1,500 Megawatts at Once

Summary

On 10 Jul 24 a fault on a 230 kV transmission line in the eastern half of the country set off six more faults, and about 1,500 megawatts of data center load came off the system at nearly the same moment. Frequency rose to 60.047 Hz against a nominal 60. When that much load disappears at once the generators are suddenly making more power than anybody is using, and the whole system speeds up.

Two years later there is a rule coming out of it. On 16 Jul 26 the Federal Energy Regulatory Commission (FERC), the federal agency that regulates the grid across state lines, ordered mandatory standards written for big computing loads by 31 Dec 26. Writing them falls to the North American Electric Reliability Corporation (NERC), which enforces the grid's reliability rules and can fine a utility for breaking them. Those rules have never reached the load itself before.

Findings

The order covers what FERC calls computational load, drawn wide enough to take in AI data centers along with cryptocurrency mines.

The part that matters most is who has to answer for it. FERC also told NERC to rewrite its registration criteria so the data centers themselves can be held to the standards directly. Until now that obligation has sat with the utilities and the generators. A further work plan is due 1 Mar 27.

NERC had already moved on its own. It issued a Level 3 alert, its most serious grade, directing utilities to take seven immediate actions after watching large loads cut themselves off and oscillations run through the system in seconds, leaving nobody room to respond in real time.

The states did not wait either. Texas Gov. Greg Abbott called for an audit of every data center waiting in line to connect to the Texas grid on 3 Aug 26. That line holds about 474 gigawatts of requests, more than five times the highest demand Texas has ever recorded, and Abbott put roughly 90 percent of it on data centers. The Electric Reliability Council of Texas (ERCOT), the nonprofit that runs that grid, delayed its first round of study and goes in front of the state utility commission on 20 Aug 26. New York paused new approvals in July for as long as a year.

How much of that line is real is its own question. Exelon told investors its high-confidence data center load fell 40 percent, down to 11 gigawatts, once it started making developers sign agreements that sort the real projects from the placeholders. Bloomberg's research arm figures the Texas pause alone puts about a fifth of the national pipeline at risk of delay.

Impact

Generators have been held to ride-through requirements for decades. They have to stay connected through a dip instead of tripping off and making the problem worse. Load never carried that requirement, because load was assumed to be diverse. Thousands of customers doing unrelated things do not all react the same way at the same instant.

A building full of identical equipment carrying identical protective settings is not diverse. That is why 1,500 megawatts went at once.

For anybody who works in these buildings, the change lands on the electrical side. If the facility itself gets registered, the obligation follows it. Protective relay settings and ride-through capability stop being a commissioning note and start being a compliance record somebody has to produce on demand.

There is a bill underneath all of it. Everybody on the system has been paying for reliability while the load that put it at risk got treated as an ordinary customer.

Recommendations

If you work data center electrical, go find out what the ride-through specification actually is on the UPS and on the protective relaying, and whether anybody ever wrote it down. That document is about to be worth something.

Watch two dates. NERC has to file by 31 Dec 26. Texas goes in front of its utility commission on 20 Aug 26.