NorthWestern Energy has signed a nonbinding memorandum of understanding with North Plains Connector, a wholly owned entity of Grid United, to own 10% (300 MW) of North Plains Connector, a 3,000-MW, 420-mile HVDC transmission line to be constructed with endpoints near Bismarck, North Dakota, and Colstrip, Montana.

While Grid United and ALLETE are together developing North Plains Connector, Avista, Portland General Electric and Puget Sound Energy also have ownership MOUs with North Plains Connector. The project is entering the permitting phase and initiating regulatory filings with approvals targeted in 2026. Construction is expected to begin in 2028 and the project will be operational by 2032.

As per the terms of the MOU, Grid United will continue to fund the development of North Plains Connector and NorthWestern Energy will invest after the project received regulatory approvals and permits.

"NorthWestern Energy's Colstrip, Montana substation is strategically located and will serve as a critical endpoint for North Plains Connector, reinforcing Colstrip's position as an essential energy hub," said NorthWestern Energy President and CEO, Brian Bird. "The North Plains Connector developer's collaborative approach with Montana communities to address concerns and ensure the footprint reflects local priorities aligns with NorthWestern Energy's commitment to our customers."

In early 2024, NorthWestern Energy supported the Montana Department of Commerce as part of the North Plains Connector Interregional Innovation (NPCII) consortium in its application for a $700 million grant from the U.S. Department of Energy's Grid Resilience and Innovation Partnership (GRIP) program. The NPCII includes an upgrade of the Colstrip Transmission System and while the majority of the grant is allocated for the North Plains Connector, it also includes funding for an upgrade of the Colstrip Transmission System, jointly owned and operated by NorthWestern Energy.

NorthWestern Energy and Grid United have also entered into a letter of intent to continue transmission development to further enhance the grid through the southwest corridor of Montana. Development to expand the southwest corridor of Montana through grid buildout will help improve the connectivity between Montana and the broader Western energy market, bolstering grid reliability, allowing for critical import capability and enabling customers to access and benefit from emerging energy markets in the West.