NERC Sets Data Center Reliability Rules at 50 MW and 100 kV, a Threshold FERC Declined to Name

The North American Electric Reliability Corporation has drafted three reliability standards for data centers, and the drafts name the size at which the rules bite. They apply to a computational load site with a total connected load of 50 MW or more. That site must also draw power through equipment connected at 100 kV or above. The first formal comment period and its 10-day ballot closed on September 18, 2026. FERC ordered the standards on July 16, 2026 and set a filing deadline of December 31, 2026. FERC set no size threshold itself.

What Actually Changed

Three drafts carry the work. CLO-001-1 covers Computational Load Interconnection, Studies, and Modeling Data. CLO-002-1 covers Computational Load Operational Data and Communications. CLO-003-1 covers Computational Load Protection Coordination and Disturbance Monitoring.

They also create two entity types absent from the NERC glossary today. A Computational Load Owner owns and maintains a computational load site. A Computational Load Operator operates one. The drafts define that site as buildings or installations at one location. They must primarily hold information technology infrastructure, including artificial intelligence training and cryptocurrency mining. They must also connect to the bulk power system.

CLO-003-1 carries the measurement duties. It requires sequence of event recording for circuit breaker position. It also requires triggered fault recording on the high side of the main power transformer. That record must capture phase-to-neutral voltage on each phase. It must also capture each phase current with the residual or neutral current, plus real and reactive power on a three-phase basis. The draft sets a minimum recording rate of 64 samples per cycle. It sets a pre-trigger length of at least two cycles and a total record length of at least 2.0 seconds. Triggers must cover neutral overcurrent, AC phase overvoltage and undervoltage, and overfrequency and underfrequency. A fourth requirement adds continuous dynamic disturbance recording.

CLO-002-1 works differently. It puts the duty on grid operators to write down what they need. Transmission Operators, Balancing Authorities and Reliability Coordinators each must maintain a documented specification for the site data feeding their operating analyses. Each specification needs deadlines, accuracy criteria and a transfer method both sides agree on.

Why It Matters

Grid operators set their own numbers while NERC worked. The Public Utility Commission of Texas approved NOGRR282 in July, which reaches ERCOT data centers and crypto-mining sites of 75 MW or larger. CAISO proposed defining a large load as a single site with a peak load of 50 MW or greater. MISO drew its large-load line above 50 MW, then counted such a load as computational once it carries at least 25 MW of information technology demand. A continent-wide 50 MW floor sits underneath that spread rather than replacing it.

The second half of NERC’s clause deserves equal attention. Both tests apply together. A site clears the load test at 50 MW, but it stays outside all three standards unless its supplying equipment also sits at 100 kV or above. That leaves large sites fed at distribution voltage outside this round. The comment file closed on September 18 with the language intact.

What Did Not Change

FERC’s July 16 order set no size threshold, no registration category and no compliance obligation. It left all three to NERC. Revisions to the existing MOD, PRC, TOP/IRO and COM standard families stay out of this round, and NERC flagged them for a possible Phase II. On cost, the authorization request states plainly that impacts are unknown. It anticipates they are significant and that they vary by entity and region.

Enforcement Reality

Every requirement in CLO-003-1 carries a Violation Risk Factor of Lower and a Long-term Planning time horizon. That is the mildest pairing NERC assigns. The harder question is registration. These standards reach an operator only once that operator sits on the NERC registry as a Computational Load Owner or Operator. That registry change rides on a separate revision to NERC’s Rules of Procedure. The schedule leaves little slack. A 20-day comment period with a further ballot falls in October 2026. A five-day final ballot follows in November. Board adoption lands in December, the same month as the FERC deadline.

Critical Perspective

Read the enforcement weight before reading the requirements. Every duty in CLO-003-1 arrives with a Violation Risk Factor of Lower and a Long-term Planning horizon. That is the gentlest pairing NERC hands out. The recording obligations are real, but the penalty exposure behind them starts small.

The registry question matters more. None of this reaches a data center operator until that operator is registered as a Computational Load Owner or Operator. That change moves on a separate Rules of Procedure track. Board adoption in December produces a standard with nobody registered to apply it to if the registry work slips.

Then there is the price. The authorization request states that cost impacts are unknown, while anticipating that they are significant and that they vary by entity and region. Industry balloted requirements in September that NERC has not costed.

Sources

• NERC, CLO-002-1 Computational Load Operational Data and Communications, Draft 1
• NERC, CLO-003-1 Computational Load Protection Coordination and Disturbance Monitoring, Draft 1
• NERC, CLO-001-1 Computational Load Interconnection, Studies, and Modeling Data, Draft 1
• NERC, Standard Authorization Request: Reliability Standards to Address Computational Load Phase I
• POWER Magazine, FERC Orders Mandatory NERC Reliability Standards for Data Center and Other Computational Loads

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