The U.S. Department of Energy's (DOE) Office of Electricity has released a draft of the 2026 National Transmission Needs Study, opening a 60-day public comment period on a report that identifies areas where additional electric transmission infrastructure will be needed to support growing electricity demand and maintain grid reliability.

Required under the Federal Power Act, the study—formerly known as the National Electric Transmission Congestion Study—examines current and anticipated transmission constraints across the U.S. electric grid. According to DOE, the findings are intended to inform transmission planning and investment decisions by identifying areas of congestion, capacity limitations and opportunities to improve grid reliability and reduce system costs.

The draft study concludes that significant transmission expansion will be needed as electricity demand increases due to data center development, domestic manufacturing, large industrial loads and broader economic growth.

"Electricity demand is accelerating faster than anything we've seen in decades, driven in part by data centers, manufacturing growth, and new forms of industry that are emerging almost by the month," said Catherine Jereza, assistant secretary for DOE's Office of Electricity. She said the study highlights the need for collaboration among local communities, states, Tribal Nations, industry and regional reliability organizations on future transmission planning.

Among the draft report's key findings:

• Transmission expansion is needed to support growing demand. DOE found that increasing electricity consumption from data centers, manufacturing, industrial facilities and electrification is creating a need for additional transmission capacity to accommodate new generation, connect new loads and relieve congestion. The report notes that most transmission congestion occurs during about 5% of annual hours, particularly during periods of high day-ahead and real-time market price differences, high net load, cold weather and elevated levels of intermittent renewable generation. Within-region transmission projects in the New York Independent System Operator (NYISO), NorthernGrid South and the Midcontinent Independent System Operator (MISO) could provide significant congestion relief.
• Interregional transmission can improve reliability and resilience. The study identifies additional value in expanding transmission between regional grids, citing benefits that include improved reliability, greater resilience and the ability to meet growing demand in areas facing capacity constraints. Based on historical locational marginal price data, DOE found that transmission links between the Western and Eastern Interconnections, as well as between NorthernGrid and WestConnect and between ISO New England and NYISO, show strong potential for reducing congestion costs.
• Regional grid operators are expanding transmission investment. According to the report, several Regional Transmission Organizations (RTOs) and Independent System Operators (ISOs) have recently approved some of their largest transmission investment portfolios. These include the Midcontinent Independent System Operator (MISO), Southwest Power Pool (SPP), PJM Interconnection and the Electric Reliability Council of Texas (ERCOT). DOE noted that MISO approved the largest transmission portfolio in U.S. history in 2024.

DOE is seeking input from utilities, state agencies, Tribal Nations, regional reliability organizations, local communities and other stakeholders. The agency also plans to hold in-person roundtable discussions across the country during the summer of 2026 before finalizing the study.

The public comment period closes Sept. 7, 2026. DOE has also made an informational webinar about the draft study available through its Office of Electricity