PSC Withdraws FERC Intervention, Opens State Investigation of NWE Transactions

PSC Withdraws FERC Intervention and Opens State Investigation of NWE’s Colstrip Transactions

FOR IMMEDIATE RELEASE

DECEMBER 12, 2025

PSCMedia@mt.gov

406-444-6199

HELENA, Montana — The Montana Public Service Commission (PSC) announced today that it has withdrawn its recent intervention at the Federal Energy Regulatory Commission (FERC) related to NorthWestern Energy’s proposed acquisition of Puget Sound Energy's share in the Colstrip power plant. The PSC plans to open its own state-level investigation into the transaction.

The PSC initially intervened at FERC on December 3, 2025 to obtain clarity regarding newly identified NorthWestern Energy activity and to ensure accountability for state regulatory jurisdiction and oversight. Following additional fact-finding and analysis, the Commission determined that its concerns could be more appropriately addressed through the state regulatory process. This review included confirmation that energy from Colstrip will remain available to meet the needs of Montana retail customers, subject to PSC approval.

“Given extremely limited information, tight timeframes, and uncertainty about NorthWestern’s actions, the PSC moved quickly to intervene in FERC Docket ER26-129,” said Commission Vice President Jennifer Fielder. “I supported that action out of concern that we did not fully understand the transaction and that adequate supplies of least-cost power for Montana retail customers could be at risk. Now that we have had the opportunity to analyze the matter more carefully, I believe these concerns have been—or can be—addressed through the state regulatory process.”

If completed by December 31, Northwestern Energy’s acquisition of Puget’s Colstrip share means the resource will be available to support the long-term energy needs of Montana retail customers in the future. The Commission emphasized that withdrawing from the FERC intervention is a procedural decision only and does not reflect any substantive judgment on the merits of the transaction. These merits will be evaluated through a separate state investigation addressing matters within the Commission’s jurisdiction. FERC is expected to decide on Northwestern’s filing within the next two weeks.

“We will thoroughly investigate at the state level as appropriate,” Commission President Jeff Welborn stated. “We remain committed to acting within our statutory authority, ensuring transparency, protecting Montana ratepayers, and maintaining the reliability of essential utility services.”

The PSC highlighted that today’s action neither endorses nor opposes the proposed acquisition. The Commission also stressed that the withdrawal does not prejudge any future matters that may come before it in a formal proceeding. The PSC’s ability to exercise its statutory oversight and the full range of its investigative authority is unaffected by the withdrawal. These actions reflect balanced, responsible oversight and the Commission’s ongoing commitment to Montana’s consumers and regulatory integrity.

The Commission regulates private investor-owned natural gas, electric, telephone, water, and sewer companies, certain motor carriers, and oversees natural gas pipeline safety and intrastate railroad safety. The Commission works to ensure that Montanans receive safe and reliable service from regulated public utilities while paying reasonable rates. For more information, visit psc.mt.gov or contact the Commission at 1-800-646-6150.  Follow the Commission at x.com/MT_PSC or visit facebook.com/MontanaPSC.