NorthWestern Energy announced Tuesday it has reached a deal to acquire a 370-megawatt share in the Colstrip coal plant, making the Montana-based utility the largest shareholder in the plant.
The utility will take over the share of fellow co-owner Puget Sound Energy at no cost effective Jan. 1, 2026, according to a news release from the utility, the largest in Montana.
It's the second major acquisition by NorthWestern in recent years after the utility announced it would acquire 222 megawatts from co-owner Avista Corp.
The acquisition will also finalize on Jan. 1, 2026, giving NorthWestern Energy a 55 percent majority stake in Colstrip.
The current majority stakeholder, Talen Energy, had originally made a deal to buy Puget Sound Energy's stake in 2022, but that deal fell apart in the wake of Talen's bankruptcy declaration.
Colstrip's co-owners in the Pacific Northwest have been looking to get out of the coal business after voters in Washington and Oregon approved measures requiring utilities to move away from fossil fuels in favor of renewables, injecting uncertainty into the future of the plant.
NorthWestern Energy argues that Montana needs the reliable baseload power that Colstrip provides to meet growing demand, supplemented by growing wind and solar energy on the grid.
On Tuesday, Montana leaders praised the move.
“Today’s announcement is yet another step in securing a strong future for Montana-made energy,” Montana Gov, Greg Gianforte said in a statement provided by NorthWestern Energy. “Working with our partners, we've defended our all-of-the-above energy strategy to increase access to affordable, reliable energy for all Montana consumers. I thank NorthWestern for their continued investment in our state and in the community of Colstrip.”
