• PJM would apply the framework from 1 June 2027 to new sites with at least 50MW of cumulative peak demand
  • Data centres without qualifying capacity arrangements could use interim service but would face earlier curtailment during shortages

The fact

PJM Interconnection’s board has asked the grid operator to submit new rules for large electricity users, including data centres, to the Federal Energy Regulatory Commission. From 1 June 2027, projects that cannot be served without weakening regional reliability would need to secure enough generation, arrange another approved source of supply or use PJM’s Interim Resource Adequacy Service. Customers on the interim service could be curtailed earlier during capacity shortages. The rules would only take effect if FERC approves them.

PJM runs the wholesale electricity market and transmission system for 67 million people across parts of 13 US states and Washington, DC. It defines a large load as a site with at least 50MW of cumulative peak demand. PJM expects large-load demand to grow by about 70GW by 2038, while around 15GW of generation has retired since 2022. Its latest capacity auction still left the region 6,831MW short of its reliability requirement.

The assessment

If approved, PJM would make firm service a separate requirement from grid connection. A data centre could have the physical infrastructure needed to connect but still need to prove that enough generation or another qualifying supply arrangement supports its demand. Without that backing, the site could use the interim service but would face a greater risk of curtailment during regional shortages. Developers and utilities would therefore need to address capacity supply alongside connection and energisation plans.

The effect will depend on rules that remain unsettled, including what qualifies as adequate supply, who pays for additional capacity and how curtailed customers are compensated. New generation may also become available later than the campus it is intended to support. For BTW readers, the proposal would make firm power a separate project dependency: developers would need either to secure qualifying capacity before full operation or accept temporary limits on service.

What to watch

Watch PJM’s FERC filing for the supply-verification, curtailment, compensation and cost-allocation rules. The Large Load Registry should clarify how project demand and supply arrangements will be recorded. Early bilateral contracts and participation in the interim service will indicate whether developers secure capacity in advance or accept curtailment while waiting for supply.