The North American bulk power system (BPS) continued to perform reliably in 2025 even as the grid experienced increasing operational complexity, the North American Electric Reliability Corporation said on June 24.
NERC’s 2026 State of Reliability (SOR) finds both measurable reliability improvements and emerging risks associated with the changing resource characteristics, growing demand, and more challenging operating conditions. New and emerging risks are evolving and reducing the margin for error, amplifying the potential for serious events on the bulk power system.
Ongoing grid reliability will depend not only on maintaining and expanding infrastructure and resource adequacy, but also on improving industry’s ability to anticipate, model, and mitigate these risks, NERC said.
“Both system operators and generators are being asked to do things today that they were never originally designed to do at this scale and pace,” said John Moura, director of Reliability Assessment and Performance Analysis. “What we found in this year’s assessment is evidence of both resilience and adaptation, but also a clear signal to stay ahead of the emerging risks before they become operational challenges.”
Attributed in part to industry’s weatherization efforts, the operational performance of conventional generation improved during the most challenging winter weather week of 2025. However, overall, a reduction in availability occurred throughout the year, largely driven by a decline in the performance of coal and combined-cycle generation.
The SOR identified a material increase to 9.2%, above historical norms of 7–8%, in conventional generator forced outage rates with coal and combined-cycle units experiencing a 39.8 TWh and 19.1 TWh increase in unavailable energy, respectively. This is driving a reduction in deployable reserves, which are shrinking as forced outage rates increase, creating potential for tight operating conditions that can lead to system events.
The surge in data center and computational loads remains a major reliability consideration owing to their scale, speed of development, and unique operational characteristics. During 2025, two instances of data center customer-initiated load reduction exceeded 1,000 MWs, with many more exceeding 100 MW.
“Events like this emphasize the growing need for accurate load modeling and operational coordination. We are continuing our efforts with both the electric and data center industries to issue new alerts, host technical conferences, perform standards work, and offer large load guidance activities,” said Jack Norris, manager of Performance Analysis.
In addition, NERC proposes to identify a new functional entity type, called “Computational Load Entity,” that will include certain large loads with a material impact on the BPS and develop mandatory Reliability Standards.
Rapid expansion in solar, wind, and battery energy storage systems (BESS), which are all inverter-based Resources (IBRs), continued in 2025. This continuing transformation of the resource mix is fundamentally changing system operations and reliability management. BESS, which grew at approximately the same rate as solar, continued to provide essential reliability services such as rapid frequency response, and offsetting wind and solar variability at this expanded scale.
The increase in IBRs creates more operational complexity, and, while the majority of NERC’s IBR mitigation plan is complete, NERC continues monitoring and efforts including new technical requirements related to IBR performance, ride-through capability, and model validation.
NERC’s recommendations, described fully in the SOR report, outline actions to help reduce reliability risks, including developing specific measurable reliability indicators for generation performance, continuing the publication of incident analysis and lessons learned and sharing findings with industry, and monitoring BESS performance and major events around the world to identify risks.
The recommendations also emphasize the need for continued coordination across industry, regulators, and policymakers.
The SOR reviews BPS performance in 2025, identifies trends and emerging reliability risks, reports on the relative health of the interconnected system, and measures the success of mitigation activities deployed.
The 2026 SOR Overview and the 2026 SOR Technical Assessment provide objective and concise information for policymakers and industry leaders on issues that affect the reliability and resilience of the North American BPS while providing strong technical support for those interested in the underlying data and detailed analytics.
