One fallen power line exposed a growing AI data center problem. Here’s how to fix it.

This week, a power line went down outside Washington, DC. Normally the grid would only need a few seconds to recover from such an event. But it lasted more than 10 minutes because more than 3 gigawatts of data centers stopped drawing power almost simultaneously.

According to data collected from the event, tension across the PJM grid caused a spike from Northern Virginia to Chicago Ting Labsa startup that runs an IoT sensor network from people’s electrical sockets.

The event did not cause a blackout, but it did cause lights to flicker across the region. The incident demonstrated the effect data centers can have on the power grid – an outcome that experts say will become more common.

Northern Virginia, which is located in PJM territory, is home to the highest concentration of data centers in the world.

“It’s the canary in the coal mine,” says Ricardo de Azevedo, CTO at ON.Energytold TechCrunch. These types of events involving large loads, such as data centers, are happening “increasingly,” he added.

The event mirrors one that occurred two years ago, also on PJM’s power grid, and could foreshadow larger events if data centers are not built to deal with power disruptions more elegantly. The PJM Interconnection operates grids from New Jersey to Illinois and serves 67 million customers, making it the largest grid operator in the United States.

When the power line went down this week, data centers were prompted to switch to backup power. According to data, about 3.1 gigawatts of load disappeared in about 30 seconds. PJM data. The grid seemed to recover somewhat, but a short time later the additional loads decreased. At its peak, PJM’s power grid had an additional 3.49 gigawatts of electricity. It took another 11 minutes for it to stabilize. The disconnected data centers represented approximately 3% of total PJM demand at the time. according to to Reuters.

A few percent may not sound like much, but the electricity grid must function in an almost perfect balance, with supply and demand closely matched. If they don’t, tensions can drop or spike. The electrical grid and the devices connected to it can tolerate small fluctuations, but if these fluctuations become too large, they cause failsafes within the electrical grid or within individual facilities, causing them to become disconnected.

When data centers in Northern Virginia noticed the fluctuations caused by the faulty power line, they switched to backup power, taking their load off the grid. As more data centers made the switch, they removed greater amounts of load from the grid. What started as a relatively small drop in supply became an even bigger drop in demand, causing supply to soar and light bulbs to flicker.

Most data centers make split-second decisions, and the data centers that disconnected this week appear to be no different. When the voltage dip reached them, they all decided to disconnect within a few seconds of each other, Ali Zain Banatwala, senior market modeling specialist at the Independent Electricity System Operator, told TechCrunch.

“We have to figure out a way to sequentially disconnect or reconnect these loads that are next to each other,” he said. A clearer process allows grid operators to develop more robust procedures in advance.

Alternatively, data centers can be built to absorb disruptions and not turn their backs on them. One startup, ON.Energy, has been working on a product to help data centers (and the power grid) with events like this week’s.

The company has developed an uninterruptible power supply for an entire data center campus, covering not only servers, but also chillers and other equipment. The company essentially hides the data center behind a series of batteries connected to sophisticated power conversion equipment. All the network “sees” is one consistent, well-behaved load, rather than the peaks and valleys of each individual part of the data center. ON.Energy’s system allows data centers to scale up and down computing workloads, including AI training, without burdening the electrical grid.

Perhaps more importantly, it also means that data centers can absorb power fluctuations from the electricity grid. Instead of disconnecting from the grid, ON.Energy’s system can use any extra power to charge the batteries, and if the power drops, the system can send power to servers. Additionally, it can track the power grid’s line within milliseconds, preventing fluctuations like the one that caused this week’s problem for PJM.

ON.Energy is currently installing a total of 3 gigawatts of systems on four different data center campuses, de Azevedo said.

Network operators have also become aware of the problem.

ERCOT, for example, will need large loads, such as data centers, to drive through disruptions, De Azevedo said.

However, the clock is ticking. This week’s mass disconnection was twice as large as a similar event in 2024, when 60 data centers were simultaneously disconnected, removing 1.5 gigawatts of load from the grid. At the time, data centers accounted for about 6% of PJM’s load. according to to Synapse Energy Economics. By 2040 this is expected to account for 24%. If the problem is not addressed quickly, things could get much worse.