Data centers and computational loads
NERC has written the rules for data centers. The clock is running.
On October 26, 2026 the NERC Board adopted CLO-001-1, CLO-002-1 and CLO-003-1, the first reliability standards for computational loads of 50 MW and up at 100 kV or above. Registration is expected to begin in 2027. Getting a site through them requires a compliance program. GridStrong takes your site through registration, every study and every standard, and keeps the record the operator and the auditor will ask for.
Why this is different
A load that behaves like a power plant, at a scale transmission planning has never seen.
Every load source is its own dynamic model
The load sources inside a computational data center each present a complex, variable load model. Combined, they are a new problem for the power systems modeling industry, and the operators' modeling requirements are still being written.
Voltage and frequency at gigawatt scale
Variable and dynamic load profiles present stability challenges of a size never encountered in AC stability analysis. A single site can now move the system the way a large generator does.
Ride-through is now the load's obligation too
A plant that drops off during a fault becomes a grid event. Operators are writing ride-through and connection requirements for large loads that mirror what generators already carry.
The record
Nothing failed. Everything did what it was set to do.
Three times in two years, large blocks of computational load have left the grid during faults the system cleared correctly. In 2024 none of the 1,500 MW was disconnected by utility equipment. It went off on the customers' own protection settings and stayed off until someone reconnected it by hand.
| Event | What happened | Why it matters |
|---|---|---|
| July 10, 2024, Northern Virginia | A 230 kV fault. About 1,500 MW of data center load dropped at about 60 load points across 25 to 30 substations. | NERC's review found none of it was disconnected by utility equipment. Customer-side protection and disturbance counters did it, per customer settings. |
| July 22, 2026, Northern Virginia | A 230 kV line failed at 7:56 am. PJM load fell from 99,984 to 96,205 MW, about 3,800 MW, in two waves. | The largest sudden load transfer in PJM's history. The fault cleared correctly with no misoperations. Area control recovered in nine minutes. |
| ERCOT, 2023 to 2025 | 26 large electronic load ride-through events during normally cleared faults, as of late 2025, and 28 trips of 100 MW or more since 2023. | Each one was a facility protecting itself. ERCOT's 2025 study showed about 1,500 MW leaving on one West Texas fault; its May 2026 assessment flags load groups above 3,200 MW. |
Sources: NERC incident review, Considering Simultaneous Voltage-Sensitive Load Reductions (January 2025) and NERC presentations; PJM Operating Committee preliminary findings, August 6, 2026; ERCOT Board, December 2025, and Large Load Workshop, June 2025.
The load
Why the generator playbook does not transfer cleanly.
Inverter-based generation took the industry ten years to get from its first large event to its first ride-through standard. The load side is moving in about two and a half. The hard part is the same: the equipment has controls with an opinion.
Motors and heaters: slow, well understood, represented in aggregate by composite load models built around them.
Load follows voltage and frequency. It does not have controls with an opinion.
One facility, one owner, one technology. Positive-sequence phasor tools were enough.
A multi-vendor microgrid: UPS, rectifiers, batteries, STATCOMs, drive-driven cooling and backup generation, each with its own protection.
Power-factor regulated rather than voltage regulated, with training cycles that swing tens of MW in seconds.
Control dynamics above 5 Hz, beyond what phasor-domain tools can see. EMT is becoming routine for loads, as it did for inverter-based resources.
Draws on NERC's Reliability Guideline, Risk Mitigation for Emerging Large Loads (May 2026), and the Large Loads Task Force white paper, Characteristics and Risks of Emerging Large Loads (July 2025).
The rules
Two regulatory tracks are converging on the same facility.
One track governs how the load behaves on the grid. The other governs how it is served and what it pays. The same facility must satisfy both. Most developers are tracking one.
How the load behaves
NERC Level 3 Alert (May 4, 2026): seven essential actions covering model data, studies, qualified change, commissioning, protection, fault recording and communications. Responses were due August 3.
NERC Project 2026-02: CLO-001 (interconnection, studies, models), CLO-002 (operational data), CLO-003 (protection and disturbance monitoring), at 50 MW connected at 100 kV or above. The initial ballot passed in September and the final ballot on October 14; the NERC Board of Trustees adopted the standards on October 26, 2026, and NERC files them with FERC by December 31, 2026 under docket RD26-7. They are not in force until FERC approves them. Ride-through is Phase II, with a work plan due March 1, 2027.
Regional ride-through, ramp and PMU rules: ERCOT's are in effect, MISO's are filed, PJM's are proposed.
How the load is served
FERC show-cause orders to all six RTOs and ISOs (June 18, 2026, dockets EL26-67 to EL26-72): study process, cost transparency, co-location, flexible-load service and electrically proximate load. Answers are due November 16 and 20.
