The PJM Interconnection was able to maintain system reliability and serve customers throughout the extreme weather that affected the regional transmission organization from Dec. 23 through Dec. 25, 2022, according to a PJM report.
The Winter Storm Elliott Event Analysis and Recommendation Report noted that PJM operators were able to avoid electricity interruptions and even support its neighbors during certain periods, although the operators had to implement multiple emergency procedures and issue a public appeal to reduce energy use.
Winter Storm Elliott’s rapidly falling temperatures coincided with a holiday weekend that combined to produce unprecedented demand for December, which was further complicated by unexpectedly high resource unavailability and/or failures to perform, the report said.
On Dec. 23, the first day of the storm, the stress on PJM’s neighbors began to signal extreme conditions headed for the PJM region. The Southwest Power Pool set a new winter peak on that day. The Tennessee Valley Authority experienced the highest 24-hour electricity demand supplied in its history. PJM was able to export energy to TVA, Duke Carolinas and Duke Energy Progress before having to curtail most exports during peak conditions in the face of emergency conditions.
PJM’s forecast for Dec. 23 was about 127,000 megawatts, and load came in at about 136,000 MW, about 25,000 MW above a typical winter peak day. In preparation, PJM had approximately 158,000 MW of operating capacity plus available generation able to be called upon in real time and was able to meet load with the help of a Maximum Generation Action and Demand Response.
The next day, the coldest of the weekend, PJM said its operators decided to schedule conservatively in terms of reserves. PJM anticipated approximately 155,700 MW should have been available for Dec. 24, but complications arose from the unanticipated failure of generation resources that were called on that day. At one point, almost a quarter of the generation capacity, 47,000 MW, was on forced outages, the report said.
Across the entire PJM generation fleet, natural gas generators accounted for 70 percent of the outages on Dec. 24, most of them caused by equipment failure likely resulting from the extreme cold with broader issues of gas availability also contributing to the outages, the report said.
Winter Storm Elliott was the first wide-scale use of PJM’s Capacity Performance rules that were introduced in 2016 in the wake of the 2014 Polar Vortex. The high outage rates for generators during Winter Storm Elliott resulted in substantial Non-Performance Charges that are part of Capacity Performance rules.
PJM estimates there are approximately $1.8 billion in Non-Performance Charges based on the current rules, which call for the charges to be allocated to suppliers that exceeded their committed capacity level.
While PJM operators were able to keep electricity flowing in the region throughout the storm “Elliott also provides some clear lessons for PJM and its stakeholders that drive” the 30 recommendations contained in this report,” PJM said.
The recommendations are broadly focused on:
- Addressing winter risk with enhancements to market rules, accreditation, forecasting and modeling;
- Improving generator performance through winterization requirements, unit status reporting and testing/verification;
- Tackling long-standing gaps in gas-electric coordination, including timing mismatches between gas and electric markets, the liquidity of the gas market on weekends and holidays, and the alignment of the electricity market with gas-scheduling nomination cycles;
- Evaluating how the Performance Assessment Interval system of rewarding or penalizing generator performance is impacted by exports of electricity to other regions, whether excusal rules can be simplified, PAI triggers need to be refined, and if the contributions of Demand Response and Energy Efficiency are accurately valued;
- Pursuing opportunities with Generation Owners, other members and states to improve education, drilling and communication regarding PJM’s emergency procedures, Call for Conservation and PAIs.
PJM said many of the recommendations are being developed through the Critical Issue Fast Path–Resource Adequacy process or other forums, including the Electric Gas Coordination Senior Task Force, Operating Committee and Market Implementation Committee.