AINEWS
Data centers drove half of US electricity demand growth in 2025, and the next constraint is natural gas: a cold snap will test the contracts, not the power plants.
The Appalachia-to-Virginia gas spine is at the wall. Data centers drove roughly half of US electricity demand growth in 2025, and the next binding constraint in the AI power story is no longer electrons on a wire. It is molecules in a pipe.
The scale arrived in a single IEA figure. Data centers accounted for 50 percent of US electricity demand growth in 2025, the agency's first formal read on the post-2024 buildout. Natural gas, which the Energy Information Administration puts at 39 percent of US electricity production, is the fuel doing the load-following. Pair the two and the generation problem becomes a molecule problem in about eighteen months.
Northern Virginia's "Data Center Alley," the cluster of hyperscale campuses around Ashburn and Loudoun County, is where the constraint shows up first. Williams Companies is expanding its Transco pipeline system through the region, threading more capacity under the country's largest concentration of new data-center load. The Williams Transco Southeast Supply expansion has been in front of FERC through early 2026, and trade-press reporting points to an early in-service target. A separate Transco expansion announced in mid-2025 is sized for the same demand.
Adjacent peakers are the other half of the work-around. Developers are proposing gas-fired power plants sited directly next to data-center campuses, in effect building behind-the-meter generation to bypass the PJM interconnection queue. The result is a new physical pattern: a data center, a gas plant, and a short pipeline tap, with the broader regional grid carrying less of the load than the campus siting would suggest.
What "more pipe" actually means is the part the wire coverage tends to skip. Henry Froats, owner of Hydrotech Testing Services, estimates the US needs roughly 25 percent more natural-gas infrastructure than it currently has to handle electricity generation and data-center demand over the next 25 years. The figure covers more than trunk lines. It includes compressor stations, processing plants, storage, metering, and last-mile connections to generators, export terminals, and local distribution companies. Each of those layers has its own permitting clock.
The cold-snap test is the unresolved question. Ian McPhillips, director of energy engineering and principal at BL Companies, warns that when temperatures fall, gas-fired generators and Northeast space-heating customers compete for the same firm supply. The dispatch and contracting logic that worked when the gas system had slack was built for a different demand mix. The IEA's Energy and AI report flags the same bottleneck in its 2025 scenario work, treating firm-gas availability for power generation as one of the binding constraints on the AI buildout.
The market-design question is sharper than the buildout question. Major gas infrastructure takes five to fifteen years from open season to in-service, and is now being raced by a data-center demand cycle that books campuses on eighteen-month timelines. Even with Williams' Transco expansions landing on schedule, the next stress event will not be a megawatt shortfall. It will be a contract question: which loads get cut when a polar vortex pushes home heating and gas-fired generation to peak at once, and which firm-gas agreements were actually written for that test.
Williams' Transco Southeast Supply project is the first scheduled test of the new demand curve. The early in-service dates in the FERC docket and the 2025 capacity announcement are the cleanest signal of how quickly the molecule side of the AI power story is moving. The harder test, the one that will set contract terms for the next decade, will arrive with the first sustained cold snap over the Northeast.