Introduction
The clock is ticking for inverter-based resource owners who haven't yet registered with NERC. May 15, 2026 marks a critical compliance deadline that many facility owners are only now becoming aware of—and the consequences of missing it could include significant penalties and operational restrictions.
NERC's IBR Registration Initiative represents one of the most significant expansions of reliability oversight in recent years. For the first time, non-BES (Bulk Electric System) inverter-based resources meeting specific thresholds will be subject to mandatory registration and compliance with NERC reliability standards. If your solar, wind, or battery storage facility connects to transmission at 60kV or above and has a capacity of 20 MVA or greater, this deadline applies to you.
This guide breaks down exactly what Category 2 IBR owners need to understand, the specific standards that will apply, and the steps required to achieve compliance before the May 2026 deadline.
Background: Why NERC Expanded IBR Registration
The Regulatory Foundation
NERC's IBR Registration Initiative emerged from growing concerns about grid reliability as inverter-based resources rapidly displaced conventional synchronous generation. Several high-profile disturbance events—including the 2016 Blue Cut Fire, 2017 Canyon 2 Fire, and multiple events in 2020 and 2021—demonstrated that IBRs could unexpectedly trip offline during grid disturbances, exacerbating reliability problems rather than supporting the grid.
FERC Order 901, issued in October 2023, directed NERC to develop registration criteria and applicable reliability standards for IBRs that were previously exempt from NERC oversight. The order specifically targeted facilities that, while individually below BES thresholds, collectively represent substantial generation capacity that affects bulk system reliability.
The result is a tiered registration system with three categories:
- Category 1: Existing BES-registered IBRs (already subject to NERC standards)
- Category 2: Non-BES IBRs ≥20 MVA connected at 60kV or above
- Category 3: Smaller IBRs that may be registered in the future based on reliability needs
Why This Matters Now
The May 15, 2026 deadline applies specifically to Category 2 facilities. These are resources that previously operated outside NERC's direct jurisdiction but now must:
- Complete formal registration with NERC
- Identify their Generator Owner (GO) and Generator Operator (GOP) functional entities
- Prepare for compliance with applicable reliability standards
- Establish data reporting and coordination with their Balancing Authority, Planning Coordinator, and Reliability Coordinator
The consequences of non-compliance are substantial. NERC can assess penalties of up to $1 million per day per violation for serious reliability standard violations. Even for less severe issues, enforcement actions can damage a facility owner's reputation and create financing complications for future projects.
Technical Requirements: Understanding Applicable Standards
Core Standards for Category 2 IBRs
Not all NERC reliability standards apply to Category 2 IBRs. NERC developed a tailored set of requirements focused on the specific reliability risks these resources present. The primary applicable standards include:
PRC-024-4 (Frequency and Voltage Protection Coordination): This standard requires IBRs to coordinate their protective relay settings to remain connected during frequency and voltage excursions within defined boundaries. The voltage and frequency ride-through curves specify exactly how long facilities must remain online during disturbances before tripping is permitted.
PRC-029-1 (Inverter-Based Resource Ride-Through): Working alongside PRC-024-4, this new standard establishes specific ride-through requirements for IBRs, addressing the momentary cessation issues that caused previous grid disturbances. Facilities must demonstrate they can continue operating—or quickly recover—during voltage and frequency deviations.
CIP-002 through CIP-014 (Critical Infrastructure Protection): Applicable CIP standards require Category 2 facilities to identify their BES Cyber Systems, implement security controls, and maintain cybersecurity programs. The specific requirements depend on facility classification as high, medium, or low impact.
MOD-026-2 and MOD-027-1 (Verification of Models): These standards require facility owners to provide accurate dynamic models to their Planning Coordinators and verify model performance against actual facility behavior. For IBRs, this increasingly means providing EMT (electromagnetic transient) models in addition to traditional positive-sequence models.
Regional Variations
Compliance requirements vary significantly across RTOs and ISOs:
ERCOT: As a non-NERC jurisdiction for registration purposes, ERCOT facilities follow Texas RE requirements but face similar technical standards. ERCOT's Operating Guides impose additional requirements for IBR performance during grid events.
PJM: PJM has been particularly proactive in requiring EMT models for IBR interconnection studies. Facilities in PJM should expect detailed model validation requirements and may face interconnection delays if models don't meet accuracy standards.
CAISO: California's high IBR penetration means CAISO has extensive experience with IBR integration challenges. CAISO's planning studies increasingly rely on facility-specific EMT models, and non-compliant facilities may face curtailment during reliability events.
MISO and SPP: Both RTOs are rapidly expanding their IBR modeling requirements as renewable penetration increases. MISO's MTEP process and SPP's ITP studies now incorporate IBR-specific reliability assessments.
