Breaking: Data Centers Strain PJM Grid as Shoulder Season Relief Vanishes

The U.S. Department of Energy declared a power grid emergency across 13 states and the District of Columbia, granting PJM Interconnection temporary authority to stabilize the regional grid from October 13 through October 16, 2026. Energy Secretary Chris Wright issued the order on Sunday, October 12, under section 202(c) of the Federal Power Act. This action was not a prediction of scheduled blackouts but a proactive measure to prevent interruptions. For households and businesses in the affected region, daily electricity use remained normal, and no mandatory conservation orders were issued. The emergency was driven by a fundamental shift in how electricity is consumed, where the traditional relief of the fall shoulder season has largely disappeared due to the relentless demand from data centers.

PJM Interconnection coordinates wholesale electricity for approximately 67 million people across all or parts of Delaware, Illinois, Indiana, Kentucky, Maryland, Michigan, New Jersey, North Carolina, Ohio, Pennsylvania, Tennessee, Virginia, West Virginia, and the District of Columbia. If your home or business is located outside these 13 states and the District of Columbia, the order did not cover your area. For those within the PJM footprint, the situation required technical management by grid operators rather than immediate action by consumers. The primary driver of this strain was the collision of unseasonably warm October weather with the period when generator and transmission owners typically take equipment offline for maintenance.

Historically, the shoulder season offered a reprieve because demand dropped as temperatures cooled. However, PJM states that this reprieve is not what it used to be. The new reality is defined by data centers and other energy-intensive large-load customers. Their consumption is a 12-month, 24/7 phenomenon that does not fall with the weather. This expanding demand is outpacing new transmission and electricity supply coming onto the system. When unseasonably hot or cold weather now arrives outside the traditional peak seasons, the grid faces unprecedented pressure because the baseline load remains high regardless of the temperature.

On Friday, October 9, PJM issued a Capacity Advisory for Monday, October 12, and Tuesday, October 13. This marked the first ever use of that procedure, which PJM members endorsed in June 2026 for circumstances indicating an approaching capacity shortfall. The load forecast was about 102,000 megawatts of peak demand on Monday and about 104,000 megawatts on Tuesday. This demand stood against previously scheduled generation outages of about 70,000 megawatts plus planned transmission outages. Paul Dajewski, PJM’s senior manager for dispatch, told stakeholders that this volume of outages is typical for the shoulder season, but the high demand levels created a tight operational window.

The Department of Energy order allowed PJM to call on generators to run in excess of their operating permits as needed. Crucially, it empowered PJM to direct data centers and other large electricity users onto their backup generation if necessary. The Department of Energy said PJM wanted to deploy auxiliary, standby, directly connected, battery storage, or other generation resources at data centers, including hyperscaler facilities, and at other large industrial and commercial customer sites. This specific authority was designed to ensure that the steady, round-the-clock load from these facilities could be managed without disrupting the wider grid.

On Monday, October 12, PJM issued a Maximum Generation Alert and a Load Management Alert for October 13. A Maximum Generation Alert tells transmission and generation owners that conditions will be tight so they can defer or cancel equipment maintenance and testing. It also informs neighboring grid operators that exports from PJM may be curtailed. PJM extended the Capacity Advisory through October 14 and issued a Maintenance Outage Recall for that date after forecasting demand of approximately 111,500 megawatts or higher. On October 13, PJM extended the alerts and called on Demand Response. These are programs that pay customers who sign up in advance to cut electricity use when the grid is stressed.

Scheduled transmission line outages also limited how much electricity could move between zones. Generation was bottled in some areas because of transmission limits, particularly resources serving congested zones in Washington D.C., Maryland, and Virginia. These areas include the BGE, Pepco, and Dominion zones. PJM had also used Department of Energy emergency orders during two unseasonably warm September periods, from August 31 to September 4 and September 15 to 18, to let eligible resources keep operating beyond normal limits. After sunset on those days, PJM had to cover net load as solar output fell faster than electricity use.

As of the PJM Winter Outlook released on November 5, 2026, the grid operator expects sufficient resources to reliably meet demand this winter under expected conditions. However, reserve margins continue to tighten as demand outpaces new supply. PJM expects 182,426 megawatts of operational capacity to serve a forecast winter peak of approximately 147,500 megawatts, plus about 3,200 megawatts of average exports to neighboring systems. That peak, driven by demand growth, would set a new winter record if reached.

Reliable winter operations depend on strong generator performance during extreme cold, especially where transmission constraints limit deliveries. Michael Bryson, PJM’s senior vice president of operations, said, “Our goal is to coordinate operations with the generation and transmission owners and proactively manage the system to perform at high levels when consumers need energy the most.” The integration of data centers into the grid’s operational planning highlights that the modern power system must now account for constant, weather-independent loads that were previously negligible in seasonal planning.