Inverter-Based Resource (IBR) Registration Initiative: What Category 2 Generator Owners and Operators Need to Know

Introduction

The rapid growth of inverter-based resources (IBRs) including solar PV, wind, battery energy storage systems (BESS), and hybrid facilities has fundamentally changed how the Bulk Power System (BPS) operates. While these resources bring flexibility and decarbonization benefits, they also introduce new reliability risks if not properly modeled, operated, and governed.

To address these challenges, the North American Electric Reliability Corporation (NERC) launched the IBR Registration Initiative, a multi-year effort to bring previously unregistered BPS-connected IBR owners and operators under the NERC compliance framework. As of May 2025, the initiative has entered its third and final phase: registration with a firm compliance effective date of May 15, 2026 for newly registered Category 2 entities 

This article explains:

• What Category 2 Generator Owner (GO) and Generator Operator (GOP) registration means
• Who must register and why
• Key timelines, documentation, and risks
• How Keentel Engineering supports IBR owners through registration and ongoing NERC compliance
  

Understanding Category 2 GO and GOP Registration

What Is Category 2?

NERC revised its Rules of Procedure (ROP) to formally define Category 1 and Category 2 Generator Owners and Operators. Category 2 primarily captures IBR facilities that were historically outside the NERC compliance registry but now meet revised Bulk Electric System (BES) and aggregation criteria 

In practical terms, Category 2 typically includes:

• Solar, wind, BESS, and hybrid facilities
• Aggregated resources ≥ 20 MVA
• Facilities interconnected at ≥ 60 kV
• Assets connected to the BPS, even if individually smaller
  
  

If a facility aggregates with others to exceed the threshold at a common point of connection, all participating facilities become Category 2 assets, triggering registration obligations 

Why This Registration Matters

Many IBR owners are encountering NERC registration for the first time. This is not a paperwork exercise it is a fundamental shift in regulatory exposure.

Once registered, Category 2 GO/GOPs become subject to:

• Mandatory NERC Reliability Standards
• Audit readiness expectations
• Model validation, protection, and performance requirements
• Event reporting, disturbance analysis, and coordination obligations

Failing to engage early increases the risk of:

• Incomplete or incorrect registration
• Delayed approvals
• Compliance gaps at the May 2026 enforceability date

NERC and the Regional Entities have been clear: timely cooperation is mandatory, not optional 

Registration Timeline and Key Milestones

According to NERC, Category 2 registrations are being processed in batches between August 2025 and April 2026, with a universal effective registration date of May 15, 2026 

Key takeaway:

Even though compliance enforcement begins in May 2026, registration activities are happening now, and Regional Entities are operating on different schedules.

Keentel strongly recommends initiating internal readiness at least 9–12 months before the effective date.

Required Documentation for Category 2 Registration

Entities must submit detailed technical and contractual information through CORES or a Regional Entity secure portal, including 

:

• Completed GO/GOP Asset Verification Form
• Interconnection Agreement (and amendments)
• Operating and third-party O&M agreements
• Electrical one-line diagrams (from resource to POI)
• Inverter or turbine nameplate data
  
  

This documentation is not just administrative—it becomes the foundation for:

• BES applicability determination
• Compliance scope
• Future audits and enforcement actions
  

Confidentiality and Data Protection

Some asset owners hesitate to share technical data without an NDA. NERC explicitly states that NDAs are not required. Instead, all submitted data is protected under ROP Section 1500 (Confidential Information), which legally binds Regional Entities to safeguard sensitive information 

Multi-Regional Entities and Phased Projects

Facilities in Multiple Regional Entities

If your organization owns or operates Category 2 facilities across multiple Regional Entity footprints:

• You must comply with each Regional Entity’s timeline
  
• Registrations may not be synchronized
• Separate approval letters may be issued
  

Phased Commercial Operation

Projects coming online in phases must register early, even if initial phases only meet Category 2 thresholds and later phases may elevate the facility to Category 1 status 

Life After Registration: What Changes?

Once registered, Category 2 entities must prepare for:

• Applicable NERC Reliability Standards (per the quarterly compliance dates matrix)
• Future transition to GADS reporting (effective May 15, 2026)
• CMEP oversight and possible inclusion in the Coordinated Oversight Program
• Cyber and physical security participation via E-ISAC membership (a free benefit of registration) 
  

How Keentel Engineering Supports Category 2 IBR Owners

Keentel Engineering specializes in bridging the gap between registration and real-world compliance. Our services include:

Registration & Applicability Support

• Category 2 GO/GOP determination
• BES and aggregation analysis
• Registration strategy across multiple Regional Entities
  

Technical Documentation & Engineering

• One-line diagram development and validation
• Inverter and BESS nameplate verification
• Interconnection and operating agreement reviews

NERC Compliance Readiness

• Reliability Standards applicability mapping
• PSSE / PSCAD / EMT model reviews
• Protection and control alignment
• Compliance program development and audit prep

Long-Term Compliance Support

• Ongoing advisory services
• Model validation updates
• Event response and disturbance analysis support
  

Expanded FAQ – Practical Answers for Asset Owners

Final Thoughts

The IBR Registration Initiative is not just a regulatory formality—it represents a structural shift in how inverter-based resources are governed within the North American grid. For Category 2 Generator Owners and Operators, early action, strong engineering support, and compliance-focused planning are essential.

Keentel Engineering stands ready to guide IBR owners through every phase—from registration to full NERC compliance—so there are no surprises when May 2026 arrives.