FERC Approved PJM's Data Center Registry and Rejected Its Curtailment Plan

The Federal Energy Regulatory Commission approved PJM Interconnection's registry for data centers and other large electricity users on October 9 and rejected the service that would have let those loads connect ahead of new generating capacity. The order in docket ER26-3515 severed two pieces of a package PJM filed on August 13 and threw out the rest, finding the remaining elements either outside the Commission's authority or not shown to be just and reasonable.

PJM operates the grid for 13 states and the District of Columbia and projects 32 gigawatts of load growth between 2024 and 2030, 30 of it from data centers. It had asked for an October 12 effective date so it could adjust capacity auction parameters before the 2029/2030 Base Residual Auction runs in December. The accepted definition sets a Large Load at a cumulative peak of 50 megawatts or more at a single site, or at affiliated sites within a one-mile radius. FERC called that definition just and reasonable and refused requests to narrow it to data centers alone, finding that manufacturing plants of the same size affect the grid the same way.

The registry that survived is a reporting obligation. Each qualifying load files its location, expected in-service dates, projected power consumption, capacity supply arrangements and backup generation capability, and PJM uses the database to forecast demand, study transmission service and share it with authorized agencies. What FERC struck was the Interim Resource Adequacy Service, which would have connected new large loads entering service after June 1, 2027 without matching new capacity in exchange for being curtailed first in a shortfall. The Bring Your Own New Capacity rules, the capacity designation requirement for load-serving entities and the plan to pull eligible new loads off the variable resource requirement curve went with it, rejected as inextricably linked.

New large load in PJM therefore connects under the framework that already exists, and the capacity question stays with the project. A campus that wants to energize ahead of new supply has no approved path to do it on curtailment terms, which keeps onsite generation and the medium-voltage scope around it in the base design: paralleling switchgear, transfer equipment, feeders from the yard to the gear, and the protection and controls that tie them together. The registry's backup generation field puts that capacity on the record.

FERC sent the curtailment question to state regulators, saying states have a crucial role to play in deciding which customers get cut first. Commissioner David Rosner wrote in a concurrence that homes, hospitals and schools should never be curtailed before data centers, and asked state commissions to set the order. The next round of rulemaking lands in 13 state capitals, and the hiring tied to this load tracks the generation and substation scope more than the data hall: medium-voltage cable and termination work, switchgear installation, acceptance testing, generator paralleling and the commissioning hours that close out each phase. Crews on those phases work to the license the project's state issues, not to PJM's footprint.

PJM said it is reviewing the order, and FERC laid out how a revised filing could come back. The registry stands; the rest returns to PJM, and the curtailment question to the states.