PJM heat emergency: when the grid is the kill switch
As 160 million Americans swelter under a record heat dome, the U.S. energy secretary declared an emergency for PJM, the nation's largest grid, authorizing actions to prevent blackouts. The scenario that haunts reliability planners, a multi-day blackout during extreme heat, is the one that kills thousands.
The Department of Energy declared an emergency for PJM Interconnection this week, as a heat dome settled over the eastern U.S. and 160 million people faced temperatures above 100°F.[1] The order lets PJM take extraordinary steps to keep the lights on. That is the right call. But it is also a reminder of what happens when those steps fail.
Peer-reviewed modeling of a multi-day blackout during a Phoenix heat wave projects roughly 13,000 deaths, because indoor temperatures in unconditioned homes cross survivability thresholds within hours, and nearly everyone depends on air conditioning. PJM serves Washington, D.C., and parts of 13 states, including cities like Philadelphia and Baltimore that saw triple-digit heat this week.[1][3] The same physics applies. The same mortality risk exists.
Heat kills more Americans than any other weather, and a large share of those deaths happen indoors, in homes with air conditioning present but unaffordable to run or disconnected. The utility's shutoff ledger and the medical examiner's ledger describe the same event. During a heat emergency, every disconnection is a potential death sentence, and only about 20 states plus D.C. have any summer shutoff protection at all.
The emergency declaration reveals a deeper imbalance. LIHEAP, the federal utility-bill safety net, was built for a colder century: cooling assistance remains optional for states and is dwarfed by heating aid, even as heat now kills more Americans than cold. The grid is being asked to carry record loads driven by data centers and AI,[5] while the households most vulnerable to disconnection are left without a dedicated survival program.
Every reliability docket, load-shed plan, and hardening request in an extreme-heat metro should be scored against the blackout-heatwave scenario. Ask your utility directly: what does your load-shed sequencing do to residential air conditioning in July? The answer, in an emergency, is the difference between a managed event and a mass-casualty event.
[1] 'Stretched to the limit': Heat wave prompts US electrical grid emergency
[2] Heatwave disrupts Fourth of July events across US, strains power grids
[3] America's 250th birthday hit by extreme heat wave, storm threat disrupts July 4 plans
[4] Extreme heat wave in its final stretch and could fuel storms ... - CNN
[5] US heatwave to test power grid amid soaring AI-driven energy demand