State of the Interconnection 2026
Reportable Events
The number of reportable events on the system decreased slightly in 2025, although one event, on November 13, 2025, had a significant impact — loss of load for roughly 250,000 customers in Wyoming, South Dakota, Montana, and Nebraska. The outage was the first Category 3 event in the Western Interconnection in more than a decade.
Protection System Misoperations
The correct operation of protection systems is a key measure of system performance. The misoperations rate has steadily decreased over the last five years, continuing a decade-long decline in misoperations resulting from a concerted effort between WECC and industry.
Energy Emergency Alerts
The interconnection saw a significant decrease in energy emergency alerts (EEA) in 2025, due at least in part to more moderate weather throughout the year. Most of the EEAs in 2025 occurred during the shoulder season, when planned maintenance tends to occur, tightening reserve margins.
System Events
Reportable Events
There were 32 reportable events on the bulk power system in the Western Interconnection in 2025, down from 35 events in 2024. This includes the first Category 3 event or higher in at least a decade.
While the decrease in the number of events is a positive indicator, the severity of the Category 3 event reflects challenges to the system. Approximately 250,000 customers lost power in the Category 3 event, which occurred on November 13, 2025, and quickly cascaded into a regional concern after several high-voltage transmission lines tripped offline along with almost 5 GW of generation.
Protection System Misoperations
Misoperations involve the unexpected performance of protection systems, which are critical components of the electric system that remove faults and protect sensitive equipment. Misoperations occur when the protection equipment does not perform as designed and can contribute to outages of generation and transmission.
The misoperations rate has declined each year since 2021. The 2025 rate (4.5%) was the lowest since 2020 (also 4.5%) and is down from 5.85% in 2017.
Unplanned Transmission Outages of Three or More Elements
Although most unplanned transmission outages involve only a single element, outages involving three or more elements are more likely to lead to loss of load. The number of outages involving three or more elements increased in 2025 to 34 events, from 29 in 2024.
Four of the incidents were tied to the November 13, 2025, outage that affected 250,000 customers in the northeast of the interconnection.
Energy Emergency Alerts
There were eight EEAs in 2025, a significant decrease over previous years. Seven of the alerts were EEA-3s, defined as a situation in which firm load interruption is imminent or in progress. There were 30 EEAs in 2024.
An EEA is an emergency procedure in which a Balancing Authority has an energy emergency and may need help from others to maintain resource adequacy. There are three levels of EEAs, with Level 1 being the least severe and Level 3 the most severe.
In the past, extreme weather events have been responsible for most of the EEAs in the Western Interconnection, both hot and cold weather, as they lead to increased demand and can affect generation. There were fewer such events in 2025. Instead, in 2025 (and into 2026), resource adequacy issues have arisen more often in the shoulder months when generation resources are offline for scheduled maintenance.
In 2025, three EEA-3s were reported in the first quarter, all the result of one Balancing Authority experiencing forced generator outages that made the entity reserve deficient. There were four EEA-3s in the third quarter of 2025, with three events linked to unplanned generation outages in one Balancing Authority, leaving them deficient in contingency reserves. Loss of load did not occur in any of these events.
Power Outage Affected 250K
Approximately 250,000 customers lost power on November 13, 2025 after a system disturbance led to cascading outages that impacted parts of Montana, South Dakota, Wyoming, and Nebraska.
WECC is working with NERC and the appropriate entities to review the event, during which roughly 4.8 GW of generation and dozens of transmission facilities were affected.
WECC Issues Report on Moss Landing Battery Storage Fire
A fire at the Moss Landing battery energy storage facility in California in January 2025 destroyed a building that housed 300 MW of storage capacity and raised concerns about the safety of battery energy storage systems. WECC collaborated on a report about the incident with FERC, NERC, and CAISO. While the report did not constitute a root-cause analysis of the incident, it provided recommended actions for mitigating the fire risk associated with battery energy storage systems.
Risk Management Program
WECC’s Risk Management Program is designed to collaboratively address both established and emerging risks to the reliability and security of the Bulk Power System in the West. The program was updated in late 2025 to provide continuous assessment of the most significant risks, with an update on the identification, ranking, and treatment of risks reported at each quarterly WECC Board of Directors meeting.
To ensure the active engagement of stakeholders across the industry, the program calls for WECC staff to host a workshop twice annually to discuss prioritization and treatment, as well as any new or emerging risks. The first meeting is scheduled for July 8, 2026.
WECC Launches Assurance Program to Mitigate Risk
WECC launched the Extreme Weather Preparedness Assurance Program in 2025 to help entities mitigate the reliability risks associated with extreme weather.
Extreme weather can wreak havoc on the Bulk Power System, stressing equipment due to increased demand for heating or cooling. There have been several such incidents across the continent in recent years. WECC’s assurance initiative is designed to mitigate that risk. WECC staff works with participants in the voluntary program to improve policies, processes, and procedures related to extreme weather.
Resources available include access to small group advisory sessions, best practices, and lessons learned from past events. In the initiative’s first year, WECC has worked with nearly three dozen entities and conducted six site visits, providing each entity visited with a report on the status of its extreme weather preparation efforts. Among the best practices:
- Efforts to continuously improve
- Incorporating insights from industry disturbance reports
- Engagement in industry forums and groups
- Enhanced communication efforts before, during, and after an extreme weather event
- Drills for extreme-weather operations
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