By Laura Christensen, Senior NERC Reliability Specialist
The North American Reliability Corporation (NERC) has introduced new terminology – Category 1 and Category 2 – to distinguish between different groups of inverter-based resources (IBRs) in its expanded Generator Owner (GO) and Generator Operator (GOP) registration regime. All currently registered NERC entities have been reclassified as Category 1 for GO and GOP registration. Now, let’s delve into what prompted this change, how it unfolded, and what it means for the electric industry.
Why the change? Historically, only larger generating resources – especially those directly connected to the bulk electric system (BES) – were required to register with NERC as a GO or GOP. Many inverter-based resources, particularly smaller ones like distributed solar, battery storage, or other DERs, escaped registration and oversight. As their deployment accelerated, grid planners grew concerned about the “reliability gap” introduced by these increasingly prevalent resources. NERC sought to close this gap by expanding registration requirements to cover more IBRs – prompting the need for clearer classification.1, 2, 3
Defining Category 1 vs Category 2
Category 1 IBRs:
- These are IBRs that are already registered under existing NERC thresholds
- Typically have a nameplate capacity ≥ 75 MVA, and are interconnected at voltage levels ≥ 100 kV.
- Resources include both individual generating facilities and aggregated “dispersed” resources meeting the same thresholds. 4, 5
Category 2 IBRs:
- A new category introduced for mid-sized IBRs not previously subject to NERC registration.
- Defined as inverter-based generating resources with aggregate nameplate capacity ≥ 20 MVA, interconnected at voltage ≥ 60 kV, and not part of the BES. 135
Implementation Timeline
- Proposal Phase
- NERC filed proposed revisions with FERC, renaming “GO-IBRs” as Category 2 GOs/GOPs after stakeholder feedback found the initial term confusing.
- FERC Approval
- FERC approved the new registration categories, formally recognizing Category 2 GO and GOP thresholds.
- Phase 2: Candidate Identification (May 2024 – May 2025)
- The ERO Enterprise (NERC + regional entities) identified potential Category 2 candidates using data sources like EIA-860, NERC’s registry, and stakeholder input.
- Phase 3: Registration and Outreach (May 2025 – May 2026)
- Completed registrations and candidate validations take place. Regional entities are actively collecting information and guiding GO/GOP applicants via the CORES system and outreach events.
- Targeted effective registration date: May 2026, although some tools (like CORES) are expected to be operational as early as August 2025. 1, 2, 3, 4, 5
These changes will bring a broader context and compliance impact to NERC registered facilities. The increased oversight will bring smaller IBRs under reliability standards to ensure performance expectations, modeling, and auditability. Rapid IBR growth, coupled with synchronous generation retirements, threatened grid stability – prompting NERC to act. Compliance planning, program development, and potential registration delays underscore early preparation’s importance.23
By introducing Category 1 and Category 2 IBR classifications, NERC has ensured its oversight model keeps pace with evolving grid dynamics. The approach is methodical – certain resources had always been under NERC’s purview; now the scope broadens to include mid-sized, inverter-based facilities. Operators and owners of these resources should act now, preparing for upcoming registration requirements and compliance obligations.
Sources:
- Climate Solutions Law, NERC Requests Approval To Expand Registration And Compliance Obligations To A New Category of Entities: Category 2 GOs/GOPs | Climate Solutions Legal Digest
- NAES Corporation, NERC Inverter Based Resource Registration Initiative Update – NAES
- JD Supra, NERC Requests Approval To Expand Registration And Compliance Obligations To A New Category of Entities: Category 2 GOs/GOPs | Husch Blackwell LLP – JDSupra
- Gridsme.com, Update Alert – NERC’s New Reliability Standards for Inverter-Based Resources
- MRO, Category 2 IBR Registration Initiative Update – Midwest Reliability Organization
