By Stefano Schnitger, NERC Reliability Specialist
Phase 2 of NERC’s inverter-based resource (IBR) registration initiative is in full swing. This phase will focus on the complete identification of Category 2 Generator Owner and Generator Operator candidates. The ERO Enterprise (NERC and the six Regional Entities) has already begun identifying potential registration candidates based on Energy Information Administration (EIA) 860 data, the NERC Compliance Registry (NCR), and information gathered from industry stakeholders. Phase 2 of NERC’s IBR registration initiative will last through May 2025. Once phase 2 is complete, phase 3 will commence. Phase 3 will culminate in the complete registration of Category 2 Generator Owner and Generator Operator candidates. This complete registration will finally bring these Generator Owner and Generator Operator candidates into the fold of applicability to the NERC Reliability Standards. The new Category 2 Generator Owner or Generator Operator registration criteria will apply to owners and/or operators of IBRs with an aggregate nameplate capacity equal to or greater than 20 megavolt-amperes (MVA) at an interconnection point of 60 kilovolts (kV) or greater, and that is material to the reliable operation of the interconnected bulk power system (BPS).
(source: IBR Registration Initiative Quick Reference Guide.pdf)
Inverter-based resources include modern wind turbines (type 3 and type 4 wind turbines), solar photovoltaics, battery energy storage resources, high voltage direct current circuits and flexible alternating current transmission system devices like static synchronous compensators and static volt-ampere reactive compensators. An inverter is a power electronic device that converts direct current (dc) electricity to alternating current (ac) electricity.
(source: 2023_NERC_Guide_Inverter-Based-Resources.pdf)
The power grid is experiencing a period of unprecedented transformation. Inverter based resources are being integrated into the bulk power system at an astonishing rate. IBRs are still a relatively new resource and if they are not integrated properly, they can have a detrimental effect on grid stability. Therefore, this rapid interconnection of BPS connected IBRs poses a high risk to grid reliability. This risk will continue to increase over the coming years because penetration levels of IBRs are growing rapidly. Most newly interconnected generation is inverter-based. This increased penetration is also coupled with significant levels of synchronous generation retirements. The speed of this change continues to challenge grid planners, operators, protection engineers, and many other facets of the electricity sector.
NERC is addressing the risk by requiring candidates who own and/or operate Category 2 inverter-based generating resources to register with NERC. Historically, Category 2 IBR owners and operators were not required to register with NERC or adhere to NERC’s Reliability Standards.
“System events over the past six years have shown that these resources are impacting the reliability of the bulk power system,” said Howard Gugel, vice president of Compliance Assurance and Registration at NERC. “It is imperative that we register these resources and modify applicable Reliability Standards to establish operating expectations.”
Inverter based resources present unique opportunities moving forward. They can contribute to a resilient and sustainable energy landscape of the future. If integrated correctly, inverter technology will provide significant benefits for the bulk power system. Maintaining grid reliability during this energy transformation is of paramount importance.