PJM Large Loads: What FERC’s October 9 Order Kept and Rejected

The short version

On August 13, 2026, PJM asked FERC to approve a package for connecting new data centers and other large loads while it faces a capacity shortfall. On October 9, FERC split it. It accepted a tariff definition of “Large Load” and a Large Load Registry, effective October 12, 2026. It rejected the remainder: the Interim Resource Adequacy Service (IRAS), the “Bring Your Own New Capacity” (BYONC) rules, and the proposal to exclude certain new large load from the capacity auction demand curve starting with delivery year 2029/2030 (FERC order, Docket ER26-3515-000, Oct. 9, 2026, paras. 1–2, 13).

This is a wholesale-tariff order about how PJM defines and tracks large loads and who is curtailed in a shortage. It does not change how a generation project enters the interconnection queue, and it does not change any utility’s retail service rules.

What FERC accepted

The definition. PJM’s accepted definition has these elements (order, para. 17):

• A cumulative peak of 50 MW or more;
• at a single electrical site behind one or more points of interconnection within a one-mile radius, so a developer cannot avoid the definition by building several sub-50 MW buildings close together;
• including co-located loads and loads with behind-the-meter generation; and
• with no voltage threshold.

FERC rejected protests that 50 MW is arbitrary, noting that any cutoff excludes loads just below it (para. 27), and rejected arguments to limit the definition to data centers (para. 28). PJM said it will describe in its Manuals how the one-mile distance and “single electrical site” are measured; FERC treated that as an implementation detail (para. 30). That manual language is the part land teams will want to read when it appears.

The registry. The Large Load Registry is a PJM database of Large Load information, including location, ramp schedule and capacity supply, which PJM says will support load forecasting and transmission planning and be shared with state commissions and transmission owners under confidentiality rules (order, paras. 13, 34). FERC required PJM to submit a compliance filing within 30 days of the October 9 order (para. 2). Who must report, and how much detail, is left to PJM manuals and the compliance filing; I could not confirm those details from the order alone.

What FERC rejected, and why

IRAS would have let a new large load connect without bringing new capacity, on the condition that it could be curtailed, or switched to on-site backup, before other customers when PJM lacked resources in real-time operations. Load serving entities would instead have been required to designate new capacity at least equal to the new large load’s peak to avoid IRAS (order, paras. 1, 12).

FERC said it recognized the shortfall but found that IRAS and BYONC are “either outside of the Commission’s authority or have not been sufficiently demonstrated to be just and reasonable” (para. 14). Protesters argued, among other things, that the curtailment and compensation terms reach into state authority over retail service and rates (paras. 56–61, 73). FERC also treated the remaining pieces as an integrated package that could not be accepted separately (para. 15). Because the VRR-curve exclusion depended on that package, it fell with it.

FERC offered guidance if PJM refiles, including that PJM should address existing commercial arrangements with generators, and that the tariff as written would have treated a 49 MW existing load adding 1 MW as a 50 MW new large load for its whole 50 MW (para. 110). It is guidance, not a directive; PJM has no obligation to refile.

The backstop procurement is a separate track

A second order is easy to confuse with this one. On September 29, FERC accepted PJM’s Reliability Backstop Procurement (RBP), a one-time procurement of new capacity, but suspended it for five months, effective February 28, 2027, subject to refund, and set a paper hearing (FERC order, Dockets ER26-3380-000 and EL26-108-000, Sept. 29, 2026). PJM’s stated RBP target started from the 6,831 MW shortfall in the 2028/2029 Base Residual Auction, before downward adjustments (same order). FERC urged PJM to file a new section 205 proposal quickly, which could make the paper hearing unnecessary.

PJM told FERC it plans to file a new section 205 proposal on the backstop procurement, covering cost allocation, Transmission Owner exit responsibilities and load-serving-entity collateral, by October 29, 2026 (PJM filing letter, Docket EL26-108-000, Oct. 12, 2026). PJM is consulting its Members Committee on that filing at a special meeting on October 22 (PJM agenda). That meeting is a consultation, not a vote. As of October 22, I had not seen the filing itself or any report of the meeting, so its contents are not covered here.

