The North American Electric Reliability Corporation (NERC), the electricity reliability organisation (ERO) designated by the Federal Electricity Regulatory Commission (FERC), has released its 2025 State of Reliability (SOR) overview, providing a high-level summary of the performance of the bulk power system (BPS) during 2024. This annual assessment, supported by the more detailed SOR technical assessment, offers a data-driven evaluation of reliability, identifies emerging risks, and informs policymakers, regulators, and industry leaders on actions required to safeguard the resilience and security of the electricity grid.

Drawing on comprehensive performance data from 2020 to 2024, the report examines severe weather impacts, changes in resource mix, operational challenges from new demand sources, and advancements in frequency response technologies. The findings indicate:

  • Severe weather remained the leading cause of the most severe power system outages in 2024, including two major winter storms and five hurricanes. Despite their frequency and severity, improvements in generator performance and coordinated restoration efforts minimised major consequences, with no operator-initiated load shed attributed to these storms in 2024.
  • Data centers are identified as a major emerging reliability risk due to their large, rapidly growing, and volatile power demands, which outpace the ability to expand generation and transmission infrastructure. Sudden, simultaneous disconnections of such loads can cause major system imbalances, underscoring the need for better modeling and planning.
  • Battery energy storage systems (BESS) are increasingly supporting primary frequency response, especially in Texas, where BESS capacity grew rapidly and now provides fast, reliable frequency regulation. BESS have contributed to higher quality frequency response and have helped arrest system frequency declines more effectively than conventional resources.
  • Inverter-based resources (IBRs)—including wind, solar, and BESS—continue to pose specific reliability challenges. Unexpected IBR responses to grid disturbances (such as tripping offline in response to faults) have resulted in large drops in system output but are being addressed through new reliability guidelines, improved modelling, and regulatory requirements aimed at ensuring ride-through capability and more accurate event data reporting.

The 2025 SOR underscores that while the BPS remains robust, evolving threats require sustained vigilance and adaptation. NERC emphasises the need for continued investment in weather resilience, enhanced modelling of emerging large loads, integration of advanced storage technologies, and refinement of standards governing IBRs. By acting on the recommendations in the report, industry stakeholders can ensure that the North American grid remains secure, resilient, and capable of meeting the demands of a changing energy landscape.

The full report can be accessed here.