DOE finalizes environmental review of North Plains Connector transmission line
The US Department of Energy finalized its environmental review of the 420-mile North Plains Connector, a 3,000 MW line linking three grid regions.
Photo by Petr Ganaj on Pexels
The US Department of Energy and the Montana Department of Environmental Quality released the final environmental impact statement for the North Plains Connector transmission line on August 28, 2026, clearing a key federal hurdle for a 420-mile high-voltage line designed to link three separate US grid regions. Developed by Grid United, the project would carry 3,000 megawatts (MW) of power bidirectionally between Montana and North Dakota, connecting the Western, Eastern and Great Plains grid interconnections for the first time at this scale, according to the DOE’s project record (DOE/EIS-0568).
What the project would build
The North Plains Connector is designed as a 525-kilovolt (kV) high-voltage direct-current (HVDC) overhead line running approximately 420 to 422 miles from near Colstrip, Montana, to two separate endpoints in North Dakota, near Center and near St. Anthony, plus associated alternating-current (AC) transmission lines and converter stations. The line would interconnect three grid regions operating on different timing and reliability standards: the Western Electricity Coordinating Council (WECC), the Southwest Power Pool (SPP), and the Midcontinent Independent System Operator (MISO), according to DOE’s project documentation and reporting by Canary Media. Estimated project cost is approximately $6 billion, with earliest completion projected for 2032.
Federal funding and utility backing
The DOE awarded a $700 million grant to the North Plains Connector consortium, made up of Grid United and the Montana Department of Commerce, in 2024. That federal support continued through the transition between the Biden and Trump administrations, an unusual instance of transmission-project continuity across a change in administration, Canary Media reported. Several regional utilities have signed conditional financial commitments to the project, including Minnkota Power Cooperative, NorthWestern Energy, Allete Energy, Great River Energy, Portland General Electric and Puget Sound Energy. DOE’s draft National Transmission Needs Study, published in July 2026, cited the North Plains Connector as a priority interregional asset for national grid reliability.
| Project detail | Figure |
|---|---|
| Line length | About 420-422 miles |
| Voltage / type | 525 kV HVDC |
| Transfer capacity | 3,000 MW bidirectional |
| Grid regions linked | WECC, SPP, MISO (3 total) |
| Estimated cost | About $6 billion |
| DOE grant (2024) | $700 million |
| Final EIS released | August 28, 2026 |
| Earliest completion | 2032 |
Source: US Department of Energy, DOE/EIS-0568 Final Environmental Impact Statement, August 28, 2026; Canary Media, September 3, 2026.
Why interregional links matter for reliability
Grid operators and federal regulators have increasingly pointed to interregional transmission as a way to move surplus renewable and thermal power across time zones and weather patterns, reducing the risk of regional shortfalls during extreme weather. Winss Solutions has previously covered how US states took 481 grid modernization actions in the second quarter of 2026 and how FERC cleared the Southwest Power Pool to reroute power around grid congestion, both part of the same broader push to relieve transmission bottlenecks that can otherwise force renewable curtailment or strain reliability during peak demand.
Background
Grid United is a transmission development company focused on large interregional HVDC lines connecting previously unconnected or weakly connected parts of the US grid. The North Plains Connector traces back to a Notice of Intent to prepare an environmental impact statement published in the Federal Register in October 2024, followed by a draft EIS in January 2026 and the final EIS in August 2026. The project has drawn both support, from utilities seeking additional transfer capacity and reliability, and opposition in some states during the federal review process, according to regional energy trade coverage. With the final EIS complete, the project moves toward final permitting and financing decisions ahead of an earliest possible in-service date of 2032.
Sources: US Department of Energy; Canary Media; Daily Energy Insider
Featured image: photo by Petr Ganaj on Pexels (free Pexels license).
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I specialize in sustainability education, curriculum co-creation, and early-stage project strategy. At WINSS, I craft articles on sustainability, transformative AI, and related topics. When I’m not writing, you’ll find me chasing the perfect sushi roll, exploring cities around the globe, or unwinding with my dog Puffy — the world’s most loyal sidekick.
