On 9 October 2026 the Federal Energy Regulatory Commission issued an order in Docket ER26-3515-000 (197 FERC ¶ 61,019) on PJM Interconnection’s plan for connecting data centres and other very large electricity users. PJM runs the grid and wholesale power markets for 13 states and the District of Columbia. FERC accepted two pieces of the 13 August filing and rejected the rest.
Why PJM filed
As FERC’s order summarises it, PJM says that beginning in the 2027/2028 delivery year it will be short of the capacity needed to meet its regional reliability requirement, “particularly due to data center load growth and the pace of data center interconnection.” PJM wanted its new service in place by 1 June 2027.
What FERC accepted
- A ‘Large Load’ definition: a cumulative peak load of at least 50 MW at a single electrical site. FERC called the threshold a just and reasonable balance.
- A Large Load Registry, effective 12 October 2026. The utilities serving these loads must report information about them to PJM so it can forecast and plan. The data goes to state commissions, transmission owners, distributors, the market monitor and FERC under existing confidentiality rules. PJM will publish only aggregate figures. FERC rejected protests from state consumer advocates who wanted direct access.
PJM must make a compliance filing within 30 days of the order, stripping out the rejected language.
What FERC rejected
- Interim Resource Adequacy Service (IRAS). New large loads whose utility did not bring new capacity equal to their peak would have been curtailed when supply ran short. FERC found that the plan “appear[s] to present an impermissible intrusion on retail rate regulation”: it places obligations directly on new large loads, which are mostly retail customers; it dictates which retail customers get curtailed; and its compensation framework “appears to establish a retail rate.” Under the Federal Power Act, retail sales are for the states.
- Bring Your Own New Capacity (BYONC) and the related plan to exclude eligible new large loads from PJM’s capacity demand curve from 2029/2030. FERC said PJM had not justified locking in the accreditation value of capacity a data centre brings, which could leave the region buying too little or too much.
FERC also flagged problems PJM would need to fix if it refiles: curtailing firm load at an early emergency stage appears to conflict with mandatory NERC Reliability Standard EOP-011-4, which allows firm load to be cut only at the most severe stage (EEA3); and the plan would still have charged utilities for capacity PJM was not buying for those loads.
“PJM’s proposed construct appears to regulate the terms and conditions of a retail customer’s service in ways that are beyond the Commission’s authority.” — FERC order, Docket ER26-3515-000, 9 October 2026
Who argued what
The order records that Pennsylvania Governor Josh Shapiro backed IRAS as a way to keep the costs of data-centre growth off other customers. Constellation, the Data Center Coalition, Google, FirstEnergy and Vistra argued it unlawfully targeted a class of retail customers. Commissioner David Rosner concurred separately, saying that if PJM refiles it must justify mandatory curtailment.
What this piece refuses
Do not write that FERC “blocked data centres” or “approved cutting power to data centres.” It did neither: it rejected a specific tariff design and accepted a definition and a registry. We have not reported analysts’ forecasts of what this means for capacity prices or power bills; those are projections, not findings.
Bottom line
Verified from FERC’s order of 9 October 2026 (197 FERC ¶ 61,019): PJM gets a 50 MW large-load definition and registry, effective 12 October; its plan to curtail new data centres first, and its bring-your-own-capacity rules, were rejected as reaching into state-regulated retail service. Compliance filing due within 30 days.