RM26-4, the DOE-directed large-load rulemaking, stays open. A nationwide rule reaching non-RTO regions is still possible.
Non-firm and conditional service products: SPP's Conditional High Impact Large Load Service (CHILLS) accepted, MISO's FLITS non-firm service in design, CAISO's Flexible Interim Load Interconnection (FILI) approved by its Board, ISO-NE interim and non-firm contract demand service, PJM's interim resource adequacy service pending.
Region by region
Where each region stands.
Checked against the public filings and stakeholder materials on October 8, 2026; the CAISO row was rechecked on October 29. Several rows are proposals, not approved tariff.
| Region | Reliability requirements | Flexible or non-firm service | Next date |
|---|---|---|---|
| ERCOT | NOGRR 282 ride-through in effect since August 1 (75 MW, half or more power-electronic). PGRR 144 model quality at the PUCT. Draft limit of 10 MW variation per 5 seconds. | SB 6 curtailment authority. Batch Zero: 362 loads conditionally classified, about 190 GW. | Variation NOGRR, fall 2026; Batch Zero allocations, spring 2027 |
| MISO | ER26-3650 filed August 28: data, models, PMU, ramp and ride-through at 50 MW. | FLITS non-firm service in design. Zero-injection GIA filed August 18. LARS paired-study queue filed October 2. | November 16 answer; December 2 and December 4 requested effective dates |
| PJM | Ride-through proposed September 8, revised October 6 (50 MW with 25 MW power-electronic; no voltage test). Ramp design in 2027. | Interim resource adequacy service (ER26-3515, pending): loads without new capacity are cut first, from June 1, 2027. | FERC filing November 16 |
| SPP | High Impact Large Load study process, accepted January 14, 2026. | CHILLS accepted June 5, effective July 1: up to seven years of conditional service. | Show-cause in abeyance to November 20 |
| CAISO | 50 MW definition, no voltage test. | FILI (interim) approved by the Board on October 28; FLIP (permanent) deferred. | Section 205 filing November 16 |
| ISO-NE | 50 MW above 60 kV. 90-day studies, EMT where needed. | Bring your own new capacity; firm, interim and non-firm service. | Section 205 filing November 16 |
Scroll sideways on a phone to see the whole table.
NYISO is in abeyance with a firm and non-firm split under design. In Canada, AESO runs a staged interim process and IESO recognizes large step loads in planning, both as of December 2025. Texas sits outside FERC's show-cause set.
Ride-through
Ride-through rules are converging on the generator template.
PRC-024 became PRC-029 for inverter-based generators. The load curves share that shape: a continuous band, timed bands either side, a deep-sag floor, a recovery clock and a ban on sag-counting transfer schemes. NERC's Large Loads Working Group is drafting a national envelope separately.
| Parameter | ERCOT NOGRR 282 (in effect) | MISO ER26-3650 (filed; values per the June draft) | PJM proposal (October 2026) |
|---|---|---|---|
| Applies to | Large loads of 75 MW or more, half or more power-electronic | Computational part of large loads of 50 MW or more | Large computational loads of 50 MW or more with 25 MW or more power-electronic |
| Continuous range | 0.90 to 1.10 pu and 58.8 to 61.2 Hz | 0.90 to 1.20 pu with no power reduction; 58.8 to 61.2 Hz | 0.90 to 1.10 pu and 58.8 to 61.2 Hz |
| Frequency bands | 299 s at 57.5 to 58.8 and 61.2 to 63.0 Hz | 57.0 to 58.8 and 61.2 to 61.8 Hz; rate of change of frequency to 5 Hz/s | 299 s at 57.0 to 58.8 and 61.2 to 61.8 Hz |
| Deep voltage sag | 0.25 s at 0.35 to 0.50 pu; 0.15 s below 0.35; cooling may trip below 0.35 | Draft curve allows tripping below 0.25 pu | Reduce as needed below 0.50 pu; cooling may trip below 0.35 |
| Recovery | 90% of pre-disturbance consumption within 2 s of voltage above 0.9 pu | Back to 90% within 1 s | Back to 90% within 2 s |
| Protection | No unfiltered instantaneous trips or counter schemes; overcurrent capped at 150% for 0.5 s | Three events in 10 s; 1.1 pu volts per hertz for 45 s | No counter schemes; overcurrent capped at 150% |
Scroll sideways on a phone to see the whole table.
Ramp limits follow the same pattern: ERCOT drafts 10 MW per 5 seconds, MISO sets limits in its business practices manual, PJM sets a ramp rate in 2027. MISO's filed tariff puts the ride-through criteria in its manual; the values shown are its June draft.
How it works
The full grid-code program a generator runs, now required of the load.
The same record, models, requirements and procedures that run a generation fleet run a data center: from the interconnection request through energization and into the operating program.
