DOE’s Draft 2026 National Transmission Needs Study: Congestion, Seams and Data-Centre Load

In July 2026 the United States Department of Energy released a draft National Transmission Needs Study for consultation and public comment under section 216(a)(1) of the Federal Power Act. The study identifies present or expected transmission capacity constraints or congestion that harm or may harm consumers and that transmission solutions could alleviate. DOE reports that transmission investments energised between 8,700 and 12,500 circuit-miles each year from 2016 to 2023, producing a national total of 85,000 circuit-miles of newly constructed, upgraded or rebuilt lines rated above 69 kilovolts between 2016 and 2024.

About 40 percent of those circuit-miles were driven by reliability needs, with load growth, aging infrastructure and generation interconnection also important. The draft cites estimated United States transmission congestion costs of 11 billion dollars in 2023, down from a high of 21 billion dollars in 2022 associated with natural gas price spikes and severe weather such as Winter Storm Elliott. Lawrence Berkeley National Laboratory analysis summarised in the study finds the highest congestion value on links that cross market seams or interconnections. Use it to pressure regional and interregional planning processes aligned with Order No. 1920.