America's largest power grid tells data centers it can cut their power

America's largest power grid operator has delivered a blunt message to the data center industry: if you want power fast, you must accept that we can take it away.

PJM Interconnection, the grid operator that coordinates electricity delivery to roughly 65 million people across 13 states and Washington, D.C., has formally updated its tariff rules to allow it to curtail power to data centers and other large industrial loads during emergency grid conditions. The change, filed with and accepted by the Federal Energy Regulatory Commission (FERC), creates a structural mechanism for shedding load from facilities that sign up for an expedited interconnection process.

The rule is a direct consequence of the AI boom. Data centers, which house the graphics processing units required to train and run large language models, have created a surge in electricity demand with few historical precedents. Northern Virginia, home to the region known as Data Center Alley, hosts a significant share of the world's internet traffic and has become the epicenter of the strain on PJM's system.

For years, data center developers waited years to connect to the grid, with transmission queue times ranging from four to seven years in many PJM zones. Frustrated by those delays, major technology companies began petitioning grid operators and state regulators for faster interconnection. PJM's response: a new service class that allows data centers to jump the queue, but at the price of interruptibility.

A trade-off: speed for reliability

Under the new rules, large loads that choose the expedited interconnection path are classified as curtailment-eligible resources. That means when PJM's operators determine that the grid is under stress, during extreme heat waves, generation outages, or transmission failures, they can order these facilities to reduce consumption within minutes.

The logic is straightforward. PJM's primary obligation is reliability: keeping the lights on for hospitals, homes, and essential services. Data centers, by contrast, are not considered critical infrastructure from a public safety perspective. If the grid must choose between a hospital and a server farm, the server farm loses.

But for data center operators, the implications are significant. A sudden curtailment can mean interrupted training runs, corrupted data, downtime for cloud services, and substantial revenue losses. Many data centers have backup generators, but those are typically designed for short outages, not sustained grid emergencies that could last hours.

The demand shock behind the decision

The urgency of PJM's move is hard to overstate. In 2025, PJM's annual capacity auction cleared at record prices, in some areas exceeding $400 per megawatt-day, a tenfold increase from prior years. The market signal was unambiguous: the grid is running out of available generation capacity to keep pace with demand growth.

PJM's own projections suggest that data centers could add tens of thousands of megawatts of new demand in the next five years. In Virginia alone, utility Dominion Energy has revised its long-term demand forecast upward by more than 30 percent, driven almost entirely by data center development.

The grid operator's hand was also forced by a growing political backlash. State regulators in Virginia, Ohio, and other PJM member states have grown uneasy with requests from tech companies to bypass standard interconnection procedures. Meanwhile, consumers have pushed back against the prospect of rate increases to fund transmission upgrades designed primarily to benefit data center developers.

Industry reaction: a nuclear option?

Data center industry groups have reacted with a mixture of shock and pragmatism. The curtailment rule is what some operators call the nuclear option: a tool that could ultimately undermine the very economic growth that data centers bring to their host regions. If the largest employers in an area cannot count on reliable power, industry advocates argue, they will simply build elsewhere.

Several major technology companies have responded by investing in their own power generation. Amazon, Google, and Microsoft have signed power purchase agreements with solar, wind, and even nuclear generation facilities. In some cases, these companies are effectively becoming their own utilities, building microgrids that can operate independently of the wider grid.

But those strategies work only for new developments with deep capital reserves. Smaller data center operators, and the enterprise customers who depend on them, lack the resources to build dedicated generation. For them, the new rule introduces significant operational risk and complicates the service-level agreements they offer to their own customers.

A precedent for other grids

PJM's decision could set a precedent for other grid operators facing similar pressures. The Electric Reliability Council of Texas (ERCOT), which operates the state's main grid, has historically pushed large industrial consumers to reduce usage during peak events through voluntary, compensated programs. But persistent tight reserve margins in Texas have raised the question of whether mandatory curtailment is inevitable there as well.

The change also reshapes the traditional relationship between electricity markets and large industrial customers. Historically, big loads were passive participants in the power system, consuming electricity and paying for it, with reliability obligations resting entirely on grid operators and generators. Now, on a wide scale for the first time, the largest electricity consumers are being asked to function as flexible resources that can be shed when needed.

What experts are saying

Supporters of the rule, including reliability analysts, argue that the curtailment provision will rarely be used. Grid operators typically exhaust other measures first, including voluntary conservation appeals and economic dispatch of standby generation. The rule, in effect, is an insurance policy against a worst-case scenario: a grid emergency so severe that the only alternatives are blackouts for everyone or targeted curtailment for data centers.

Critics contend that the rule lets grid operators and utilities off the hook. Rather than building the transmission and generation needed to meet demand, they argue, the system shifts the risk onto a single class of customers. Consumer advocates also worry that curtailment mechanisms will allow data centers to secure faster interconnection while existing ratepayers continue to fund the grid upgrades that make the expedited hookups possible.

Some energy policy experts see a deeper economic signal. The grid is saying that unlimited, unconstrained power is no longer available to everyone at all times. That is a structural change in the economics of electricity, and the market will have to price it accordingly. The same logic may soon extend to other demand sources, including cryptocurrency mining operations, which have already faced emergency curtailment in several regions.

What happens next

The new rules take effect as data center interconnection requests continue to flood PJM's queue. Observers expect the expedited lane to remain popular despite the curtailment exposure, because time-to-market for AI computing capacity is extraordinarily valuable. But the market will ultimately test how much risk data center operators are willing to accept.

Some analysts expect a market for curtailment insurance to emerge, along with specialized demand-response aggregators that help data centers manage their exposure. Others foresee new business models in which data center workloads are designed to be discretionary, with AI training jobs that can pause and resume without catastrophic data loss.

There is also the question of how the rule interacts with state-level clean energy mandates. Several PJM member states have aggressive decarbonization goals, and data centers are often considered key economic development anchors. Whether states will fight the curtailment rule or quietly accept it as the price of hosting digital infrastructure remains an open question.

One thing is clear: the era of data centers as untouchable electricity consumers has ended. America's largest grid has drawn a line, and every other grid with rising data center demand will have to decide where its own line sits. For the data center industry, the message from PJM is unambiguous: power is no longer an entitlement, but a negotiated privilege.