Plant profile
Load-side equipment, UPS and power-electronics topology, capability curves and settings populated from the developer's source files into one profile, versioned and permissioned.
Interconnection studies
Application models, cluster and facility studies, and the modification requests that follow a design change, prepared and filed in the operator's system on the developer's behalf.
Ride-through evaluation
The operator's large-load ride-through suite encoded as test cases and run against the load model, with automated pass or fail against the operator's rulebook in force.
Requirements tracking
As standards for large load take shape across NERC, ERCOT and the ISOs, each new requirement is indexed, mapped to the site and tracked to its deadline.
In practice
ERCOT's large-load ride-through suite, built into the harness.
When ERCOT issued its ride-through requirements for large loads, GridStrong encoded the suite as test cases so a data-center plant model runs against it the same way a generation model runs against a generator suite. That includes the connection-counter test, which requires the site to ride through six voltage sags inside ninety seconds, each sag stepped with its own hold points so the playback matches the requirement exactly.
- Every case runs in a fresh, isolated virtual machine and is destroyed when it finishes
- Results are on the developer's Dashboard as they complete, with the traces behind every verdict
- The operator receives the study in its own format, from the same record
Your obligations
What a developer delivers, and when.
Whatever the region, the floor is the same: a validated model, ride-through to equipment capability, ramp limits, PMU visibility, a commissioning check and a flexibility story. Of the ten facility characteristics an interconnection study needs, from UPS transfer thresholds to a validated EMT model, only the point-of-interconnection protection settings are reliably available from today's processes. The rest sit in manufacturer documents, facility design files and operator-held workload data.
The data package
Size and power factor by season and build-out stage; short-circuit contribution including backup generation; load composition, UPS settings and the IT versus non-IT split; maximum ramp up and down; protective-device settings and reconnection behaviour; on-site generation and storage; harmonics against IEEE 519; the telemetry list. FAC-002 and MOD-032 already bind the transmission planner to ask.
The verified model
A verified as-built model where the operator runs model quality tests (ERCOT has proposed them for large computational loads at the stability study, each change and energization). Full-load and no-load tests, voltage tests at plus or minus 10 percent, relay settings on file and a commissioning record, following the pattern NERC's Level 3 alert set.
The operating program
Ride-through to equipment capability with no sag counters; ramp limits; PMU or fault-recorder data on request; telemetry and forecasts; every material change studied before it is built. In ERCOT an event brings a root-cause analysis within 90 days, a corrective plan within 90 and implementation within 180.
Registration and standards
Register as a computational load owner or operator at 50 MW connected at 100 kV or above, once FERC approves the registry criteria NERC files by December 31, 2026. Then CLO-001 (interconnection, studies, models), CLO-002 (operational data) and CLO-003 (protection and disturbance monitoring). Ride-through follows in Phase II.
Key dates
| Date | What happens |
|---|---|
| October and November 2026 | Project 2026-02 final ballot passed October 14 and the NERC Board adopted the standards on October 26; the FERC filing follows by December 31. ERCOT files its load-variation NOGRR. |
| November 16, 2026 | Show-cause answers due from PJM (with its ride-through tariff language), MISO, CAISO, ISO-NE and NYISO, most as Section 205 filings. SPP follows November 20. |
| December 2, 2026 | MISO's requested effective date for LARS, its paired load-and-generation study queue; the first 120-day study period opens in the first quarter of 2027. |
| December 4, 2026 | MISO's requested effective date for ER26-3650, its large-load data, model, PMU, ramp and ride-through rules. |
| December 31, 2026 | NERC files CLO-001, CLO-002, CLO-003 and the registry criteria with FERC by December 31, 2026, following the Board's October 26 adoption. |
| March 1, 2027 | NERC's Phase II work plan, including load ride-through, is due at FERC. |
| June 1, 2027 | PJM interim resource adequacy service exposure begins for loads without new capacity, if FERC accepts it. |
| January 1, 2028 | ERCOT's stricter tier: loads qualifying after this date must hold consumption proportional to voltage between 0.8 and 0.5 pu. |
FERC's RM26-4 docket remains open. Dates as filed or proposed on October 8, 2026; the Project 2026-02 ballot row was rechecked on October 29.
Who it is for
Data-center developers
Getting through the queue, meeting the operator's modeling and ride-through requirements, and keeping the interconnection agreement's obligations in one place after energization.
Hyperscalers and colocation operators
A single record across a portfolio of sites in different markets, so the same study is not rebuilt from scratch for every operator and every requirement change.
Utilities and system operators
A consistent, reviewable load model and study package from every applicant, tested against the operator's own rulebook and delivered to its systems.
See it on your site.
A working session with a GridStrong engineer on your load model, your operator's requirements and your queue position.