Operations
Operations Improvements See PJM Through Record Peaks Amid Changing Resource Mix and Growing Demand
PJM maintained reliability through peak weather conditions and growing demand amid tightening reserve margins.
As 2025 began, PJM’s generation and transmission fleet supported reliable operations and reached new winter demand records during a week-long January freeze. An Arctic outbreak that started Jan. 18 brought single-digit temperatures to much of the region PJM serves and neighboring grids.
By Jan. 22, PJM demand rose to an hourly peak of approximately 143,858 MW between 8 a.m. and 9 a.m. At the same time, PJM kept exporting 8,000 MW to support surrounding grid stability. This peak performance surpassed PJM’s prior all-time cold season record of 143,434 MW set in 2015. PJM also served its fifth-highest and sixth-highest winter loads on Jan. 21 and Jan. 23, the last of the six-day event.
PJM Top 6 Winter Peaks
PJM’s reliable operations were made possible by improved preparations for wintry weather and notable collaboration between PJM and Member companies.
Actions taken included:
New Winter Preparedness Measures
PJM entered the winter of 2025/2026 with an operational capacity of 180,804 MW, a slight decline in available resources from the year prior but sufficient to meet reliability standards. In October 2025, new cold weather readiness standards for generators formulated by the North American Reliability Corporation (NERC) became effective. NERC oversees reliability for the grid operators in North America on behalf of the Federal Energy Regulatory Commission (FERC).
The new mandatory NERC standards require that generation resources:
- Implement freeze protection measures and other steps to prepare units for winter.
- Disclose any operational constraints that impact their operations in freezing weather to dispatching grid authorities and submit corrective action plans for such constraints. This information enhances PJM’s existing database of minimum operating temperatures for each of the resources in its generation fleet.
Beyond new mandatory standards, PJM has long required generators to follow a specific mandatory cold weather checklist and is constantly improving winter preparedness. Steps like these enhance collaboration with, and readiness of, critically needed generation during extreme cold:
Milestone Summer Performance
When temperatures soared at the other end of the thermometer in the summer, PJM kept air conditioners and fans going for the 67 million people in its footprint. The early summer heat wave, June 22–26, gave rise to PJM’s third- and fifth-highest all-time summer peaks, approximately 161,297 MW and 160,941 MW, respectively, on June 23 and June 24. The July 29 peak load of approximately 156,402 MW was the tenth highest.
PJM Top 6 Summer Peaks
While using available generation, PJM tempered late afternoon electricity demand by calling on customers who receive compensation in exchange for trimming power use. These customers are enrolled in load management, or Demand Response (DR) programs, to reduce load during critical periods. In all, PJM initiated six load management events during the summer.
Major Substation Failure Prompts Coordinated Response To Avert Widespread Outages and Limit Load Shed
PJM operations’ response to a predawn critical substation outage on Aug. 11 mitigated the risk of up to 1,200 MW of load loss around Baltimore, Maryland. As equipment failures multiplied in the dawn hours, PJM implemented emergency procedures in the BGE transmission zone and recalled to service some generating units from maintenance outages.
Operating Events: Brandon Shores
(Aug. 11, 2025)
Daylong relief measures included a call on all DR resources in the BGE zone. As studies showed risk of widespread urban outages near the afternoon peak, PJM initiated a Load Shed Directive to interrupt approximately 20 MW of system load for 28 minutes.
Solar Additions Highlight Changing Resource Mix
Contributions by solar resources serving PJM energy needs reached an all-time PJM high on April 18 of nearly 12,000 MW. This growth in solar output coincided with continuing solar growth in the PJM fleet. In 2025, PJM added:
This growth underscores the ongoing evolution of PJM’s resource mix, with solar accounting for the majority of new capacity additions and contributing to greater diversity in generation resources across the region.
Preparedness for Peak Conditions and Load Growth
PJM coordination with Member generation and transmission owners was enhanced in many ways during 2025.
Actions included:
Expanded Demand Response Availability
PJM expanded its DR availability window to 24 hours daily. This change improves grid reliability by including DR resources during all hours of risk and takes effect for the 2027/2028 Delivery Year.
Expanded Transmission Outage Studies
PJM broadened study and coordination of the operational impacts of required transmission outages to support placing Regional Transmission Expansion Planning (RTEP) upgrades in service. PJM operations now models substations and facilities for up to two years in the future to identify and mitigate conflicts caused by major transmission construction required by growing demand and generator retirements, particularly in the AEP, BGE, PEPCO, FE South and Dominion transmission zones.
Improved Readiness of Inverter-Based Resources
In May, PJM issued an alert (PDF) to communicate critical readiness actions to prepare inverter-based resources for use during peak operations. Actions included required unit adherence to NERC reliability standards and PJM manual steps and procedures to ensure grid reliability.
Created Wildfire Procedure
PJM stakeholders endorsed a Manual 13 revision to create the first PJM Wildfire Procedure. This codifies coordination and preventative measures PJM undertakes with transmission owners prior to and during wildfire events.
U.S. Department of Energy 202(c) Orders
PJM supported U.S. Department of Energy (DOE) orders to defer retirements of select dispatchable generation units in light of growing resource adequacy concerns.
- DOE directed the continued operation of Constellation’s Eddystone Generating Station Units 3 and 4, both 380 MW steam plants in Pennsylvania, past their previously planned retirement dates.
- A DOE order approved a PJM request and directed Talen-owned Wagner Unit 4 in Maryland to run beyond emissions limits during reliability emergencies to help maintain voltage stability and prevent thermal overloads.
PJM collaborated with stakeholders to arrive at unit cost allocation rules to support continued operations of these facilities, rules that were approved by FERC later in the year.
Throughout the year, PJM continued efforts to assist stakeholders, states and unit developers in overcoming hurdles beyond its control to bring dispatchable generation online.
Storage as a Transmission Asset
PJM picked up stakeholder work on how to integrate storage facilities as transmission assets into PJM operations. This work continues in the stakeholder process and is expected to enhance needed flexibility for PJM Dispatch.
GridEx VIII
PJM practiced systemwide crisis response at the semiannual GridEx drill event Nov. 18–20. The exercise drew industrywide participation and direct participation or observation by representatives from six states.