Effective Jan. 1, 2026, NorthWestern Energy will acquire, at no cost, Puget Sound Energy’s 370-megawatt share and Avista's 222-megawatt share of the Colstrip Plant.
Following these acquisitions, NorthWestern Energy will own 55% of the Colstrip Plant. Majority ownership allows NorthWestern Energy to effectively guide investments in operation and maintenance of the Colstrip Plant, ensuring the plant continues to provide on-demand, 24/7 cost-effective generation for our Montana customers until viable, equivalent, carbon-free energy resources are commercially available.
Brian Bird
NorthWestern Energy President and CEO
The Colstrip Plant is a dependable bridge to a cleaner energy future, which could ultimately include new lower- or no-carbon emitting resources such as gas-fired generation, small modular nuclear reactors, long-duration storage or other technologies, which we believe could be located in the Colstrip area. But this will take time and we will not sacrifice service reliability during the transition.
Other states require a transition away from coal resources at a pace faster than is feasible in Montana. This no-cost acquisition allows our customers to transition to a cleaner energy future at a pace that works for Montanans.
Montana has considerable low-cost wind and solar generation on our system today, but that generation is variable. The Colstrip Plant’s generation provides power for our Montana customers when the wind isn’t blowing, and the sun isn’t shining at costs that are typically much less than the cost of purchasing energy on the market.
When the sun is shining and the wind is blowing, we can reduce the amount of power being generated by the Colstrip Plant.
"This announcement is great news for Montana citizens and businesses that rely upon NorthWestern Energy for reliable and low-cost power. NorthWestern Energy is now in the driver’s seat, securing Montana’s energy future"
“We want people to invest in Montana who want to be in Montana, and that happened here with NorthWestern Energy. This development will better ensure Colstrip remains in service throughout its full, useful life, and it’s encouraging for Montanans who rely on the reliable, affordable electricity Colstrip generates.”
“Colstrip—the power plant, the town, and most importantly the people—are crucial to Montana’s future. Last night’s announcement is the best news coming out of Colstrip in many years. We are excited and encouraged about the future of Colstrip, its people, and Montana energy production.”
- Senate President Jason Ellsworth, President Pro Tempore Ken Bogner, Majority Leader Steve Fitzpatrick, House Speaker Matt Regier, Speaker Pro Tempore Rhonda Knudsen, and Majority Leader Sue Vinton
“I’m encouraged by the news of NorthWestern’s expanded stake in Colstrip’s power plant. This partnership will provide stability for the town of Colstrip and the state of Montana, while maintaining our commitment to affordable, reliable energy. Not only will it create jobs and lower energy costs for Montanans, but it's a step toward restoring America's energy dominance.”
“Very positive news about the future of Colstrip. Tens of thousands of Montana households rely on the affordable and reliable power that only Colstrip can provide. Glad to see we can count on Made in Montana energy through the decade.”
"Affordable, reliable electricity is a cornerstone to economic growth. Northwestern Energy's acquisition of a larger share of Colstrip allows us to continue pursuing an 'all of the above' energy strategy while lessening dependence on commercial markets, which drive up rates for all. This announcement is good news for Colstrip, Montana, and the entire business community."
At NorthWestern Energy, our goal is to provide our customers reliable energy at the lowest long-term cost. We do this through a balanced mix of safe, reliable, affordable and clean energy. Our electric portfolio is built on the carbon-free hydro system, along with wind, coal, gas and solar.
Over time, the natural gas plants and other thermal generation on our system will be used less as new cleaner, cost‑effective resources are available.For more information about the project, please contact:
