A proposed NorthWestern Energy tariff for data centers has drawn an unusually broad coalition of interveners to the Montana Public Service Commission, with the Gianforte administration, conservation organizations, senior citizen advocates, industrial customers, and municipal governments all seeking participation in the rate-setting proceeding.

What’s at Stake

NorthWestern Energy filed the data center tariff proposal with the PSC in March. The proceeding has since attracted widespread attention because of concerns that serving large, power-hungry data center customers could drive up electricity costs for existing residential and business ratepayers across Montana.

The deadline to request participation passed last week, and a hearing date has not yet been set. The Montana Consumer Counsel, which represents residential and small business ratepayers in utility proceedings, has confirmed it will participate.

Montana’s average household energy burden already ranks among the highest in the West — a figure that predates NorthWestern’s rate increases in 2023 and 2025, according to the City of Missoula’s petition to intervene.

The Gianforte Administration’s Position

Governor Greg Gianforte’s office is seeking intervention through the Department of Environmental Quality, which holds regulatory authority over large energy projects under the Montana Major Facilities Siting Act. The administration’s stated goal is to ensure that data centers bring high-paying jobs to Montana without forcing existing customers to subsidize the cost of new infrastructure built to serve them.

The DEQ’s involvement signals that the administration sees the issue as straddling both economic development and consumer protection — a balance the governor has emphasized across energy and industrial policy.

Municipal and Community Concerns

The City of Missoula is seeking intervention with a focus on affordability protections, arguing that data centers should not become a barrier to access for ordinary residents. The city’s petition warned that electricity access is a fundamental need, and it cited the already-elevated energy burden Montana households carry.

Helena Interfaith Climate Advocates echoed that concern, arguing that “access to affordable electricity is a basic need that needs to be protected.”

Community groups went further, arguing that a tariff adjustment alone is insufficient and that data centers should be classified as a separate customer class entirely — a distinction that could provide cleaner cost accounting and prevent cross-subsidization.

The Butte Watchdogs for Social and Environmental Justice raised a different concern: transparency. The group cited redacted documents in the data center proceeding, calling the lack of public disclosure troubling given the scale of the infrastructure decisions involved.

Missoula County, the City of Missoula, Bozeman, and NorthWestern Energy are separately developing a Green Power Program, underscoring that local governments are not uniformly opposed to large energy consumers — but want appropriate safeguards built in before data centers are welcomed onto the grid.

Industrial and Utility Interests

The Large Customer Group, a coalition of industrial power users, is seeking assurances that any new tariff structure will treat all large customers fairly and remain consistent with existing Montana law. Industrial customers typically benefit from volume pricing and are wary of arrangements that might disadvantage them relative to a newly favored customer class.

The Northwest and Intermountain Power Producers Coalition is pushing for a competitive electric supply market, arguing that NorthWestern’s proposed tariff design would give the utility more control over data center power arrangements than would be appropriate under a well-functioning regulatory framework. Conservation watchdog groups raised a parallel concern, arguing the proposal tilts oversight authority away from the PSC and toward the utility itself.

What Comes Next

The PSC has indicated it will work to ensure that any approved data center service arrangement does not harm other customers over the long term. With the intervention window now closed, the commission will review the petitions and determine which parties have standing to participate before scheduling a formal hearing.

The data center question is part of a broader conversation about Montana’s energy future. As drought grips 85 percent of the state and water and power reliability come under pressure, decisions about who gets priority access to the grid — and at what cost — carry significant consequences for both rural communities and growing urban centers.

The outcome of this proceeding could shape how Montana handles a wave of data center interest in the Mountain West for years to come.