Navigating NERC PRC-029-1: A Field Guide for Inverter-Based Resource Owners

Ryan D. Quint, PhD, PE

President and CEO, Elevate Energy Consulting

President and Chief Engineer, GridStrong

On July 24, 2025, the Federal Energy Regulatory Commission (FERC) issued Order 909 approving NERC PRC-029-1, introducing new frequency and voltage ride-through performance requirements for inverter-based resources (IBRs). This standard, alongside the newly adopted PRC-024-4 for synchronous generators, signals a shift in expected performance of IBRs to support the bulk power system (BPS) during grid disturbances

At Elevate Energy Consulting, we’re actively guiding asset owners and developers through the regulatory, technical, and operational implications of this change. The Elevate team has devised a comprehensive PRC-029 IBR plant design evaluation approach to support improved ride-through performance of IBRs and to support compliance with PRC-029.

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Understanding PRC-029-1: Ride-Through Redefined

PRC-029-1 establishes minimum ride-through criteria for frequency and voltage excursions, mandating that IBRs remain connected and operational through defined disturbance profiles. This closes a longstanding reliability gap that has been reported in numerous NERC disturbance reports. Resources that trip offline prematurely or abnormally for normal grid events such as faults can exacerbate instability, particularly as IBR penetration levels continue to rise.

Scope of Applicability

PRC-029-1 applies to both BES (Bulk Electric System) IBRs and registered Category 2 IBRs:

• BES IBRs: Gross nameplate capacity >75 MVA, connected at ≥100 kV

• Non-BES IBRs: Gross nameplate capacity ≥20 MVA, connected at ≥60 kV

Both categories are subject to to the same technical requirements; however, implementation timelines differ slightly.

Requirements Overview

The standard includes four main requirements:

• R1–R3 (Design and Operation): These provide the technical specifications for how the IBR must be designed and operated to reliably ride through events defined by the PRC-029 performance curves.

  • Design compliance includes designing, configuring, and parameterizing the IBR plant protection settings, controls, and operating modes of the inverters, relays, balance of plant protections, etc., to meet the ride-through performance obligations. This involves conducting a thorough plant protection and control assessment, verifying that the dynamic model(s) are reflective of the latest configurations, and conducting ride-through simulations to prove that the IBR plant can effectively withstand the required frequency and voltage conditions.

  • Operational compliance requires IBR plants to ride through actual grid events, leveraging the disturbance monitoring equipment and measurements from NERC PRC-028-1.

• R4 (Legacy Exemption Requests): This allows Generator Owners (GOs) to request exemptions to specific requirements for existing resources that cannot meet the requirements. Software-based updates are required; however, exemptions may be sought for hardware-based limitations.

  
  

Implementation Timeline

For BES IBRs:

• Design Requirements (R1–R3): Must be met by October 1, 2026

• Operation Requirements (R1–R3): Must be met after compliant disturbance monitoring equipment is in place per PRC-028-1

• R4 Exemption Documentation: Due by October 1, 2026

For Non-BES IBRs:

• Design Requirements (R1–R3): Must be met by January 1, 2027 or the standard’s effective date, whichever is later

• Operation Requirements: Triggered after PRC-028-1-compliant monitoring is operational

• R4 Exemption Documentation: Due by January 1, 2027, or the standard’s effective date

  
  

Note: The effective date of PRC-029-1 is expected to be October 1, 2026, defined as the first day of the first calendar quarter 12 months after FERC’s approval. This should be verified with NERC documentation once released.

Legacy Equipment and Exemption Requests

A 12-month exemption request window begins on the effective date. During this period, GOs of existing IBRs—those placed in service before October 1, 2026—may seek limited exemptions for technical hardware-based limitations per Requirement R4. However, exemptions must be supported by thorough documentation justifying the need for the exemption.

FERC Directives to NERC for Potential Revisions

FERC directed NERC to broaden the acceptable forms of evidence beyond OEM-provided damage curves. This may include inverter manufacturer certification, commissioning test data, or engineering analyses that demonstrate non-compliance cannot be corrected through reasonable means.

FERC also directed NERC to consider exemptions for the following:

• HVDC-connected IBRs with thermal or design-based ride-through limitations (e.g., offshore wind with chopper circuits)

• Long-lead time projects already in development prior to the effective date

If any hardware modifications are made after an exemption is granted, GOs are required to notify their Planning Coordinator, Transmission Planner, Reliability Coordinator, and Transmission Operator within 90 days and must then comply with all applicable portions of R1–R3.

Compliance Planning: Key Considerations

With the clock ticking toward implementation, asset owners and developers should start the IBR plant ride-through design evaluations now. This includes:

• Review project designs and as-left settings including the inverter, relays, power plant controller(s), etc., against PRC-029-1 performance specifications

• Gather any additional documentation from OEMs regarding maximum equipment capabilities and any possible need for exemptions; ensure future resources are fully compliant “out of the box," particularly for newly connecting resources

• Conduct PRC-029 design evaluations including protection and control verification and simulation-based assessments to justify compliance with PRC-029 ride-through obligations

• Begin implementing PRC-028-1 disturbance monitoring equipment to ensure operational compliance can be verified post-deployment

• Evaluate legacy assets for potential upgrade any necessary exemptions and prepare documentation accordingly

  
  

Looking Ahead

FERC has also required NERC to submit a report 18 months after the close of the exemption window, detailing the volume, nature, and system-wide impacts of granted exemptions. This signals growing regulatory scrutiny around IBR performance and reinforces the long-term expectation that all grid-connected resources provide essential reliability services—including fault ride-through capability.

How Elevate Can Help

Elevate supports clients across all stages of the PRC-029-1 implementation lifecycle, including:

• Developing compliance procedures

• Strategizing on compliance roll-out plans

• Reviewing as-left protection and control settings

• Coordinating with with OEMs

• Simulation-based design evaluations in PSCAD, PSS/E, PSLF, etc.,

• Compiling documentation for any technical limitations for exemptions, as needed

• Supporting PRC-028 disturbance monitoring gap analyses

• Preparations for PRC-030 event analyses for any ride-through failures

For more information on how your fleet or project may be impacted, or to request support navigating these requirements, reach out to us at info@elevate.energy or visit us at www.elevate.energy.

Reference Materials

• FERC PRC-029-1 Final Order (Docket RM25-3-000)

• NERC PRC-029-1 Implementation Plan

• NERC Statement on PRC-029-1