
Key takeaways
- Thousands of GPUs training one AI model can raise or drop their power draw in milliseconds, all at once.
- Events in Northern Virginia show that large data center loads can disconnect together and behave like part of the grid.
- NERC has issued a rare Level 3 alert asking utilities to model, monitor and commission these loads differently.
- On-site batteries and workload-aware software are the leading ways to smooth the swings.
Here is a fact that sounds made up but is not. During big TV moments in Britain, like the end of a World Cup penalty shootout, millions of people get up at the exact same second and put the kettle on. Grid engineers call this "TV pickup." For a few minutes, the country's entire power demand jumps by enough to require a small power plant's worth of extra electricity, all because everyone wanted tea at once.
AI data centers have discovered their own version of this trick, except instead of millions of kettles, it is tens of thousands of graphics chips, and instead of happening during penalty kicks, it happens constantly, all day, every day, in bursts that last milliseconds instead of minutes. Engineers have a less charming name for it than TV pickup. They call it an AI load transient. And it is quietly becoming one of the more interesting problems in modern electricity systems.
This post is a plain language tour of what that phrase means, why it happens, and why utility companies have started losing sleep over something as nerdy as how GPUs talk to each other.
What Is an AI Load Transient, Actually
Strip away the jargon and a load transient is just a fast, big swing in how much electricity something is using. Your toaster is not a load transient. It draws a steady amount of power for two minutes and then it is done. A single data center training a giant AI model is a different animal entirely.
Picture a warehouse packed with tens of thousands of GPUs, which are the specialized chips that do the heavy math behind AI models. During training, these chips are supposed to work as one giant team. For a fraction of a second, they are all crunching numbers at full power, pulling as much electricity as they can get. Then they all pause at once to compare notes with each other. During that pause, power use can fall off a cliff.
Multiply that pattern across an entire building full of chips and you get power demand that looks less like a smooth hill and more like a seismograph during an earthquake. One well cited estimate puts the swing at up to 70 percent of total power, and it can happen within milliseconds. At the largest AI facilities, the swing can reach a full gigawatt, which is roughly the output of a nuclear reactor, and it can happen several times a minute.
That is the whole idea in one sentence. An AI load transient is a sudden, massive, repeated swing in electricity demand caused by thousands of computer chips changing what they are doing at almost exactly the same moment.
Why Thousands of Chips Decide to Nap at the Same Time
The reason this happens comes down to how AI training actually works, and it is a bit like a marching band.
A marching band only looks good if everyone steps at the same time. If one trumpet player is half a beat behind, the whole formation falls apart. AI training clusters work the same way. Thousands of GPUs are given pieces of a giant calculation to work on. Once they finish their piece, they have to wait for every other GPU to finish theirs before the whole group can move to the next step.
This synchronizing step even has an official name, AllReduce, which sounds like a discount at a grocery store but is really just the moment where all the chips compare their work and agree on the answer.
During the busy computing part, every chip is pulling maximum power. During the waiting part, most chips are sitting nearly idle. Multiply that by tens of thousands of chips switching between busy and idle in lockstep, and you get power demand that spikes and dips like a heartbeat monitor.
Meta ran into this directly while training its LLaMA 3 model. In its own technical report, the company noted, almost as a side comment, that tens of thousands of GPUs can increase or decrease their power draw at the very same instant. That is not a bug. It is simply what happens when you build the world's most expensive, most synchronized study group.
Two other habits make this worse. The first is checkpointing. Training a giant AI model can take weeks, so engineers regularly save a snapshot of progress, the same way a video game autosaves before a tough boss fight. When a save happens, the entire cluster can drop to almost no power use for a moment, then snap back to full power once the save is done.
The second habit is simpler. When a massive training run finishes and nothing new is queued up to replace it, demand for tens of thousands of chips can vanish almost instantly, like a stadium crowd leaving the moment the final whistle blows.
None of this would matter much if power grids could react just as fast. They cannot. A traditional power plant can only ramp its output up or down by a modest amount each minute. AI chips can ramp their power draw up or down within a few thousandths of a second. It is like asking a cruise ship to keep pace with a jet ski.
Real Places Where This Has Actually Happened
This is not just a theory that lives in engineering papers. It has already caused real headaches at real facilities.
The clearest example sits just outside Washington DC, in an area so packed with server farms that people call it Data Center Alley. In one incident there, a transmission line fault, the kind of routine hiccup that grids deal with all the time, caused more than 3 gigawatts of data center load to disconnect within seconds. That is roughly 3 percent of the entire demand on the PJM grid, one of the largest power systems in North America, vanishing almost instantly.
The utility, Dominion Energy, later clarified that it did not cut power to anyone. The data centers detected a disturbance and their own backup systems kicked in automatically, all at once, like a room full of people flinching at the same loud noise. Grid analysts pointed out something important afterward. When one customer represents 3 gigawatts of automatic, synchronized behavior, that customer is no longer just a customer. It is effectively part of how the grid itself behaves.
