A Virginia line outage exposed how concentrated data-center load can jolt PJM

PJM said it registered a change in grid frequency but no impact on reliability. Dominion said its operations team stabilized the system within minutes. Those facts are important limits on the story: the reporting does not identify the affected operators, their protection settings, or a particular data-center design that failed.

The disturbance was nevertheless visible outside the immediate area. Ting Labs, a company that runs a network of 1.4 million household electrical sensors, recorded voltage disturbances along the eastern United States and as far as Chicago, according to the local report. Its chief executive, Bob Marshall, said the sensor evidence showed correlation with the data-center event but stopped short of claiming causation. That makes the sensor network evidence useful for the disturbance’s reach, not independent proof of its mechanism.

The scale is also not entirely without precedent. The same analysis says 60 data centers simultaneously disconnected in 2024, removing 1.5 GW of load. The initial 3.1-GW loss reported for this event was therefore a little more than twice that earlier load loss. It also cites a Synapse Energy Economics projection that data centers’ share of PJM load could grow from about 6% in 2024 to 24% by 2040—a projection, not an observed forecast result.

ERCOT’s February presentation depicts proposed voltage ride-through conditions for large electronic loads; it was not a rule governing the Virginia facilities. Source: ERCOT ride-through requirements presentation.

More capacity would not by itself control this behavior

Generation and transmission additions address whether the region can supply data centers in ordinary conditions. They do not prescribe what a campus does when voltage deviates. The immediate policy and engineering choices described in the reporting are narrower:

• Arrange disconnection and reconnection so nearby large loads do not act simultaneously.
• Build campuses to remain connected through specified disturbances, using power electronics and batteries where appropriate.

The second approach is a potential commercial product, not a demonstrated solution to this incident. ON.Energy says its campus-scale uninterruptible-power system covers servers, chillers and other equipment by placing batteries and power-conversion equipment between a campus and the grid. Ricardo de Azevedo, the company’s chief technology officer, told the publication that ON.Energy is installing 3 GW of such systems across four campuses. The supplied reporting does not establish the systems’ cost, customers, or performance in a comparable fault.

ERCOT’s February presentation offers a more concrete example of the regulatory direction under consideration elsewhere. It defines a “Large Electronic Load” as a site with at least 75 MW of peak demand, at least half of it power-electronic computational load such as data centers or cryptocurrency mining. Its proposed ride-through requirements would require such loads to remain connected during defined voltage conditions, while allowing different treatment outside those bounds. The presentation says the aim is to mitigate risks seen in Northern Virginia events. It is evidence of a proposed approach in Texas, not a rule that governed the Virginia facilities.

The next question is who controls the response

The public record establishes that a large, concentrated load disappeared rapidly after a local transmission problem and that the system recovered without a reported reliability impact. It does not establish how much of the lost load could safely have stayed online, whether the facilities used common settings, or which actor had the authority to coordinate their behavior.

PJM, Dominion and the affected campus operators will need those answers to choose between common ride-through requirements, coordinated transfer protocols, changes to utility protection, or some combination. The central test is no longer only how many new megawatts the region can serve. It is whether the grid and the facilities connected to it have agreed on what happens during the next voltage disturbance.