The US’ largest grid operator, PJM Interconnection, has approved an $11.8 billion transmission expansion plan to keep up with surging data center connection requests across its footprint.

The Regional Transmission Operator (RTO) serves all or parts of 15 states across the East Coast and South of the US.

The PJM board approved the plan under its 2025 Regional Transmission Expansion Plan (RTEP) Window 1, with a large share tied to load growth in data center-heavy regions.

Of the total, roughly $4.8bn is allocated to projects across Virginia utility Dominion Energy’s coverage area.

PJM said the upgrades are required to maintain reliability amid accelerated load growth across its Mid-Atlantic and Midwest footprint. In addition to rising demand, the plan addresses new generation in southern Virginia, future generation in western PJM, delays to offshore wind projects in New Jersey, and increasing power flows toward the eastern portion of the grid, where Northern Virginia’s data center cluster is located.

A central component of the expansion is Dominion Energy Virginia’s proposed $2.3bn, 525kV underground “backbone” transmission line spanning 185 miles (297km) across Virginia. The project, targeted for service by June 2032, also includes two high-voltage direct current converter stations that will cost approximately $1.5bn.

The transmission line is designed to deliver approximately 3GW of power into Loudoun County, Northern Virginia, which has the world's largest concentration of data centers. Like other multi-zone expansions, the costs are expected to be shared across the operator's footprint.

The plan also includes a $1.7bn transmission line across central Pennsylvania proposed by NextEra Energy Transmission and Exelon. According to the utilities, the project is expected to address structural reliability needs in PJM’s northeastern region and is expected to enter service by June 2031.

In central Ohio, Grid Growth Ventures, a joint venture between Transource Energy - a partnership between American Electric Power and Evergy - and FirstEnergy Transmission, will develop a $1.1bn project that comprises 300 miles (482km) of 765kV lines.

Additional projects include around $580 million of upgrades by PPL Electric and roughly $276m and $292m by Exelon subsidiaries Commonwealth Edison and Potomac Electric Power Co., respectively.

PJM’s 2025 baseline plan is significantly higher than prior years, following $5.9bn in approved projects in 2024 and $6.6bn in 2023, indicating that data center demand is driving the need for massive investments in transmission infrastructure.

PJM has increasingly been in the hot seat due to the exponential growth of demand across its footprint. Earlier this month, it was reported that the grid operator could face a power supply shortfall of up to 60GW.

In December, the RTO reported a 6.5GW shortfall in its latest capacity auction. As a result, PJM warned that there is not enough generation at present to meet peak demand plus required reserves for the year starting mid-2027.

These fears have spurred action within the federal government, with President Donald Trump calling on PJM to hold an emergency power auction that would see data center operators foot the bill for the construction of new power generation infrastructure.

Under the terms of the initiative, the Trump administration and governors within the PJM Interconnection market will push the RTO to launch a reliability power auction, giving tech companies and hyperscalers the chance to bid on 15-year contracts for new electricity generation. According to reports, if the plan were to go ahead, it could award contracts worth more than $15bn to build new power plants.