What this means for developers and land teams

• Being a 50 MW site now has a tariff meaning in PJM. If you are assembling parcels for a campus, the one-mile aggregation rule means splitting a project into sub-50 MW phases on adjacent parcels is unlikely to keep it outside the definition. Check the Manual language when it is published.
• The curtail-first bargain is off the table for now. A path to connect sooner in exchange for being curtailed first is not in the tariff. Whether PJM, states or utilities propose a version is open. Do not underwrite a timeline on a program that FERC rejected.
• The capacity shortfall is unchanged. PJM’s filing says it will be short of capacity beginning in the 2027/2028 delivery year, driven by data center growth (order, para. 3). Expect continued pressure on how large loads are charged for new capacity.
• For generation developers, the same shortage is why new capacity is in demand. Site control and queue milestones are unaffected by this order; see our guides to PJM site control requirements and the data center versus generation queue dynamics.

What I could not verify

• What PJM actually files on or before October 29, and what was said at the October 22 consultation. Both dates come from PJM documents; the outcomes were not yet available.
• The exact scope of the compliance filing and the content of the forthcoming PJM Manual revisions.
• Whether PJM will seek rehearing or refile an IRAS-like proposal, and any state-level actions. None was confirmed as of October 22, 2026.
• Claims in press coverage about the amount of data center load currently connected to PJM; I did not check these against a PJM document and do not use them here.

Frequently asked questions

How does PJM now define a Large Load?

Under the tariff revisions FERC accepted on October 9, 2026 (Docket ER26-3515-000), a Large Load is end-use customer load with a cumulative peak of at least 50 MW at a single electrical site behind one or more points of interconnection within a one-mile radius. It includes co-located loads and loads with behind-the-meter generation and has no voltage threshold.

Did FERC approve PJM's curtail-first plan for new data centers?

No. FERC rejected the Interim Resource Adequacy Service (IRAS), the Bring Your Own New Capacity rules, and the exclusion of eligible new large load from the capacity auction demand curve. It found IRAS and BYONC either outside its authority or not shown to be just and reasonable, and it offered guidance should PJM refile.

What is the PJM Large Load Registry?

A PJM-maintained database of information on Large Loads, including location, ramp schedule and capacity supply. FERC accepted it effective October 12, 2026 and required a compliance filing within 30 days of the October 9 order.

Sources

• FERC, Order Accepting Tariff Revisions in Part and Rejecting in Part, PJM Interconnection, L.L.C., Docket ER26-3515-000, 197 FERC ¶ 61,019, issued October 9, 2026 (PJM-hosted copy). Source for definition, registry, effective date, 30-day compliance, rejected elements, December 2026 auction timing and the August 13, 2026 filing date.
• FERC, Order Accepting Reliability Backstop Procurement and Establishing Further Procedures, Dockets ER26-3380-000 and EL26-108-000, 196 FERC ¶ 61,245, issued September 29, 2026 (PJM-hosted copy). Source for suspension to February 28, 2027, paper hearing and 6,831 MW starting target.
• Utility Dive, “DOE presses PJM on ratepayer protections from large load costs,” October 8, 2026. Background on DOE's request that PJM file by October 29 (secondary).
• PJM, filing letter in Docket EL26-108-000, October 12, 2026 and Special Members Committee agenda, October 22, 2026. Source for the October 29 filing target and the October 22 consultation (primary).
• PJM Inside Lines, proposed large-load framework, August 13, 2026. Background on IRAS as filed.

Related articles

• PJM Site Control Requirements in 2026: The Complete Developer Guide — Cycle 1 thresholds and Manual 14H attestation.
• Data Centers vs. Renewables: How AI Load Growth Is Reshaping the Interconnection Queue — Background on load growth and queue competition.
• PJM market hub — Queue rules and resources for PJM.