Largest US power grid will cut electricity to data centers during shortages, forcing AI builders to find their own power

The Grid Just Told AI Builders: Your Power Isn't Guaranteed

When the largest electricity grid in the United States tells data centers they will lose power during shortages, the message to the AI industry is direct: guaranteed electricity is no longer part of the deal.

PJM Interconnection, the grid operator serving 67 million customers across territory from Virginia to Illinois, will begin curtailing power to data centers and other large users during electricity shortages starting June 2027. The cuts apply to data centers consuming 50 megawatts or more, and affected customers will be compensated through structures similar to the demand-response programs that have served large industrial users for decades. 1

The trigger was a capacity auction that fell short of securing enough new generating resources. The backdrop is starker: wholesale electricity prices across PJM territory have nearly doubled over the past year, and PJM's independent market monitor has attributed much of the increase to data center demand. 1

For grid operators, curtailing the largest and most flexible users during shortages is standard practice. For the companies spending hundreds of billions on AI infrastructure, it changes the underlying assumption of the buildout.

Every capex forecast driving the current wave of AI investment depends on one premise: that electricity will be available when the GPUs need it. PJM has now put a condition on that premise, and its territory covers the heart of the country's data center construction, including Northern Virginia.

When curtailment events hit, data centers that cannot rely on grid power will turn to their own generation. Many data centers already favor diesel backup generators, since diesel fuel is widely available and can be stored on-site. 1 Under federal EPA RICE NESHAP regulations, those generators may operate up to 100 hours annually for non-emergency purposes including maintenance, testing, and demand response. 2

That push toward on-site diesel collides directly with another story unfolding the same week. Vantage Data Centers faced scrutiny for its apparent coordination with Virginia environmental regulators to cast doubt on a report linking diesel backup generators at a 96-megawatt facility in Northern Virginia to tens of millions of dollars in annual health damages for nearby residents. 1

The grid's curtailment policy is pushing data centers toward the exact generators whose community health costs are now publicly disputed.

The scale ensures this is not a temporary squeeze. By 2035, data centers are expected to consume four times more electricity than they do today. 1 PJM is running another capacity auction to close the gap, but the structural issue is the gap itself: data centers are being built faster than new power plants and transmission lines can be approved and constructed.

That gap is already reshaping how AI companies plan for power. The signals have been accumulating across the industry: agreements for dedicated nuclear generation, behind-the-meter power projects, and a shift in data center siting toward locations near existing power infrastructure. 34 PJM's curtailment plan converts what was a strategy into a requirement.

What remains unpriced is the cost. On-site generation adds capital expense to facilities that are already among the most expensive buildings ever constructed. Diesel generators push environmental and health costs onto surrounding communities. And the compensation PJM will offer for curtailment, modeled on demand-response programs designed for factories that can throttle a production line, may not cover the cascading losses of a data center sitting idle while a multi-million-dollar training run stalls or inference latency spikes for end users.

The AI buildout has operated on the assumption that compute is the bottleneck. PJM's decision makes clear that in the regions where data centers concentrate most heavily, electricity is the constraint, and the grid will protect residential and commercial customers before it protects a server farm.