A similar worry comes up when people talk about the blackout that hit Spain and Portugal in April 2025. That event started with a loss of about 2.2 gigawatts of power generation, and within 27 seconds the entire grid across both countries had collapsed. AI data centers were not the cause of that particular blackout. But grid engineers in Texas have pointed to it as a preview of what could happen if a large cluster of AI facilities all disconnected or reconnected at the same moment, the same way the Virginia data centers did, just on a bigger scale.
On the more hopeful side, some companies are tackling the problem head on. xAI's Colossus supercomputer in Memphis is a good example. This is the facility built to train the company's Grok AI models, and it runs on a 150 megawatt connection to the local grid. To handle the power swings from tens of thousands of GPUs, xAI installed 168 Tesla Megapack batteries on site.
Each one can store more than 3.9 megawatt hours of energy, acting like a giant shock absorber that soaks up spikes before they ever reach the public grid. The facility also has onsite gas turbines as extra backup, though those drew some criticism for running beyond their permitted limits before some units were scaled back. Whatever you think of the environmental tradeoffs, the batteries are a very literal, very physical answer to a very literal, very physical problem.
Why This Keeps Regulators Up at Night
Grid operators do not scare easily. They deal with weather, equipment failures, and demand swings every single day. But AI load transients hit a nerve because of their scale and their pattern of happening all at once rather than gradually.
In the United States, the organization responsible for keeping the power grid reliable, called NERC, has taken this seriously enough to issue what is known as a Level 3 alert. That is a rare and urgent warning. NERC said plainly that many utilities did not have proper processes in place to handle these new computing loads. It then gave utilities a checklist of homework, including things like testing facilities at full load and no load, and installing better monitoring equipment to catch these fast swings as they happen. The deadline for compliance is August 2026.
Part of what worries regulators is something called common mode failure. If dozens of data centers are all built with the same safety thresholds, they may all react to a small grid disturbance in exactly the same way at exactly the same time. Instead of many small, independent responses, the grid gets one enormous, synchronized response. That is a bit like a stadium full of people all standing up at once because one person spilled a drink. Individually harmless, collectively chaotic.
And the stakes are only rising. NERC's own long term outlook projects that summer peak electricity demand will climb 24 percent over the next decade, with data centers doing most of the pushing. More AI clusters means more of these synchronized power heartbeats spreading across more of the grid.
How Engineers Are Fighting Back
The good news is that smart people are already working on fixes, and some of the solutions are refreshingly clever.
Batteries are the most obvious answer, and they work well. Companies like FlexGen build battery systems specifically designed to sit between the data center and the grid, soaking up sudden spikes and filling in sudden dips. Some of these systems can smooth out 99 percent of the fast fluctuations before the grid ever notices them happened.
A more surprising fix comes from software rather than hardware. Oracle Cloud Infrastructure built a system with the friendly sounding name AET, short for Average Elapsed Time. Instead of adding more batteries, Oracle's engineers taught their systems to notice the split second gaps when GPUs are idle, waiting for their teammates to finish a calculation, and quietly fill those gaps with extra background work.
It is a bit like a chef who, instead of installing a bigger stove, teaches the kitchen staff to chop vegetables during the thirty seconds a pot is simmering. Nothing physically changes about the power supply. The workflow itself gets smoothed out instead.
Between smarter software, bigger batteries, and new grid rules requiring data centers to ride out disturbances instead of tripping offline, this is a solvable problem. It just requires treating a data center less like a giant office building and more like what it has actually become, a power plant sized customer with its own heartbeat.
The Takeaway
AI load transients are what happens when tens of thousands of computer chips decide, almost in unison, to either work as hard as they possibly can or take a very quick nap. That synchronized behavior creates electricity swings so fast and so large that power grids built for slower, gentler changes are struggling to keep up.
The examples are already piling up, from a 3 gigawatt disconnection outside Washington DC to battery warehouses in Memphis built specifically to absorb these shocks. Regulators are watching closely, engineers are building clever fixes, and the rest of us mostly just notice the effects when our electricity bills or our local grid reliability start making headlines.
So the next time someone tells you that AI is just software running in the cloud, you can tell them about the tea kettles. Somewhere, a warehouse full of GPUs just paused to compare notes, and a power grid somewhere just felt it.
Sources
- NESO: EURO 2020 and the TV ‘pick-up’ effect
- Meta AI (arXiv): The Llama 3 Herd of Models
- Oracle Cloud Infrastructure Blog: A Tiny GPU Heartbeat for Smoothing AI Power Spikes
- PJM Inside Lines: PJM, Dominion Review Large Load Transfer Event
- Utility Dive: Sudden data center load losses prompt NERC alert, recommendations
- POWER Magazine: NERC warns long-term grid reliability risks mounting from surging demand, lagging resources
- ENTSO-E: 28 April 2025 Iberian blackout, investigation and final report
- Bloomberg: Musk’s xAI to use Tesla batteries at Memphis supercomputer
- FlexGen: AI transient loads and multi-asset orchestration


