PJM Grid to Cut Power to Large Data Centers Starting 2027

PJM Interconnection, the largest electrical grid in the United States, has announced it will temporarily cut power to data centers and other large users during supply shortages beginning June 2027. The move comes after a capacity auction fell short and reflects the strain that rapid data center growth is placing on a system serving 67 million customers from Virginia to Illinois.

Why PJM Is Pulling the Plug on Big Data Centers

The grid operator's territory has seen an onslaught of new data center construction, driven by AI workloads and cloud demand. By 2035, data centers are projected to consume four times the electricity they use today. That trajectory collided with a recent capacity auction that failed to secure enough new generating resources, leaving PJM with a tighter reserve margin than it considers safe.

PJM's independent market monitor has already blamed data centers for much of the near-doubling of wholesale electricity prices over the past year. The curtailment plan targets only facilities of 50 megawatts or larger — a threshold that captures hyperscale campuses while sparing smaller colocation sites.

How the Demand Response Program Works

This isn't a novel concept. Demand response programs have existed for decades, typically enrolling large industrial users like manufacturers. The mechanics are straightforward:

• Advance notice: Participants receive warning ranging from 30 minutes to several days, depending on forecast accuracy.
• Compensation: Customers who lose power are paid for their participation, offsetting some operational disruption.
• Trigger: Curtailment activates only during declared power shortages — not as a routine measure.

The program gives PJM a controllable load resource it can dispatch when generation falls short, effectively turning big consumers into a virtual power plant.

The Diesel Generator Dilemma

Faced with the prospect of involuntary outages, many data centers — both new and existing — will likely invest in on-site generation. Those that don't will lean harder on backup generators, which are costlier to operate and frequently more polluting than grid power.

Diesel generators remain the default choice because fuel is widely available and can be stored on-site. Federal regulations permit their use for up to 50 hours per year for demand response events and up to 100 hours per year for emergencies and maintenance. But those hours add up across a region dense with facilities, raising local air quality concerns.

Vantage Data Centers and the Virginia Controversy

This week, Vantage Data Centers drew criticism for its apparent coordination with Virginia environmental regulators to challenge a report estimating that diesel backup generators at a 96-megawatt Northern Virginia facility could cause tens of millions of dollars in annual health damages for nearby residents. The episode underscores a growing tension: grid reliability measures that push operators toward diesel may conflict with community health priorities.

What This Means for the Grid and Prices

PJM is running another capacity auction to attract new generation, but the structural imbalance — soaring demand from data centers versus slower supply additions — won't resolve quickly. Wholesale prices have already nearly doubled, and the curtailment program is essentially an admission that the grid cannot currently guarantee firm service to its largest new customers without emergency measures.

For data center operators, the calculus shifts: on-site renewables, batteries, or even small modular reactors start looking more economical against the backdrop of uncertain grid supply and rising energy costs. For ratepayers across the PJM footprint, the hope is that demand response and new generation eventually stabilize prices — but the next few years will be a stress test.

Key Takeaways

• PJM will curtail power to data centers ≥50 MW starting June 2027 during supply shortages.
• Participants receive compensation and advance notice (30 minutes to days) — standard demand response mechanics.
• Diesel backup generators fill the gap but are costlier, dirtier, and federally limited to 50–100 hours/year.
• Wholesale prices have nearly doubled; PJM's market monitor attributes much of the increase to data center load.
• On-site generation investment will accelerate as operators hedge against grid uncertainty.

Looking Ahead

The next capacity auction will signal whether new generation — gas, renewables, or storage — can close the gap. Meanwhile, expect more friction between grid operators, data center developers, and local communities over air quality, land use, and who bears the cost of keeping the lights on. The 2027 curtailment start date isn't far off; how the ecosystem adapts before then will shape the next decade of digital infrastructure in the Mid-Atlantic and Midwest.