How NERC’s IBR Program Targets Gaps in Renewable Integration

19 September 2025

The rapid expansion of renewable energy is changing how electricity grids operate. Traditional power plants, mainly coal, gas, and nuclear, provided stability through large spinning machines that naturally balanced frequency and voltage. In contrast, inverter-based resources (IBRs) like solar, wind, and battery storage behave differently because they connect to the grid through power electronics instead of mechanical rotation. This change has introduced new reliability concerns, including oscillations, frequency response challenges, and difficulties in system strength. To address these gaps, the North American Electric Reliability Corporation (NERC) introduced its IBR Registration Program. This program ensures that even smaller entities contributing to grid operations are properly registered, monitored, and required to follow reliability standards.

Why Reliability Gaps Exist with IBRs

IBRs have many advantages, such as clean energy production and flexible operation. However, their behavior under stress differs from conventional generators. Traditional plants provide inertia—an essential buffer against sudden frequency changes—while most IBRs do not. This means grid operators face faster changes and less time to react when problems occur. Another challenge is the tendency of IBRs to create forced oscillations, which can destabilize the grid if not carefully managed. These issues have been observed in regions with high renewable penetration, such as South Australia and parts of the U.S., where transmission strength and short-circuit ratios are declining. Without clear oversight, some IBR facilities remained outside NERC’s regulatory scope, creating blind spots in reliability management.

The Purpose of the NERC IBR Registration Program

NERC’s IBR Registration Program was launched to close these oversight gaps. The program identifies generating facilities that may have been overlooked under older registration criteria but still have a significant impact on grid reliability. For example, some solar or battery projects that individually seemed small might collectively form large clusters feeding into the transmission system. These clusters can influence voltage stability, short-circuit levels, and protection coordination. By bringing these resources under NERC’s registration framework, operators must comply with established reliability standards, participate in performance monitoring, and provide accurate modeling data. This shift ensures that no significant grid-impacting IBR operates without accountability.

How the Program Works

The IBR Registration Program sets thresholds and guidelines to determine which facilities must register. Instead of focusing only on large plants, it considers factors such as whether multiple IBRs are interconnected at a common point, their ability to impact transmission, and the potential consequences of tripping offline. Once registered, these facilities must follow reliability standards covering areas like voltage control, disturbance response, and cybersecurity. Importantly, they must also submit validated models of their inverters to system planners, ensuring accurate studies of grid performance. This is critical, as inaccurate models have been linked to past system events where inverters did not respond as expected.

Reliability Benefits of the Program

The program delivers several key benefits for grid stability. First, it increases visibility by ensuring all impactful IBRs are registered and tracked. Second, it improves coordination, since registered entities must follow established standards for communication and performance. Third, it strengthens system planning and operations, as validated inverter models help operators anticipate how resources will behave under stress. Perhaps most importantly, it reduces the risk of unexpected disconnections or oscillations, which have caused serious incidents in high-renewable regions worldwide. By addressing these reliability gaps proactively, NERC is positioning North America’s grid to handle a future with higher shares of inverter-based energy.

Challenges Faced by the Industry

While the IBR Registration Program offers clear benefits, it also presents challenges for developers, operators, and regulators. Many inverter-based facilities were initially designed with minimal requirements for data reporting or disturbance response. Updating these facilities to meet NERC standards may require technical upgrades, such as improved control systems or better communication links with grid operators. For developers, this means higher costs and longer project timelines, especially for sites that were planned before the program came into effect. There is also the issue of model validation. Some inverter manufacturers are reluctant to share detailed information, citing intellectual property concerns. Without accurate models, however, planners cannot fully understand how the grid will behave under stress. Striking a balance between transparency and proprietary protection remains an ongoing debate.

Another challenge lies in workforce training. Grid operators and planners must adapt to a new era where system stability no longer relies solely on inertia but on advanced control strategies. This shift demands updated education, simulation tools, and operational procedures. Ultimately, while the transition is demanding, it is a necessary step to avoid widespread reliability risks as renewables become the backbone of electricity supply.

Lessons from International Grids

The issues NERC is addressing are not unique to North America. Other regions with high renewable penetration have already faced reliability crises linked to IBRs. In South Australia, for example, a system blackout in 2016 highlighted the risk of large-scale inverter disconnections during disturbances. Subsequent reforms introduced stricter performance requirements for solar and wind farms, as well as advanced inverter standards that allow resources to ride through disturbances instead of shutting down. Similarly, in Europe, grid operators have had to develop new rules to manage system oscillations and frequency stability in areas with dense wind generation.

These international experiences provide valuable lessons for NERC’s approach. They show the importance of proactive registration, standardized performance criteria, and collaboration between regulators, manufacturers, and operators. By learning from these examples, NERC can avoid repeating mistakes and instead create a forward-looking framework that ensures resilience as renewable penetration increases.

Compliance Implications for Operators

For operators of inverter-based facilities, registration is more than just a formality—it carries significant obligations. Once an IBR facility is registered under NERC’s rules, it must comply with standards covering reliability coordination, disturbance reporting, and event response. This includes providing accurate telemetry, ensuring voltage and frequency support, and maintaining cybersecurity protections. Facilities may also face audits to confirm compliance, with penalties possible for violations.

Some operators may see this as a burden, but in reality, compliance helps protect their own investments. By aligning with NERC’s reliability framework, operators reduce the risk of forced disconnections, equipment damage, or reputational harm. Furthermore, participation in the program creates a clearer relationship with transmission operators, allowing smoother integration of resources into long-term system planning. In the long run, compliance ensures that IBR facilities are seen not as risks but as essential contributors to grid stability.

Future Outlook of the IBR Registration Program

Looking ahead, the IBR Registration Program is likely to expand and evolve as grid conditions change. Current thresholds may be revised as renewable penetration increases and as clustering of smaller resources becomes more common. There is also potential for tighter coordination with distribution-level regulators, since many IBRs connect at the distribution grid but still affect transmission reliability. Another area of development will be advanced inverter functionality. Modern inverters are increasingly capable of providing “grid-forming” support, meaning they can help establish voltage and frequency rather than simply following existing signals. As these technologies mature, NERC may update its standards to ensure these capabilities are fully utilized.

The broader trend is clear: the future grid will rely heavily on IBRs, and programs like this one are essential to ensure stability. While the transition is not without challenges, it also presents opportunities to build a cleaner, more flexible, and more resilient power system. By acting early, NERC is helping to create a pathway where renewable growth does not come at the expense of reliability.

Key NERC Standards for IBR Registration Compliance

Standard	Focus Area	Purpose	What IBR Owners Must Do
PRC-024-4	Frequency and Voltage Protection	Prevents protective settings from causing unnecessary trips during system events.	Review and coordinate frequency/voltage trip settings so resources stay online during normal disturbances.
PRC-029-1	Ride-Through Capability	Requires IBRs to remain connected during temporary frequency and voltage swings.	Ensure equipment can “ride through” short disturbances without tripping, avoiding cascading outages.
MOD-032 / MOD-033	Modeling and Data Submission	Provides planners with accurate system models to study reliability impacts.	Submit validated dynamic models and operating data that reflect actual performance.
FAC-001 / FAC-002	Facility Interconnection	Governs how IBRs connect and interact with transmission systems.	Document interconnection agreements, coordinate with transmission planners, and verify impacts on the bulk power system.
CIP Standards (CIP-002 through CIP-014)	Cybersecurity	Protects grid assets from cyber risks.	Identify critical assets, apply access controls, implement incident response, and manage supply chain risks if classified as subject to CIP.