This week, a power line failure occurred near Washington, DC. Typically, the grid would recover in a few seconds from such disruptions, but this incident took over 10 minutes due to more than 3 gigawatts of data centers ceasing power consumption almost simultaneously.
The incident led to a voltage spike across the PJM grid, stretching from Northern Virginia to Chicago, as reported by data from Ting Labs, a startup utilizing IoT sensors in electrical outlets.
Although the event did not result in a blackout, it caused lights to flicker throughout the region, highlighting the significant impact data centers can have on the grid—an effect experts predict will become more common.
Northern Virginia, part of PJM’s jurisdiction, hosts the largest concentration of data centers globally.
“It’s the canary in the coal mine,” remarked Ricardo de Azevedo, CTO at ON.Energy, to JS, noting that such events involving substantial loads like data centers are “happening more and more.”
This event mirrors one from two years ago on the same grid and suggests potential for larger issues if data centers are not improved to manage power supply disruptions more efficiently. PJM Interconnection, the largest grid operator in the U.S., oversees grids from New Jersey to Illinois, serving 67 million customers.
The power line failure triggered data centers to switch to backup power, causing approximately 3.1 gigawatts of load to disappear in about 30 seconds, according to PJM data. While the grid seemed to partially recover, additional loads soon dropped off. At its peak, PJM’s grid experienced an excess of 3.49 gigawatts of electricity. It took another 11 minutes to stabilize. The disconnected data centers accounted for about 3% of PJM’s total demand at the time, according to Reuters.
While a few percent may seem minor, the electrical grid must maintain near-perfect balance, closely matching supply and demand. Any imbalance can cause voltage sags or spikes, and while the grid and connected devices can handle small fluctuations, significant ones trigger failsafes, leading to disconnections.
When data centers in Northern Virginia detected the fluctuation from the power line failure, they switched to backup power, removing their load from the grid. As more centers followed, the drop in demand intensified, causing a supply surge and light flickers.
Data centers typically make split-second decisions, and those that disconnected this week were no exception. Once the voltage dipped, they disconnected within seconds of each other, explained Ali Zain Banatwala, senior market models specialist at the Independent Electricity System Operator, to JS.
“We need to find a method for these proximate loads to sequentially disconnect or reconnect,” he suggested, proposing that a more organized process could help grid operators develop stronger procedures in advance.
Alternatively, data centers could be designed to handle disruptions without disconnecting. ON.Energy has been working on a solution to help data centers and the grid manage events like this more effectively.
The company has created an uninterruptible power supply for whole data center campuses, covering servers, chillers, and other equipment. This system hides the data center behind a bank of batteries linked to advanced power conversion equipment, presenting the grid with a consistent, well-managed load instead of the individual peaks and valleys of each data center component. ON.Energy’s system enables data centers to adjust computing workloads, including AI training, without impacting the grid.
More importantly, it allows data centers to absorb power fluctuations from the grid. Instead of disconnecting, ON.Energy’s system can charge its batteries with excess power, and if the flow decreases, it can supply power to servers. It can respond to the grid within milliseconds, preventing disruptions like those seen this week on PJM’s grid.
ON.Energy is currently installing a total of 3 gigawatts of its systems at four data center campuses, de Azevedo noted.
Grid operators are also addressing the issue.
ERCOT, for example, plans to require large loads like data centers to “ride through” disruptions, according to de Azevedo.
Time is of the essence. This week’s mass disconnection was twice as large as a similar event in 2024, when 60 data centers disconnected simultaneously, removing 1.5 gigawatts from the grid. At that time, data centers constituted about 6% of PJM’s load, according to Synapse Energy Economics. By 2040, they are expected to account for 24%. If the issue is not resolved soon, the situation could deteriorate significantly.
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