The Order
The strategic question of the summer of 2026 was arithmetic: could the mid-Atlantic grid keep a region cool and feed its data centers at the same time? As an Associated Press report framed it, the Department of Energy had moved to widen the options on the Tuesday before, granting the regional grid operator, PJM Interconnection, permission to potentially force data centers onto their backup diesel generators as searing temperatures pushed demand toward records.
The broader stakes run through Virginia, the epicenter of the country’s data center boom. Regulators in the state have green-lit over 8,000 diesel generators at data center sites over the past several years, according to Department of Environmental Quality data, and the DOE order would let facilities run them beyond limits for emissions the EPA classes in its possible-human-carcinogen category. The calculus, as PJM describes it, makes generator orders a last resort, coming only after consumers are urged to cut use.
The Numbers Behind It
Demand across PJM’s territory, stretching from Washington to Chicago, was projected to peak around 166 gigawatts Thursday afternoon, beyond the 165 GW all-time mark that has stood since 2006 and far above the 156 GW summer forecast, with an “unlikely but plausible” crest near 169 GW. The National Weather Service put the heat index at 110 degrees in Philadelphia and 112 in the capital. “It’s scary. It worries everyone when you see those kind of numbers,” said Abe Silverman, once a utility regulator in New Jersey, who added that the future is worse: “The projections for data center loads dwarf the amount of data center load we have now,”
Brown University climate scientist Kim Cobb located the pressure in the climate system itself. “This is exactly what we expect in a warming world,” she said, noting that modest baseline warming translates into far more frequent extremes. Energy Secretary Chris Wright, for his part, blamed the prior administration and pledged action: “We are reversing those failures and using every available tool ensuring Americans in the Mid-Atlantic have continued access to affordable, reliable, and secure energy to power and cool their homes,”
The Communities Downwind
The catch is who breathes the difference. One-third of Virginia data centers sit within 500 feet of homes or schools, state auditors found, and Prince William County alone has 33 completed facilities with 31 more coming. Elena Schlossberg, who runs a grassroots group opposing them, put the Fourth of July trade bluntly: “Either way, we are screwed,” “Either our lights go out or we get to breathe in this pollution.”
Ann Bennett of the Sierra Club of Virginia said residents were already emailing about protecting themselves, and her tally of DEQ permits found 3,790 additional diesel generators approved in 2025 alone. The industry’s answer, from Data Center Coalition vice president Aaron Tinjum, was cooperation: facilities “will work closely with utilities and grid operators, using backup power if directed and where appropriate to reduce strain on the grid and ensure Americans and first responders remain connected to the services they rely on.”
The Precedent
DOE issued similar orders before Winter Storm Fern and a May heat wave; PJM never called the generators then. Last June, two Ashburn-area facilities did run on diesel, an event later attributed to a substation fire, but the memory of gray plumes over Loudoun County stuck. What this signals, with demand records falling and thousands of new generators standing by, is that the backup plan and the neighborhood are now the same place.
