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Closing a 16 Percent Gap in Grid Oversight

Status of ERO Enterprise IBR Registration Initiative

By Bryan Clark, MRO Director of Reliability Analysis

Research by the ERO Enterprise (NERC + Regional Entities) identified a 16 percent gap in grid oversight, representing approximately 29 GW of inverter-based resources (IBRs) connected to the bulk power system that were not previously subject to NERC Reliability Standards. To address this gap, the Federal Energy Regulatory Commission (FERC) directed NERC in 2022 to develop a strategy for identifying and registering these resources. This led to the IBR Registration Initiative, which was officially launched in May 2023 after receiving FERC approval.

The initiative details how NERC will work with the six Regional Entities and industry stakeholders to revise NERC’s Rules of Procedure, establishing a new Category 2 for IBR Generator Owners (GOs) and/or Generator Operators (GOPs), and registering candidates for this function by May 15, 2026. This critical work enhances reliability of the bulk power system by creating visibility into IBR resources connected to the power grid, which are rapidly expanding, and bringing these impactful resources under federal oversight.

Defining Category 2 IBRs

A facility meets the new Category 2 GO/GOP threshold if it is an inverter-based generating resource that:

  • Contributes to an aggregate nameplate capacity of ≥20 MVA; and
  • Is connected at a voltage of ≥60 kV.

The number of identified Category 2 IBR facilities varies by region and continues to evolve as registration submissions are processed. While MRO initially identified 110 facilities, that figure was refined to 88 as of January 29, 2026. This decrease followed detailed analysis that determined certain resources did not meet the Category 2 registration criteria. Examples of why include the timing of commercial operations was past May 15 or the facilities were outside of MRO’s region. For more details on these figures, view the latest FERC filing.

Timeline and Progress

This initiative is currently in Phase 3, the final stage of the work plan. The primary goal is to ensure all identified candidates are registered as Category 2 GO or GOP by May 15, 2026.

  • August 2025: Regional Entities began issuing official NERC Registration Notification letters.
  • January 2026: MRO refined its list of candidates to 88 facilities (down from 110) following a detailed review of commercial operation dates and regional boundaries.
  • May 15, 2026: The official deadline for Phase 3, marking the effective registration date for all Category 2 entities.
Regional Support and Outreach

In addition to publishing several news articles on the topic, MRO has actively supported this transition through several key outreach efforts in 2025 to ensure affected entities are prepared for compliance:

DateActivity
May 20, 2025IBR Registration presentation at MRO’s Reliability, Security and CMEP Summit in Oklahoma City
May 31, 2025IBR resource page added to MRO website
August 13, 2025Dedicated IBR Registration Webinar
December 1, 2025MRO 101 curriculum posted for new registered entities
December 18, 2025Publication of new GO/GOP IBR Primer Document
Looking Ahead

As the May 15, 2026 deadline approaches, NERC and the Regional Entities will continue to provide quarterly progress reports to FERC. This initiative represents a critical step in evolving grid oversight to match the changing energy landscape, ensuring that the increasing integration of IBRs does not compromise the stability of the bulk power system.

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