by Nick Fitzmaurice
Montana law requires monopoly electric utilities such as NorthWestern Energy to prepare and submit an Integrated Resource Plan (IRP) to the Public Service Commission (PSC) at least every three years. IRPs detail how utilities plan to supply reliable and affordable electricity to their customers over the coming 20 years. Engaging in the development of the IRP is incredibly important as NorthWestern usually tailors these plans to support its intent to invest in the most expensive and polluting power plants. Investing in expensive fossil fuel plants such as the Colstrip plant and the Yellowstone County Generating Station (YCGS) increases NorthWestern’s revenues on the backs of ratepayers. After NorthWestern submitted its last IRP in 2023, nearly 500 people from across Montana showed up at the PSC’s public meetings to decry its inadequacies. Many of these comments were reflected in PSC staff’s analysis, even if some were cut from the PSC’s final analysis. The opportunity for robust public engagement in NorthWestern’s current IRP is now upon us.
Join MEIC’s webinar on Jan. 22 to learn about NorthWestern’s draft IRP.
NorthWestern has been developing its current IRP since late 2023 and intends to have a draft completed by the end of this year. As of this writing, the utility was planning to host public presentations of its draft IRP in Bozeman, Helena, Missoula, and Great Falls on undetermined dates in January and February after publicly unveiling the draft IRP in Butte on January 16, 2026. However, NorthWestern has been shifting around its IRP timeline as it seeks various regulatory approvals to expand its ownership in the Colstrip plant (see related article on pg. 8) and to merge with Black Hills Energy. NorthWestern proposes to file its IRP with the PSC on April 28, 2026. Once the IRP is filed, the PSC will host at least two public meetings.
MEIC has been engaged in the development of NorthWestern’s current IRP from the start. In 2024, MEIC persuaded the PSC to send a letter to NorthWestern regarding concerns about the utility’s compliance with Montana statutes and the Commission’s administrative rules for transparency and public participation in IRP development. Although the process is extremely opaque, MEIC continues to monitor NorthWestern’s technical advisory committee and is a member of NorthWestern’s IRP Stakeholder Working Group.
MEIC’s primary issues regarding NorthWestern’s IRP include:
- Modeling participation in energy markets
- Integrating electric transmission planning
- Accurately modeling energy storage by itself and in combination with clean energy resources
- Assumptions around generator capacity factors and resource reliability
- Modeling the true costs of the Colstrip plant and planning for its retirement
- Assessing the climate impacts of its power plants and reaching net zero emissions
- Fairly representing energy resources for selection in IRP modeling
- Creating a more transparent and robust IRP development process
A detailed summary of our concerns can be found on MEIC’s website.
When a draft IRP is made available to the public, MEIC will review it thoroughly as we call on our members and supporters to show up to NorthWestern’s and the PSC’s public IRP meetings.
This article was published in the December 2025 issue of Down To Earth.
