A record-setting September heat wave pushed the nation’s largest electric grid close enough to the edge that federal regulators stepped in to order emergency backup generation online. The order, issued by the Department of Energy for the grid operator covering roughly 67 million people from the mid-Atlantic to the Midwest, came as extreme temperatures across dozens of states drove demand for power to levels that left little margin for error.
The Grid Under Strain
PJM Interconnection manages the electric grid serving a stretch of the country running from Washington, D.C. through Chicago, making it the largest regional transmission organization in the United States by population served. As temperatures climbed in early September 2026, demand across that footprint rose sharply enough that PJM issued a maximum generation emergency alert, a formal signal used to direct power plant operators that are on planned outages to report how quickly they could bring their units back into service.
That step is one of several PJM can take before conditions deteriorate to the point of ordering rotating outages, and it reflects how closely operators were watching the balance between available generation and rising demand as the heat wave settled over the region. Late-season heat waves of this magnitude are historically harder for grid planners to manage than midsummer peaks, since some generating units are already offline for scheduled maintenance heading into autumn.
The Federal Emergency Order
On September 1, PJM filed an emergency application with the Department of Energy under Section 202(c) of the Federal Power Act, the legal authority that allows the federal government to direct specific power plants to operate during a grid emergency. Energy Secretary Chris Wright approved the request, authorizing PJM to direct backup generation resources to run as a last resort ahead of, or during, an Energy Emergency Alert Level 3, the alert tier that sits just before utilities would need to begin rotating blackouts to protect the broader system.
The order gave PJM authority to dispatch particular generating units and keep them running through the peak of the heat event, a mechanism intended to add reserve capacity to the grid without waiting for conditions to worsen into an active blackout scenario. According to Insurance Journal, the order marked one of the more significant recent uses of that federal authority to intervene directly in a regional grid’s operations, and it followed a similar pattern the Department of Energy has used in prior PJM heat events earlier in 2026.
How Close the System Came to Rotating Blackouts
An Energy Emergency Alert Level 3 is the step immediately preceding controlled, rotating outages, which utilities use as a last-resort tool to prevent an uncontrolled collapse of the broader grid when demand outstrips available supply. PJM’s alert level during the heat wave stopped short of that final tier, but the sequence of escalating alerts, from the initial emergency declaration through the maximum generation alert to the federal backup-generation order, illustrated how narrow the operating margin had become across the system during the hottest days of the event.
Grid operators generally treat the gap between a Level 1 alert and a Level 3 alert as the difference between managing a tight but stable system and actively working to avoid forced outages, which makes the specific sequence of alerts a useful measure of how serious a given heat event turned out to be for grid reliability. In this case, the federal order appears to have provided enough additional generating capacity that the system avoided escalating to the point where utilities would have needed to cut power to customers on a rotating basis.
A Heat Wave Spanning Much of the Country
The strain on PJM’s system did not happen in isolation. At the time the emergency order took effect, roughly 160 million people across 30 states were under some form of alert for extreme heat, according to ABC News. That scale of coverage meant utilities well beyond PJM’s footprint were also managing elevated demand simultaneously, which reduces the ability of neighboring grid operators to send extra power across regional interties during a shortfall, a resource-sharing mechanism grids often lean on during localized emergencies.
With so much of the country under heat alerts at once, the usual cushion that comes from borrowing power across regional boundaries was thinner than it would be during a more localized event, adding to the pressure on PJM specifically to secure generation from within its own footprint rather than counting on outside help. That dynamic is part of why federal officials framed the backup-generation order as a precautionary step rather than a response to an active shortfall, since the goal was to keep the system’s reserve margin from eroding further as the heat persisted.
Why This Kind of Order Is Becoming More Common
Federal emergency generation orders under Section 202(c) were once a rare tool, reserved for unusual circumstances such as storm damage or fuel shortages. Their more frequent use during heat waves in recent years reflects a combination of factors that grid planners have flagged repeatedly: aging power plants retiring faster than new firm generation is being added, rising demand from data centers and electrification, and heat events that push summer peak demand higher than the system was originally designed to handle. PJM’s order was set to remain in effect through September 8, giving operators a defined window to lean on the additional generation capacity before the emergency authority expired, at which point PJM will need to rely on its normal operating reserves unless another extreme weather event prompts a fresh request.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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