PJM Interconnection, the operator of the largest U.S. electrical grid, has announced it will temporarily cut power to data centers and other large electricity users during shortages to prevent broader blackouts. The curtailment program takes effect in June 2027 and applies to data centers drawing 50 megawatts or more — roughly the scale of a large hyperscale facility TechCrunch.

PJM's grid territory spans from Virginia to Illinois and serves 67 million customers. Wholesale electricity prices on the grid nearly doubled over the past year, and the operator is running another capacity auction — a competitive process where power generators bid to supply electricity for a future period — after a prior one fell short TechCrunch. Customers whose power is cut under the program will receive financial compensation, with advance notice ranging from 30 minutes to a few days.

The announcement formalizes authority PJM has been building toward for months. In May 2026, PJM received emergency federal approval to curtail power to data centers as a last resort before instituting rolling blackouts Utility Dive. That emergency authority specifically targets data centers equipped with backup generation capability. PJM wanted data centers to run on their own backup power during a late June 2026 heat wave that threatened record electricity demand across its territory, but needed federal approval to compel them to do so Maryland Matters.

PJM's own forecasting documents trace the pressure in detail. The 2026 Load Forecast Report documents data center load growth across multiple utility zones, including AEP, ATSI, APS, BGE, COMED, Dayton, DQE, JCPL, METED, and PECO PJM Load Forecast Report. The utility-level projections are striking in their specificity. PSE&G projected data center demand in its territory reaching 3,084 MW by summer 2031 and 3,461 MW by summer 2046 PSE&G documentation. NOVEC, the Northern Virginia Electric Cooperative, requested a forecast adjustment to reflect continued data center expansion in its service territory NOVEC documentation. AES Ohio submitted a large load forecast adjustment indicating that data center loads in the Dayton zone are expected to exhibit large, continuous growth AES Ohio documentation.

A May 2026 PJM special report, "Powering Reliability Through Market Design," goes further than emergency curtailment. It describes demand-side systems capable of reducing power consumption by 10%, 20%, or 30% in seconds through coordinated control of workload scheduling flexibility PJM Special Report. That language points toward a future where data center workloads are not merely interruptible but actively orchestrable as a grid resource. PJM's 2024 Regional Transmission Expansion Plan report had already identified data center proliferation as a primary driver of load growth PJM RTEP Report, and the operator's blog reinforced the point in January 2026, citing data center growth as a key factor in its 20-year long-term load forecast PJM Inside Lines.

The 50-megawatt threshold is a deliberate design choice. It captures the hyperscale facilities that dominate Northern Virginia's Data Center Alley and similar clusters in Ohio and Illinois, while leaving smaller enterprise and colocation sites outside the curtailment regime. The compensation mechanism and advance-notice window distinguish this from emergency rolling blackouts, giving operators a window to shed load gracefully rather than face abrupt power loss.

For operators of large data centers in PJM territory, the calculus is now concrete. Facilities above 50 MW will need to plan for the possibility of curtailment events beginning next summer, with notice that could be as short as 30 minutes. The compensation framework softens the financial blow, but it does not address the operational complexity of shedding a substantial fraction of load on short notice. Data centers with backup generation face the additional prospect of being asked to disconnect from the grid entirely and run on their own power during emergencies.

The broader context here is that grid planning assumptions built over two decades of flat or declining electricity demand have been overturned in roughly three years. PJM's territory is absorbing load growth at a pace that new generation and transmission builds cannot match, and the operator is now restructuring its market design to treat large flexible loads as a managed resource rather than a passive drain on the system. The special report's language about second-scale demand response envisions data center workloads functioning as a form of virtual peaking capacity — essentially, a way to reduce demand fast enough to substitute for firing up an additional power plant.

Whether the industry's workload orchestration tools, power distribution architectures, and service-level commitments can actually deliver that level of coordination at grid scale is an open engineering question. The June 2027 start date gives affected operators roughly a year to prepare. PJM is simultaneously working the supply side, running additional capacity auctions to close the shortfall from earlier rounds. Both threads, demand-side flexibility and supply-side procurement, will need to converge to keep the grid stable as data center load continues its steep upward trajectory across the PJM footprint.