Myths or Facts? Understand The Facts Behind the Colstrip Power Plant

You've Heard the Myths

Get the facts about this important piece of Montana’s energy future.

NorthWestern Energy is responsible for providing reliable, affordable energy service to Montana communities 24 hours a day, seven days a week. By securing majority ownership in the Colstrip Power Plant, we are taking an important step to keep energy dependable and costs reasonable for Montana families and businesses—especially during harsh weather when energy demand is high.

This expanded ownership will secure the future of this vital resource for Montana and ensure that the Colstrip Power Plant can continue to serve a vital need for our state. 

 

Myth:

Other Colstrip Power Plant owners are leaving because wind and solar energy and battery storage is cheaper.

 

Fact:

Out-of-state owners (Avista, Puget Sound Energy) must exit the Colstrip Power Plant due to Washington state law — not because of cost. Their departure gives NorthWestern Energy the chance to secure reliable, affordable, on-demand energy for our customers at no acquisition (or upfront) cost, increasing ownership to 55% and ensuring Montanans’ energy needs are prioritized.

 

Myth:

NorthWestern Energy is stuck in the past, relying on fossil fuels.

 

Fact:

NorthWestern Energy’s Montana portfolio is among the cleanest in the U.S., with more than 58% wind, solar, and hydro generation. The Colstrip Power Plant provides on demand generation in all weather, including when the wind isn’t blowing and the sun isn’t shining.

 

Myth:

The Colstrip Plant is old, worn out, and unreliable.

 

Fact:

In the last decade, the Colstrip Power Plant has been available more than 90% of the time when NorthWestern Energy needed its generation for our Montana customers. It provides dependable, on-demand power in all weather conditions.

 

Myth:

New wind and solar farms will lower Montanans’ energy bills.

 

Fact:

Wind and solar generation has low operating costs, but its construction and land requirements are very expensive. Building enough renewable energy generation and the ability to store it to match the Colstrip Power Plant’s on-demand reliability would cost at least hundreds of millions of dollars.

 

Myth:

Montana’s energy needs can be met with existing generation.

 

Fact:

Montana has relied too heavily on out-of-state energy, which can be expensive and unavailable when demand is highest. Owning more of the Colstrip Power Plant means that Montana has reliable, affordable power—especially when demand is high and the weather is extreme. This protects our customers from price spikes and supply shortages.

 

Myth:

NorthWestern Energy’s acquisition of additional shares of the Colstrip Power Plant benefits the company’s shareholders, not Montana customers.

 

Fact:

If the Colstrip Power Plant were to close before replacement generation resources are in place, Montanans’ energy service reliability and affordability would be jeopardized. This acquisition, at no cost, ensures Montana has the energy it needs and safeguards Montana’s energy future. 

 

Myth:

Setting up a subsidiary for the Puget Sound Energy share of the Colstrip Power Plant by NorthWestern Energy is a violation of Montana law.

 

Fact:

NorthWestern Energy is acquiring Avista’s share of the Colstrip Power Plant, which is adequate to serve our Montana customers’ energy demand today. 

Generation from the Puget Sound Energy share of the Colstrip Plant is not needed right now to meet our Montana customers’ energy demand. That’s why we’ve ensured that the costs to operate and maintain this share will not be included in Montana customer rates until it is needed to serve them.

This transaction is specifically structured to protect our Montana customers and fully complies with state law and regulatory requirements.

 

Myth:

NorthWestern Energy will sell the generation from the Puget Sound Energy share of the Colstrip Power Plant, but Montana customers’ rates will pay for its operation and maintenance costs.

 

Fact:

The Montana Public Service Commission requires that the only costs in our customers’ rates are costs for the resources to provide them with energy service. 

The Puget Sound Energy share of the Colstrip Power Plant is being acquired by a subsidiary of our parent company, NorthWestern Energy Group, Inc. This means our Montana customers will not pay for costs related to that share unless and until it is needed to serve them.  

 

Myth:

It’s unprecedented for a regulated utility and an unregulated subsidiary of a holding company to own the same asset.

 

Fact:

Colstrip’s Montana ownership structure has included both regulated and unregulated shares at the direction of the Montana PSC.

 

Reliability First, Opportunity Ahead

Colstrip in the winter

Reliability First, Opportunity Ahead

Our priority is reliable, affordable energy for Montana families and businesses. We’re working collaboratively with stakeholders on a plan that supports economic development while protecting the interests of all Montanans. Together, we are building an energy strategy that strengthens our communities and secures long-term prosperity.
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Reliability First, Opportunity Ahead

Date: Dec 5, 2025
Type: News
Our priority is reliable, affordable energy for Montana families and businesses. We’re working collaboratively with stakeholders on a plan that supports economic development while protecting the interests of all Montanans. Together, we are building an energy strategy that strengthens our communities and secures long-term prosperity. This is more than an energy transaction. It’s a promise to Montana. By securing the Colstrip Plant’s capacity today, we’re safeguarding reliability during the harshest weather—and creating space for tomorrow’s opportunities. Reliability comes first. And with this acquisition, Montana can move forward with confidence -- toward an energy future that is both secure and prosperous.

Relief for Colstrip Plant supports reliable energy service for Montanans

Date: Apr 16, 2025
Type: News
Colstrip Plant owners NorthWestern Energy and Talen Energy express their gratitude to Montana’s Governor Greg Gianforte, U.S. Senators Steve Daines and Tim Sheehy, U.S. Representatives Ryan Zinke and Troy Downing, U.S. Environmental Protection Agency Administrator Lee Zeldin and the federal administration for the proclamation granting two years of relief from a new Environmental Protection Agency rule. This relief is crucial for the future of Montana’s power generation resource, which ensures reliable energy service in all weather conditions.

NorthWestern Energy announces agreement to acquire Puget Sound Energy’s share of Colstrip Plant

Date: Jul 30, 2024
Type: News
Category: Investors
Effective Jan. 1, 2026, NorthWestern Energy will acquire, at no cost, Puget Sound Energy’s 370 megawatt share of the Colstrip Plant