Data centers along the Dulles Toll Road corridor could face mandatory power cutbacks on the hottest and coldest days under a new federal proposal from the regional grid operator.

PJM Interconnection, which manages the electric grid for 67 million people across 13 states including Virginia, filed the plan with the Federal Energy Regulatory Commission (FERC) on Thursday, Aug. 13. The rule, called Interim Resource Adequacy Service (IRAS), would require new large-load customers drawing at least 50 megawatts at a single site to pay directly for new energy capacity added to the grid.

Data centers that haven't secured their own power would be first in line for load-shedding during peak demand, the Virginia Mercury reported. They'd be moved onto backup generators or asked to reduce consumption before existing customers feel any impact.

Christopher Pilong, PJM's senior director of operations planning, said in an affidavit accompanying the filing that "IRAS provides a new step, at PJM's disposal, prior to impacting existing customers," as POWER Magazine reported.

The 50-megawatt threshold is roughly the size of a mid-sized data center campus. Northern Virginia's "Data Center Alley," which stretches along the Dulles Toll Road corridor through Reston, hosts at least 570 data centers statewide and serves as one of the world's most important internet hubs.

Why now

FERC on June 18 ordered all six U.S. regional grid operators to justify or rewrite their rules for connecting very large customers. PJM was the first to respond.

The urgency is real. PJM's two most recent capacity auctions both cleared short of reliability requirements. The 2028/2029 auction came up 6,831 megawatts short at the FERC-approved price cap of $325 per megawatt-day, according to Utility Dive. PJM projects data center and other large-load demand could grow by up to 70 gigawatts across its territory by 2038.

That demand is already hitting wallets. PJM projected a $6.3 billion increase in consumer electricity costs over the next three years, mostly attributable to data center demand. Virginia's residential electricity rate rose 15.4% between May 2025 and May 2026, climbing from 15.26 cents to 17.61 cents per kilowatt-hour.

Layered pressure on the corridor

The PJM filing adds a federal layer to state-level actions already targeting data center costs. Virginia's State Corporation Commission on Wednesday, Aug. 5 ordered Dominion Energy to develop a new tariff requiring data centers to cover most transmission infrastructure costs they require. Gov. Abigail Spanberger said the state is taking steps to make data centers pay their fair share of energy costs.

As we reported Aug. 26, regional leaders discussed the shifting data center landscape at the Northern Virginia Regional Elected Leaders Summit. Arlington County Board Chair Matt de Ferranti said at the Aug. 26 summit, "The next 10 years on data centers look very different for Northern Virginia than the last 20 years did."

What happens next

PJM asked FERC to approve the changes by Oct. 12, which would allow the framework to take effect June 1, 2027. PJM also plans to create a registry of large-load customers tracking location, peak demand, planned growth, backup generation and qualifying new capacity.

Data centers directed to reduce power under the rule would receive a financial credit at up to 50% of PJM's Non-Performance Charge Rate for helping maintain grid reliability.

Environmental groups are watching closely. The Piedmont Environmental Council and Sierra Club sent a letter to Spanberger asking for rules requiring public notification when backup generators activate, citing four separate emergency orders from the U.S. Department of Energy in 2026 that allowed generators to exceed approved emissions limits.

No Reston-area data center operator has publicly commented on the IRAS proposal. PJM asked FERC to rule within 60 days of the Aug. 13 filing, putting a decision around Oct. 12.