The Montana Public Service Commission voted 3-1 on Tuesday to return NorthWestern Energy’s 20-year resource plan to the utility, citing five shortcomings identified by PSC staff and directing the company to make corrections within 30 days or request an extension.

What the Commission Found

PSC staff identified five deficiencies in the integrated resource plan, which NorthWestern Energy is required to update every three years. Among the most notable gaps: the plan fails to adequately account for data centers as a growing driver of electricity demand and relies on short-term compliance requirements rather than a thorough long-term analysis of future energy needs.

Commissioners also raised concerns that NorthWestern’s forecasting models may be structured in ways that steer outcomes toward more costly resources, such as new power plant construction. Similar modeling transparency issues had been flagged during review of the utility’s 2023 resource plan, making the recurrence a point of emphasis for commissioners.

Despite the vote to send the plan back, PSC Vice Chair Jennifer Fielder framed the decision as routine oversight rather than an outright rejection. “Returning the plan isn’t necessarily a wholesale rejection of the plan. It’s basically a quality control step,” Fielder said, as first reported by the Daily Montanan.

Fielder also explained why incomplete analysis at this stage carries real consequences for ratepayers and grid reliability. “Having incomplete analysis at this point in an IRP actually increases the chance that there could be overbuilding, which would result in higher rates, or under-preparing, which results in those reliability risks,” she told the Daily Montanan.

A Mixed Picture on Progress

The commission’s action does not mean NorthWestern’s planning work was entirely without merit. An independent consultant, GDS Associates — hired at a cost of up to $260,000 — concluded that the 2026 plan represented a meaningful improvement over the 2023 version. Still, the consultant’s positive assessment was not enough to move the plan past PSC staff’s identified deficiencies.

The shortcomings flagged this cycle — particularly around data center load growth and long-range analytical completeness — reflect broader pressures facing utilities across the West as artificial intelligence infrastructure and large-scale computing facilities expand their footprint and electricity consumption.

The Vote and Who Dissented

Commissioner Annie Bukacek cast the lone dissenting vote against returning the plan. Commissioner Brad Molnar was suspended at the time of the vote, leaving four commissioners to decide the matter. The 3-1 outcome gives NorthWestern a clear mandate to address the identified gaps, but the commission stopped well short of blocking the utility’s planning process altogether.

NorthWestern now has 30 days to submit corrections or formally request more time. The revised plan will need to satisfy PSC staff on the five points of concern before moving forward in the regulatory process.

What Comes Next

The ball is now in NorthWestern Energy’s court. The utility will need to revisit its demand forecasting methodology, strengthen its analysis of large new electricity loads like data centers, and provide greater transparency in how its models evaluate resource options. Whether NorthWestern seeks an extension will likely depend on the scope of revisions required to address all five deficiencies.

The outcome has practical stakes for Montana ratepayers. Integrated resource plans guide a utility’s long-term investment decisions — which generation sources to build or contract, how to plan for reliability, and ultimately what those choices cost customers on their monthly bills. Flawed planning assumptions, as Fielder noted, can lead to either expensive overbuilding or gaps in supply that threaten grid stability.

The PSC’s scrutiny of NorthWestern’s planning process is part of a wider set of energy policy questions facing Montana, as state and federal officials weigh decisions about resource development and land management that will shape the region’s long-term energy landscape.