Groups File Complaint to Stop NorthWestern Energy from Shifting Data Center Costs to Residential Customers

Community, conservation and Indigenous-led organizations yesterday filed a complaint before the Montana Public Service Commission challenging NorthWestern Energy’s intent to provide electricity supply service to large load data centers without first proving that it will not adversely impact existing ratepayers. The groups, represented by Earthjustice, warn that NorthWestern’s data center agreements could increase costs for residential ratepayers and deepen the state’s reliance on expensive fossil fuels.

QUOTES FROM PETITIONERS AVAILABLE HERE: https://earthjustice.org/document/quote-sheet-for-montana-psc-data-center-complaint

The complaint targets NorthWestern’s efforts to provide electricity to data centers without the opportunity for public input or the required approval from the PSC. Montana law requires NorthWestern to first demonstrate that providing service to new large load customers will not adversely impact existing ratepayers over the long term. In September, NorthWestern informed the PSC that it does not intend to disclose information on impacts to existing customers before it begins providing service to data centers as early as January 2026.

The groups have asked the PSC to create a separate customer class, which would force new data center customers to pay the costs associated with their electricity supply rather than shifting the cost to residential ratepayers. The groups have also asked the PSC to require NorthWestern to comply with ratepayer-protective rules, in the form of a mandatory tariff, when meeting data center demand. The groups argue that granting both of these requests is necessary to protect NorthWestern’s residential customers because of the extremely large loads contemplated by data centers.

NorthWestern has entered into letters of intent to provide as much as 1,400 megawatts of electricity supply to three data center developers in Montana, approximately double the utility’s current average retail daily load. To serve this extreme demand, NorthWestern would need to make transmission upgrades and likely obtain new sources of electricity generation, which would likely lead to further increases in utility bills for NorthWestern’s other customers.

NorthWestern has filed a motion for a protective order for its letters of intent with data centers after the commission requested additional information on the customers mentioned in the utility company’s press releases. In October, the plaintiffs sent a letter to the PSC noting the lack of transparency around NorthWestern’s data center plans and urging a denial of the protective order.

Earthjustice represents 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, Montana Public Interest Research Group, and NW Energy Coalition.