Implementation Guidance: Steps to Compliance
Step 1: Determine Your Registration Category
Before May 15, 2026, facility owners must confirm whether their resources meet Category 2 criteria:
- Connected to transmission facilities at 60kV or above
- Aggregate nameplate capacity of 20 MVA or greater at a single point of interconnection
- Not currently registered as a BES facility
If you own multiple IBR facilities, each must be evaluated independently. A portfolio with ten 15 MW solar facilities may have some that qualify and others that don't, depending on their interconnection voltage and configuration.
Step 2: Identify Functional Entities
NERC registration requires identifying the responsible entities for Generator Owner (GO) and Generator Operator (GOP) functions. For many facilities, both roles are filled by the same organization, but this isn't always the case.
Consider:
- Who owns the physical generation assets? (GO responsibility)
- Who operates the facility and makes real-time decisions? (GOP responsibility)
- Are there third-party O&M agreements that affect functional responsibility?
The registration application must clearly identify these entities and their contact information.
Step 3: Conduct a Gap Assessment
Before registration, assess your current compliance posture against applicable standards:
For PRC-024-4 and PRC-029-1:
- Do your protective relay settings match required ride-through curves?
- Has your facility experienced any unexpected trips during grid events?
- Are your inverter firmware and control settings configured for grid support?
For CIP Standards:
- Have you identified BES Cyber Systems at your facility?
- Do you have documented cybersecurity policies and procedures?
- Are electronic access controls in place for critical systems?
For MOD Standards:
- Do you have current dynamic models for your facility?
- Have these models been validated against commissioning test data?
- Can you provide EMT models if requested by your Planning Coordinator?
Step 4: Develop Compliance Documentation
NERC compliance requires extensive documentation. Begin developing:
- Facility one-line diagrams with equipment ratings
- Protective relay settings and coordination studies
- Dynamic model files (PSS/E, PSCAD, or equivalent)
- Cybersecurity policies and evidence of implementation
- Training records for personnel with compliance responsibilities
Step 5: Submit Registration Application
Registration applications are submitted through the NERC Compliance Registry. The process involves:
- Creating an account in the NERC Compliance Monitoring and Enforcement Program (CMEP) portal
- Completing the registration application with facility details
- Identifying applicable reliability standards and requirements
- Designating compliance contacts and submitting for review
Allow at least 60-90 days for registration processing before the May 15 deadline.
Common Pitfalls to Avoid
Underestimating Timeline
Many facility owners assume registration is a simple administrative task. In reality, gathering required information, conducting gap assessments, and preparing documentation takes months—not weeks. Starting now is essential.
Ignoring Model Requirements
EMT modeling requirements catch many IBR owners off guard. Traditional positive-sequence models are insufficient for facilities in regions with high IBR penetration. Obtaining accurate EMT models from equipment manufacturers can take 6-12 months.
Assuming Previous Exemption Continues
Some facilities received informal guidance that they were "too small" for NERC oversight. The Category 2 threshold of 20 MVA at 60kV+ captures many facilities that previously operated without registration requirements.
Overlooking CIP Requirements
Cybersecurity compliance is often the most resource-intensive aspect of NERC registration. Facilities that have never implemented formal security programs face significant effort to achieve CIP compliance.
How GridStrong Helps
GridStrong specializes in helping IBR owners navigate NERC compliance requirements. Our team of power systems engineers and compliance specialists has guided dozens of solar, wind, and battery storage facilities through the registration process.
Registration Support: GridStrong can assess your facilities against Category 2 criteria, prepare registration applications, and coordinate with NERC and regional entities throughout the process.
Model Development and Validation: Our engineers develop and validate EMT models that meet RTO/ISO requirements. We work directly with inverter manufacturers to obtain accurate equipment models and tune them to match facility performance.
Gap Assessments: GridStrong conducts comprehensive gap assessments against applicable standards, identifying compliance deficiencies and developing remediation plans before registration.
Ongoing Compliance: Post-registration, GridStrong provides compliance monitoring, documentation management, and support during NERC audits and spot checks.
Conclusion
The May 15, 2026 NERC IBR registration deadline represents a fundamental shift in how inverter-based resources are regulated. Category 2 facility owners who haven't begun compliance preparations are running out of time.
The standards that apply—PRC-024-4, PRC-029-1, CIP-002 through CIP-014, and MOD-026/027—address real reliability risks that have caused grid disturbances across North America. Compliance isn't just a regulatory requirement; it's essential for maintaining the reliable operation of an increasingly renewable grid.
Don't wait until the deadline approaches. Talk to an Expert at GridStrong to assess your registration requirements and develop a compliance roadmap that ensures your facilities are ready before May 2026.
