PJM calls demand response, cancels outages amid September heat

Solmar Insights

PJM Interconnection triggered both Emergency and Pre-Emergency Demand Response protocols across substantial portions of its grid on September 17, 2026, in response to an unexpected September heatwave and corresponding strain on supply. With load forecasts rising to 132,000 MW and 36,000 MW of generation capacity already offline for maintenance, the grid operator also recalled or canceled additional outages to keep critical infrastructure in service.

Demand response across the footprint

PJM issued system-wide calls for both Pre-Emergency Demand Response and, in select utility service areas, Emergency Demand Response to shore up reserve margins during the evening peak on September 17. These measures were implemented in all but ComEd and the Mid-Atlantic Zones for pre-emergency resources, with emergency response extending to BGE, PepCo, and Dominion service areas. Demand Response participants are compensated upfront and reduce electricity use when grid conditions tighten, offering PJM a flexible, dispatchable tool to alleviate system stress without additional generation.

The move reflects the increasing reliance on customer load flexibility in modern grid operations, especially as weather-driven volatility intersects with long-standing schedules for planned maintenance. The targeted approach, by zone, enables PJM to adjust resources where needed most, coordinating responses across utilities with diverse infrastructure challenges.

These demand-side actions supplement PJM’s standard reserve procurement and serve as a stopgap to minimize customer disruptions while maintaining operational reliability during rare high-load periods outside of typical summer peaks.

Maximum generation and load management alert

Concurrently, PJM issued a Maximum Generation / Load Management Alert throughout its territory. This protocol formally requests that transmission owners and generators defer or cancel scheduled equipment maintenance and testing to keep as much generation and grid capacity available as possible. Deferral helps avoid the risk of additional forced outages during already constrained grid conditions.

This alert also serves as notification to neighboring system operators that electricity exports from PJM may be limited or curtailed, a measure PJM expected to enforce on September 17. With high temperatures affecting not only PJM’s footprint but also neighboring systems to the south and west, regional demand for exports increased, escalating system-wide pressures.

The coordinated rollback of outages and push for maximum generation output forms a critical layer of defense against both physical equipment limitations and surging load profiles, highlighting the challenge of balancing seasonal maintenance with climate-driven heat events in mid-September.

DOE emergency order: environmental and load flexibility

On top of operational responses, PJM secured an emergency order from the U.S. Department of Energy effective through September 18. The order provides temporary exemption from certain environmental permitting restrictions for generating units, authorizing them to operate longer or at higher output when needed, despite emissions limits.

Importantly, the emergency authority also grants PJM the power to direct large load resources, including data centers and heavy industrial customers, to switch to backup generation if required. This helps reduce demand on the main grid, freeing up system capacity during acute load events without disrupting critical digital infrastructure operations.

Such federal interventions are rare and reserved for circumstances where grid reliability is at acute risk and standard operating flexibilities are insufficient. It underscores both the seriousness of the weather event and the ongoing challenge posed by simultaneous outage schedules and extreme weather patterns.

Heatwave timing and outage season dynamics

The timing of the heatwave presents a particular operational challenge for PJM, as September typically marks the start of “outage season” when transmission and generation asset owners schedule critical maintenance and upgrades. From mid-September through December, utilities and generators target this window to ensure full availability for winter and next summer’s anticipated peaks.

With approximately 36,000 MW of generation already out for such work, PJM’s recall and cancellation of further outages represents a substantial deviation from normal procedure but was deemed necessary to safeguard reliability. Even so, many assets remained out for work that cannot be rescheduled, tightening reserve margins and raising the stakes for dispatch decisions and demand-side flexibility.

The incident illustrates the fine balance ISOs must strike between ongoing asset health, regulatory compliance, and adaptive response to climate-driven events. The interplay between maintenance cycles, environmental constraints, and emergency operations will continue to shape grid management strategies, particularly as abnormal weather increases in frequency and severity.

Market impacts for buyers and operators

The events of September 17, 2026 highlight how operational constraints and weather volatility can drive short-term resource scarcity and price swings across the PJM region. Market participants, especially institutional buyers and developers, face heightened risk of curtailment or emergency program participation when unplanned weather events coincide with planned outages.

Authorization for data centers and industrial sites to switch to backup generation further emphasizes the need for contingency strategies, both operationally and contractually. Energy managers and infrastructure operators must factor in not only the frequency of maximum generation alerts, but also the potential for federal emergency orders impacting environmental compliance and facility scheduling.

This episode demonstrates that outage season is not immune to volatility, and buyers seeking power or interconnection capacity must adjust planning windows, cost projections, and reliability expectations to account for flexible system management in both peak and shoulder months.

Reporting via the original publisher