category III specifying the most stringent ride-through requirements, while IEEE 1547.1 provides the test procedures for IEEE 1547 compliance. IEEE 1547.9 Annex B specifically addresses EV and EVSE interconnection, and IEEE Std 2030.1.1-2021 provides technical specifications for EV charging infrastructure. SAE J3072 covers interconnection requirements for EVSE, ISO 15118 governs communication between the EV and charging station including Plug and Charge and bidirectional energy transfer, and UL 1741 in its various supplements covers safety and performance for grid-tied power electronics. These standards are not optional; they are the technical foundation that utilities and regulators use to evaluate interconnection applications, and understanding which ones apply to your project is essential for a smooth approval process. You should start with IEEE 1547-2018 as your baseline, then determine which specific standards apply based on your use case regarding V1G versus V2G, exporting versus non-exporting, and islanding versus non-islanding, while also working with your equipment manufacturer to confirm which standards their products have been tested against.
To put this all together in a practical decision framework, consider how the five questions interact. For a simple V1G smart charging project, the equipment is not bidirectional, it does not export, it typically only requires UL 1741 SA certification, and it does not involve islanding. For a vehicle-to-home project, the equipment is bidirectional, it does not export to the grid, it requires UL 1741 CRD for Multimode, and it does involve islanding. For a full V2G exporting project, the equipment is bidirectional, it does export, it requires UL 1741 SB along with a formal interconnection agreement, and islanding may or may not be involved. For a V2G project with islanding, the equipment is bidirectional, it does export, and it requires both UL 1741 SB and UL 1741 CRD for Multimode, with islanding present. The bottom line is that the EV infrastructure space is evolving rapidly, and New York State has already approved standardized interconnection processes for EV chargers to keep pace with aggressive zero-emission vehicle targets, with similar developments happening across North America and globally. But standards alone are not enough; the real challenge is having the foundational knowledge to understand what these requirements mean for your specific project, and that is exactly the kind of practical, industry-ready knowledge that university courses do not teach. If you are looking to build a career in this space or simply want to navigate your next EV infrastructure project with confidence, understanding these five screening questions is a great place to start, as the power utility industry is growing rapidly and needs professionals who can bridge the gap between theoretical knowledge and real-world application.
Mike has spent years working in the power utility industry across various roles, teaching engineering concepts to the public, fellow engineers, and power line professionals. He understands firsthand how university courses often fail to prepare graduates for the practical realities of the industry, from industry-specific lingo to the nuanced technical requirements that are not found in textbooks. His courses are designed to teach real-life skills that are directly applicable to the industry, helping students land their dream jobs without wasting valuable time. If you are ready to take your knowledge to the next level, explore Mike's comprehensive courses on power utility industry fundamentals and EV infrastructure through the link below.
