Public Service Commission says NorthWestern’s energy plan ‘deficient’
The Montana Public Service Commission (PSC) voted 3-1 to return NorthWestern Energy's 20-year energy plan, citing five deficiencies. The plan, required every three years, must be revised to meet minimum state requirements. Concerns include transparency about data centers, long-term energy needs, and potential cost impacts on customers. NorthWestern has 30 days to address the issues or request an extension. According to the company, the plan reflects extensive analysis and stakeholder engagement.
How this was made
The 30-second read
Why it matters
The Montana Public Service Commission sent the 2026 IRP back for revisions after staff identified five shortcomings, including insufficient transparency on how data centers are incorporated into load forecasts and a lack of comprehensive long-term analysis.
Market read
Traders in regulated utilities may reprice the risk that IRP-related capex and rate impacts face delays or changes due to commission-required revisions.
What to watch
The article notes Commissioner Molnar’s suspension and that only four commissioners voted, which could affect perceived finality; also, the consultant’s findings are not the final commission decision on costs or resource selection.
Background
Every three years, NorthWestern Energy must file an Integrated Resource Plan (IRP) assessing future power needs and resource options for Montana customers.
Ticker impact
Montana PSC returned NorthWestern Energy’s 2026 integrated resource plan for revisions after finding five deficiencies, including data-center load transparency and long-term forecasting gaps.
Near-term downside bias for NWE on regulatory overhang; magnitude likely limited unless the revisions materially change capex or rate outcomes.
The PSC cannot outright reject the plan but can require corrections within 30 days, and the staff report flags repeat issues from the 2023 plan plus potential bias toward more expensive resources.
Market effects
Highlights heightened regulatory scrutiny of utility integrated resource plans, especially around data-center load forecasting and model transparency.
Montana ratepayer and reliability debates may influence how other state commissions evaluate similar IRPs.
Limited direct global impact, but reinforces a broader US trend of regulators demanding more transparent long-term planning.
Counterpoint
Because the PSC framed the return as a quality-control step and not a wholesale rejection, NWE may still reach approval after revisions without major economic damage.
Key entities
- companyNorthWestern Energy
Utility whose 2026 Montana IRP was returned for deficiencies, with specific concerns about data-center forecasting and long-term modeling.
- regulatorMontana Public Service Commission
Commission that reviewed the IRP, voted 3-1 to return it for revisions, and set a 30-day correction timeline.
- consultantGDS Associates
Consultant whose report said the 2026 plan was a step forward but still fell short on multiple requirements, including data-center treatment.
