One downed power line flickered lights from Virginia to Chicago. AI data centers caused it.
When a single transmission line failed near Washington, DC, more than 3 gigawatts of data center power vanished in seconds. The grid took 11 minutes to recover. It's a warning of what comes next as AI demand keeps climbing.
Key points
- A power line failure near Washington, DC this week sent 3.49 gigawatts of surplus electricity surging onto the PJM grid, the largest grid operator in the United States, serving 67 million customers.
- About 3.1 gigawatts of data center load disconnected within 30 seconds, causing voltage to spike from Northern Virginia all the way to Chicago.
- The mass disconnection was roughly twice the size of a similar event in 2024, when 60 data centers pulled 1.5 gigawatts from the grid at once.
- Data centers made up about 6% of PJM's total electricity demand in 2024; analysts expect that share to reach 24% by 2040.
- Startup ON.Energy is installing 3 gigawatts of battery-based stabilisation systems across four data center campuses.
A single power line fell near Washington, DC this week. Normally the grid recovers in seconds. This time it took more than 11 minutes, and for a stretch of that time lights flickered across the eastern United States as far as Chicago.
The culprit was a decision made simultaneously by dozens of data centers in Northern Virginia.
What actually happened?
When the line failed, voltage on the PJM grid, which manages electricity from New Jersey to Illinois, dipped briefly. Data centers are engineered to shield their equipment from exactly that kind of wobble, so within seconds they switched to backup generators and cut their connection to the public grid. The problem: they all did it at once.
About 3.1 gigawatts of demand, roughly the output of three large nuclear reactors, vanished in around 30 seconds, according to PJM data. The grid, suddenly supplying far more power than anyone was drawing, spiked to 3.49 gigawatts of surplus. That surge sent voltages rippling across the region. First reported by TechCrunch, the event was measured by Ting Labs, a startup that tracks grid health through sensors plugged into ordinary electrical sockets.
Why does this keep happening?
The grid must stay in near-perfect balance. Supply and demand have to match closely, or voltages swing. Small swings are tolerable. Large swings trigger automatic safety systems inside the grid and inside individual buildings, which then disconnect to protect themselves.
Northern Virginia holds the highest concentration of data centers anywhere in the world. When one senses a voltage dip, they all do, and they respond within seconds of each other.
"We need to figure a way for these loads that are located next to each other to sequentially either disconnect or reconnect," Ali Zain Banatwala, a senior market models specialist at the Independent Electricity System Operator, told TechCrunch.
This week's cascade was about twice as large as a similar episode two years earlier, when 60 data centers simultaneously pulled 1.5 gigawatts from the grid. We flagged the broader trajectory in July when we reported that data centers could consume a fifth of all U.S. Electricity by 2035; this week's event is what that trajectory looks like on a Tuesday morning.
| Event | Year | Load dropped | Recovery time |
|---|---|---|---|
| Northern Virginia cascade | 2024 | 1.5 GW | Not disclosed |
| Northern Virginia cascade | 2025 | 3.1 GW | 11+ minutes |
| Data centers' share of PJM load | 2024 | ~6% | |
| Projected share of PJM load | 2040 | ~24% |
What is the fix?
One answer comes from ON.Energy. The startup wraps an entire data center campus behind a large bank of batteries and smart power-conversion equipment, so the grid sees one steady, well-behaved customer instead of a cluster of machines that can vanish in a heartbeat.
When grid power dips, the batteries fill the gap in milliseconds, so the data center never needs to disconnect. Surplus power gets absorbed by the batteries. ON.Energy is fitting its systems across four data center campuses totalling 3 gigawatts of capacity, according to chief technology officer Ricardo de Azevedo, who told TechCrunch: "It's the canary in the coal mine."
Texas's grid operator, ERCOT, plans to require large customers like data centers to ride through disruptions rather than disconnect, de Azevedo said. That kind of mandate may be the faster path to a solution than waiting for voluntary coordination.
If you run a business near a data center hub, or you simply noticed the flicker, the underlying problem is coordination, not catastrophe. But it gets harder to manage every year that AI training adds more load. Asking your local utility what it's doing about large industrial disconnections is a completely reasonable question right now, and worth asking before the next line falls.
