PJM has issued a Cold Weather Alert for the ComEd service area for Dec. 13 and for PJM’s Western Region for Dec. 14 and 15 ahead of expected frigid weather in those areas this weekend and into Monday.
A Cold Weather Alert is a routine procedure PJM issues in advance of significantly cold weather conditions expected for all or parts of the region PJM serves. Low temperatures are expected to reach single digits in the ComEd region on Saturday, which includes Chicago and other parts of northern Illinois, and expand to the western portion of PJM on Sunday and Monday.
When issued, PJM communicates with generation owners to tell them to be prepared to call in additional staff to get all units running for when electricity use begins to increase. Generation owners must take extra care to maintain equipment so that it does not freeze in the cold and are reminded to provide updated information to PJM on limitations to their units, including time required to start and the max and min times that their units can run once started.
A Cold Weather Alert can also be used to defer or reschedule planned generation maintenance outages and/or transmission outages and/or recall transmission/generator outages, if necessary.
The Western Region in PJM is made up of the following transmission zones and control areas:
- AES Ohio – formerly Dayton Power & Light
- American Electric Power (AEP Ohio, Appalachian Power, Indiana Michigan Power and Kentucky Power)
- American Municipal Power Transmission
- ComEd
- Cleveland Public Power
- Duke Energy Ohio and Duke Energy Kentucky
- Duquesne Light Company
- East Kentucky Power Cooperative
- FirstEnergy South – formerly Allegheny Power Systems (West Penn Power, Mon Power, Potomac Edison)
- FirstEnergy West – formerly American Transmission Systems, Inc. (Penn Power, Ohio Edison, The Illuminating Company and Toledo Edison)
- Ohio Valley Electric Corporation
PJM Winter Preparations
PJM expects to have 180,800 MW of winter operational capacity to serve its seasonal forecast peak demand for this winter. This expectation is based on PJM and the PJM resources continuing to take operational steps to improve generator performance during extreme winter conditions.
PJM has added approximately 4,800 MW of new generation (nameplate capacity) since last winter, most of it solar; that translates to approximately 1,000 MW more operational capacity for the 2025–2026 winter.
To develop its winter scenario forecasts, PJM analyzes expected electricity demand, weather predictions and other factors. The National Weather Service predicts a slightly warmer winter for the Atlantic seaboard, with typical temperatures – but above-average precipitation – in PJM’s midwestern states of Illinois, Indiana, Kentucky, Michigan and Ohio.
PJM and stakeholders take a number of actions to prepare for cold weather, outlined in its Cold Weather Preparation Guideline and Checklist, contained in Manual 14D, Attachment N. These protocols incorporate lessons learned from past severe events, including Winter Storm Elliott (2022), Winter Storm Uri (2021) and Winter Storm Enzo (2025).
Read more about PJM’s winter operations preparations.