FERC rejects PJM's large-load curtailment plan, keeps the load registry

PJM's rules for a Large Load Registry, which require load-serving entities to report data centers and other loads of 50 MW or more at one site, take effect October 12, 2026; PJM's plan to cut new ones off early in a shortage did not survive. The Federal Energy Regulatory Commission on October 9 accepted PJM Interconnection's definition of a Large Load, end-use customer load with a cumulative peak of 50 MW or more at a single electrical site, and a Large Load Registry to track those loads, and rejected the rest of PJM's August 13 filing in docket ER26-3515 as one package. That package held the Interim Resource Adequacy Service (IRAS), under which new large loads could be curtailed in shortages unless offset by new capacity from PJM's backstop procurement or a Bring Your Own New Capacity (BYONC) arrangement, and the BYONC rules themselves.

What changes for large loads

The definition counts affiliated facilities within a one-mile radius as a single site, so an owner cannot stay under the threshold by building several data centers of under 50 MW each close together. The definition covers every kind of large load, data center or otherwise: FERC turned down FirstEnergy's and other parties' requests to leave out manufacturing, finding that protesters did not appear to argue that other large loads use less energy or affect the grid differently.

Load-serving entities will report each large load they serve to PJM, including its location, peak load and ramp schedule, and backup generation. State commissions, transmission owners, electric distributors, load-serving entities, the Market Monitor, FERC and other entities can see the data under PJM's existing confidentiality rules; the public gets aggregates on PJM's website, and state consumer advocates, who asked for access, remain outside. FERC found the registry valuable "separate and apart from" IRAS and agreed that PJM needs visibility into all large loads, existing ones included; industrial customers "will only be included in the Large Load Registry for informational purposes."

PJM has 30 days from the order to file tariff language that keeps the definition of Large Load and the registry but drops the definition of New Large Load, which FERC rejected without prejudice, along with the IRAS and BYONC language.

The rest is gone for now: the requirement that load-serving entities with new large loads designate new capacity at least equal to each load's peak, the curtailment service, and the exclusion of uncovered new large load from the capacity auction's demand curve from the 2029/2030 delivery year. PJM had asked for the October 12 effective date for the whole filing so it could change the demand-curve parameters for the 2029/2030 Base Residual Auction, set to run in December 2026.

Why FERC said no

The curtailment plan foundered on the gap between what PJM described and what it filed. FERC found that "certain aspects of PJM's proposal appear to present an impermissible intrusion on retail rate regulation." PJM's transmittal letter said it would only tell electric distributors how many megawatts to shed and leave the choice of customers to the states. The tariff it filed, FERC wrote, "appears to place obligations directly on the Eligible New Large Loads and requires Electric Distributors to curtail the Eligible New Large Loads," and its compensation, which FERC read as paid to those loads and funded by other retail customers, "appears to impermissibly set a retail rate." The proposal in the letter "may be within the Commission's jurisdiction," the order says. The tariff as filed did not appear to be.

IRAS would have cut firm load at EEA1, early in the emergency process, while Reliability Standard EOP-011-4 permits involuntary curtailment of firm load only after the reliability coordinator initiates an EEA3; FERC said the proposal appears to ignore the standard's plain language, a concern for any refiling. It also found that PJM had not shown how a customer's size or vintage matters to resource adequacy, when PJM's capacity market has historically bought capacity for all network load alike, and that locking a BYONC resource's capacity accreditation for the life of its arrangement was not sufficiently justified. FERC suggested that a non-firm transmission service like the voluntary one it raised in its PJM large-load show-cause proceeding "might be considered" for some of IRAS's aims, while noting that IRAS, unlike that service, was not voluntary.

Commissioner David Rosner concurred, writing that data centers not serving critical functions should be shut off before ordinary customers in an emergency ("homes, hospitals, and schools should never be curtailed before data centers"), but only after voluntary demand response is exhausted. PJM's filing, he wrote, "flips this paradigm" by proposing to force IRAS load off the system before demand response, the customers paid to volunteer.

The outcome is the one Google and Constellation asked for in their answers, the order notes: reject everything but the registry. Constellation had called its 890 MW nuclear uprate deal with Google on October 6 "a direct response" to PJM's bring-your-own-power proposal. The deal has now outlived the proposal it answered, at least this version of it.

The shortfall stays

None of this adds a megawatt. PJM's filing says the 2028/2029 auction cleared 6,831.3 MW short of the regional reliability requirement at the $325/MW-day price cap, the second straight year short. FERC's order acknowledges "the imminent capacity shortfall in PJM." The separate backstop procurement for up to 6,831 MW, one of the two ways to escape IRAS, is suspended to February 28, 2027.

The registry rules' effective date is also the first day of PJM's first Capacity Advisory, a new emergency procedure for an approaching capacity shortfall, issued October 9 for October 12 and 13. PJM blames warm fall weather and outages for maintenance and construction: it forecasts peaks of about 102,000 MW and 104,000 MW on those days against about 70,000 MW of scheduled generation outages. It says it is now seeing capacity issues in milder weather and expects them to increase "as demand growth outpaces the addition of new power resources."

Outlook

FERC set no date for a refiling, and the one deadline it set is the 30-day compliance filing. A voluntary version could surface in PJM's response to the large-load show-cause proceeding, where PJM told FERC it intends section 205 filings by early to mid-November that would include new transmission services for flexible large loads, per FERC's August 14 abeyance order, since FERC's show-cause order there already asked PJM whether its tariff remains just and reasonable without a non-firm service for flexible large loads. The order also hands part of the question to the states, which it says have a crucial role "by designating which retail customers must be curtailed when the system is stressed."