Final EIS moves 525-kilovolt line linking Western and Eastern power grids closer to construction approval
The Montana Department of Environmental Quality has issued a Final Environmental Impact Statement for the North Plains Connector Project, a major transmission line proposed to link the Western and Eastern U.S. electrical grids, clearing a key hurdle in the state’s permitting process.
The review, conducted by DEQ with the U.S. Department of Energy as a co-lead agency, was completed in compliance with the Montana Environmental Policy Act. The document, now posted on DEQ’s website, analyzes the project’s potential environmental impacts.
The project calls for construction of an overhead transmission line carrying 525 kilovolts of high-voltage direct current, with capacity to move 3,000 megawatts of electricity between the two grids. The line would begin near Colstrip, Mont., and run through Rosebud, Custer and Fallon counties before terminating at two points near Center and St. Anthony, N.D.
DEQ received the developer’s application for a Certificate of Compliance under the state’s Major Facility Siting Act on Sept. 18, 2024, kicking off a review that has spanned roughly two years. The process included two public comment periods, one during the scoping phase before the environmental impact statement was drafted and a second after the draft was released.
The Final EIS incorporates DEQ’s responses to substantive comments submitted on the draft document. State law requires the agency to wait 15 days after publishing the Final EIS before issuing a Record of Decision and the Major Facility Siting Act certificate. That certificate is required before construction on the project can begin.