DOE and Montana release Final Environmental Impact Statement for 422-mile North Plains Connector transmission line

On August 28, 2026, the U.S. Department of Energy and Montana’s Department of Environmental Quality jointly released the Final Environmental Impact Statement for the proposed North Plains Connector—a 422-mile high-voltage transmission line planned to run between Colstrip, Montana, and North Dakota.

The document marks a significant milestone in the federal and state review process for a project that aims to connect the country’s separate eastern and western power grids at a major scale.

DOE and Montana publish final environmental review for North Plains Connector

The DOE and Montana’s DEQ released the FEIS on August 28, 2026, acting together as Joint Lead Agencies throughout the review. DOE Assistant Secretary for the Office of Electricity, Catherine Jereza, was direct about what the document represents. “Connecting our nation’s eastern and western power grids is a critical step toward ensuring long-term energy affordability and reliability for millions of Americans,” she said.

The agencies cited the need to increase transfer capacity and expand access to diverse generation sources as the primary drivers behind the proposal.

The FEIS is the product of a coordinated federal and state environmental review—and its release signals the project has cleared one of the most demanding regulatory requirements in the permitting process. That said, it doesn’t mean the project is approved yet.

Why the North Plains Connector is being proposed

Electricity demand is rising. In Montana, North Dakota, and across the country, existing grid infrastructure is increasingly being stretched to meet that demand. The agencies cited the need to increase transfer capacity and expand access to diverse generation sources as the primary drivers behind the proposal.

Part of the challenge is structural. The U.S. currently operates two largely separate power grids—the Western Interconnection and the Eastern Interconnection—with very limited ability to exchange electricity between them. When one region has a surplus and another has a shortfall, moving power across that divide is difficult, if not impossible, under the current setup. The North Plains Connector is designed to address that directly by building a physical link between the two systems.

Technical specifications of the proposed transmission line

The North Plains Connector would be a 422-mile, 525-kilovolt high-voltage direct current (HVDC) overhead transmission line running between Colstrip, Montana, and a point in North Dakota—a route that spans the geographic boundary between the two interconnections.

HVDC technology is well-suited for long-distance transmission. Unlike alternating current lines, HVDC systems move large amounts of electricity over long distances with lower energy losses, and they can connect grids that operate at different frequencies. The line would provide 3,000 megawatts of bidirectional transfer capability, meaning electricity can flow west to east or east to west depending on where it’s needed at any given moment.

Expected effects on grid reliability and regional energy supply

Connecting the two grids is expected to make the broader system more resilient. When severe weather knocks out generation capacity in one region, a connected grid can draw power from the other side—reducing the risk of prolonged outages for communities.

That bidirectional capability matters most during peak demand periods. Think extreme heat waves or cold snaps: grid operators could reroute electricity from wherever supply is available, a kind of flexibility that’s much harder to achieve when the two grids are running in isolation. Department of Energy officials also framed the project in terms of long-term affordability. Jereza said expanding transmission capacity ensures “electricity can move where and when it’s needed most,” which can help stabilize costs for consumers in Montana, North Dakota, and beyond. Access to a wider pool of generation sources tends to put downward pressure on prices over time.

Background: The federal and state review process

An Environmental Impact Statement is a legally required document under the National Environmental Policy Act, commonly known as NEPA. Federal agencies must complete this review before approving any major project that could have significant environmental consequences. The process involves public comment periods, technical analysis, and coordination across agencies.

The FEIS is the final stage of that review. It incorporates responses to public and agency comments received on the draft version and represents the agencies’ complete assessment of the project’s potential environmental effects. Releasing it clears a significant regulatory hurdle—but additional decisions and authorizations are still required before construction could begin.

The DOE’s Office of Electricity led the federal side of this process, coordinating with the MTDEQ throughout. That joint structure is reflected in their shared role as co-lead agencies on the document.

Carrying up to 3,000 megawatts of electricity in both directions

The release of the Final Environmental Impact Statement moves the North Plains Connector forward, but the project still has regulatory ground to cover before it becomes a reality.

The proposed line is 422 miles long, runs at 525 kilovolts, and would carry up to 3,000 megawatts of electricity in either direction between Montana and North Dakota. It would be the first physical link between the U.S. Eastern and Western Interconnections at this scale.

The FEIS was jointly released by the DOE and Montana’s DEQ on August 28, 2026. It satisfies a core requirement under NEPA but doesn’t constitute project approval—further permitting steps remain. The DOE’s Office of Electricity continues to oversee the federal permitting process as the project moves forward.

Kelly Lippke

Kelly is an experienced writer with 15 years of experience exploring the big stories that shape our world, from tech breakthroughs and space exploration to climate, energy, and the fascinating quirks of science. She has a talent for turning complex ideas into sharp, memorable insights that stay with readers long after they’ve finished reading.