Data Centers/Northwestern Energy: Environmental/Community Groups File Montana Public Service Commission Complaint Challenging Electric Supply Service

Montana Public Interest Research Group and 8 other organizations filed a November 17th Complaint before the Public Service Commission of the State of Montana (“Commission”) against NorthWestern Corporation d/b/a NorthWestern Energy (“NW”) alleging that its practices and acts with respect to the provision of electricity supply service to data center developers are unreasonable, insufficient, and contrary to Montana law.

The other organizations joining the Complaint include:

• Big Sky 55+
• Butte Watchdogs for Social and Environmental Justice
• Climate Smart Missoula
• Golden Triangle Resource Council
• Helena Interfaith Climate Advocates
• Honor the Earth
• Montana Environmental Information Center
• NW Energy Coalition

(Collectively, “MPIRG”).

MPIRG states that NW:

• Intends to provide 1,400 megawatts of electricity supply service to three data center developers in Montana.
• Current average daily retail load is approximately 759 megawatts.
• NW has stated that it will provide electricity supply service to the first of these data centers beginning in January 2026.

The Complaint further alleges that NW has stated an intent to provide electricity supply service data centers without complying with Mont. Code Ann. § 69-8- 201(1). This state statutory section is stated to prohibit a public utility from providing electricity supply service to retail customers with an average monthly demand load of equal to or greater than five megawatts unless the Commission first determines that the provision of such service will not adversely impact the utility’s other customers over the long term.

The Complaint alleges that NW’s practices and acts with respect to the provision of electricity supply service to data center developers are insufficient because:

• Refusal to allow the Commission to determine whether provision of such service will adversely impact the utility’s other customers over the long term.
• Abrogates the public’s right to meaningfully participate in the process by which the Commission makes that finding.
• Unreasonable given existing capacity and transmission system in Montana.

MPIRG requests that the Commission inform NW that it cannot provide electricity supply service to large load customers until the Commission determines that the provision of such service will not adversely impact the utility’s other customers over the long term.

The organizations request that the Commission initiate a contested case proceeding with an evidentiary hearing to evaluate and further investigate the issues outlined in this Complaint and issue a procedural order to determine the schedule for expert testimony.

The Complaint further requests that the Commission:

1. Create a separate customer class for data centers;
2. Use its investigatory authorities to address any evidentiary issues in cost allocation between distinct customer classes; and
3. Impose mandatory tariff terms for large load data centers to protect existing ratepayers from cost shifting.

A copy of the Complaint can be found here.