Run your own diesel or risk blackouts: the federal clause Northern Virginia should know about

RICHMOND, Va. - Here is the deal Washington offered the grid serving Northern Virginia in September: big power users run their own diesel generators, and families keep their lights on.

Paragraph B of Department of Energy Order No. 202-26-45, signed Sept. 17 by Energy Secretary Chris Wright, authorized PJM Interconnection to direct backup generation "whether auxiliary, standby, directly-connected, battery storage, or other" to run "as a last resort before declaring an EEA 3 (i.e., before firm load interruption) or during an EEA 3." Paragraph C says the order "requires the operation" of those resources.

PJM asked for exactly that, and it asked that large loads be allowed to run backup generation "notwithstanding any applicable environmental limitations under federal, state, or local law or regulation." Its stated reason was that this "could help the RTO avoid residential load shed at EEA level 3." Residential load shed means cutting power to homes.

What ran in Loudoun

PJM's Sept. 17 compliance report shows six diesel units in Ashburn ran under the order: VA1, VA2 and VA3 for 8 hours each, VA5 for 10, and VA6 and VA10 for 9 hours each. Exhibit A lists their combined nameplate rating at about 98 megawatts. A 30-megawatt diesel unit in Gainesville, CH1, was listed but not reported as running.

The filing does not say who owns the units or what they power. Ownership isn't in the filing, and neither PJM nor DOE has identified them as data centers.

The air and noise question

For Northern Virginia neighbors, the obvious questions are about air and noise. The federal record answers neither.

Exhibit A lists the relaxed constraint for the Ashburn units as "Limitation on emergency engine operation," which caps how long such engines can normally run. Under the order, hours, fuel and emissions during the emergency do not count toward rolling-average limits. Owners still had to monitor and keep records "to the maximum extent practicable," and normal rules resumed after Sept. 18.

The compliance report lists run hours only. It gives no emissions data, no output and nothing on noise. The Virginia Department of Environmental Quality permits stationary engines, and Loudoun County sets local noise rules. Any detailed records would sit with them or the owners.

The conservative case for the clause

Diesel isn't anyone's idea of clean air. But the alternative on the table was rolling blackouts, with no air conditioning in a heat wave, no refrigeration, and no power for medical devices at home. The order spared the generators that matter most for public safety. Backup units at hospitals, 911 centers, water and wastewater plants, defense and first-responder sites, air traffic control and gas pipelines were exempt.

Large private users who paid for their own backup took the load off the public grid for a day. That is a sensible emergency valve. It's also an admission that the grid didn't have enough power on its own.

How it got here

PJM told DOE it expected demand near 133,285 megawatts on Sept. 17 and a shortfall of about 700 megawatts below its reserve margin, with strain worst in the BGE, Pepco and Dominion zones. About 33,191 megawatts of generation was out, much of it for fall maintenance. That morning, a plant serving those zones went offline unexpectedly, and PJM hasn't named it.

The backup-generator clause follows a Jan. 22, 2026, letter from Wright urging grid operators to plan for backup generation in emergencies. PJM cited seven earlier 2026 orders using similar authority. Backup units used under the order are not counted as capacity resources, so ratepayers aren't charged for them through PJM's capacity market.

The question for Richmond

If Northern Virginia neighborhoods are going to hear diesel engines whenever the grid gets tight, residents deserve to know why the grid keeps getting tight. PJM's answer for September was heat, maintenance outages, transmission limits and exports. Richmond's answer has yet to come.

Documents

The order, PJM's application, its supplemental letter and Exhibit A are posted on the Department of Energy's 202(c) page for Order No. 202-26-45 at energy.gov. PJM's daily compliance report for Sept. 17 is posted at pjm.com.