by Troy Dahlgren, NERC Reliability Specialist
The winter storm of December 2022, known as Winter Storm Elliott, wreaked havoc on the United States’ power grid, resulting in unprecedented electric generation outages, natural gas production declines, and significant challenges for both electric and gas utilities. In a joint staff inquiry, the Federal Energy Regulatory Commission (FERC), the North American Electric Reliability Corporation (NERC), and various Regional Entities analyzed the event to understand its implications and provide recommendations for improving the resilience of the power system.
Winter Storm Elliott brought unique challenges to the energy grid. Substantial electric generation outages coincided with peak winter electricity demand, creating a critical situation. Several Balancing Authorities in the Eastern U.S. declared Energy Emergencies, necessitating firm load shedding measures to maintain grid reliability. The event marked the fifth time in 11 years that cold weather-related outages posed a significant threat to bulk-power system reliability.
Some of the key findings from the report include:
- Unprecedented Generating Unit Losses: During the storm, nearly 90,000 megawatts of generating capacity went offline simultaneously, placing enormous strain on the power grid.
- Generator Performance Issues: Approximately 80 percent of generating units failed to operate efficiently at temperatures above their documented minimum operating thresholds.
- Load Shedding: Several electric grid operators were forced to implement firm load shedding measures to maintain system reliability, further highlighting the severity of the situation.
- Natural Gas Infrastructure Challenges: Freeze-related production declines in the Marcellus (23 percent) and Utica (54 percent) shales, coupled with other gas infrastructure issues, led to a significant drop in natural gas pipeline pressures.
- Localized Emergencies: In some areas, such as the greater New York Metropolitan area, low natural gas pipeline pressures necessitated emergency measures, including the use of liquefied natural gas facilities to maintain service.
The joint inquiry’s key findings revealed that 55 percent of generating unit outages, derates, and failures to start were caused by freezing issues, while 24 percent were attributed to fuel issues. Natural gas fuel issues accounted for a substantial portion of these challenges. Additionally, 41 percent of outages were initially indicated by generator owners as mechanical/electrical issues, but they were found to be correlated with subfreezing temperatures.
To enhance grid resilience and better prepare for extreme weather events like Winter Storm Elliott, the joint inquiry provided the following recommendations:
- Enhanced Winterization: Utilities and power plants should invest in winterization measures to withstand extreme cold, including equipment insulation and fuel supply management.
- Diverse Fuel Sources: Encourage diversification of fuel sources to reduce reliance on natural gas during cold weather, ensuring a more resilient energy mix.
- Improved Communication: Foster better communication and coordination between electric grid operators, gas pipeline operators, and local distribution companies to respond more effectively to crises.
- Scenario Planning: Develop comprehensive scenario plans for extreme weather events, enabling utilities to anticipate challenges and take proactive measures.
- Infrastructure Investment: Invest in infrastructure upgrades to improve the reliability and flexibility of the power grid, especially in regions prone to severe weather.
The findings from the Winter Storm Elliott report emphasize the urgent need to address the vulnerabilities in the U.S. energy infrastructure, especially during extreme winter weather events. With millions of customers affected and unprecedented outages, the recommendations put forth by FERC and NERC underscore the critical importance of improving cold weather reliability for both the natural gas and electricity sectors.
As FERC Chairman Willie Phillips emphasized, it is essential to take action promptly to prevent future occurrences like Winter Storm Elliott. The interdependence between the electric and natural gas systems demands a collaborative effort to ensure energy reliability during extreme cold weather, and these recommendations serve as a blueprint for securing the nation’s energy grid against the challenges of winter.
The presentation to FERC can be found at https://www.ferc.gov/news-events/news/presentation-ferc-nerc-regional-entity-joint-inquiry-winter-storm-elliott. The final report is expected to be published soon.