The Montana Public Service Commission released three long-redacted documents Monday showing the scale of data center deals NorthWestern Energy has been negotiating — a disclosure that came after months of pressure from public interest groups who had been trying to see the materials.

What this means for you
MontanaMontana ratepayers and regulators now have a clearer picture of how much power — potentially 1,650 megawatts in total across three developers — NorthWestern Energy was being asked to deliver for data center projects. No binding service agreements are in place, and a proposed tariff rule meant to shield existing customers from new costs is still pending before the PSC.
Silver Bow CountyThe Butte Montana Connections Site fell through in May, and no replacement Butte-Silver Bow location for Sabey Data Centers has been identified, leaving the Mining City without a confirmed data center project.
Watch nextThe PSC's review of NorthWestern's proposed tariff rule — which would determine how data center infrastructure costs are allocated — is the next formal regulatory step to watch; no hearing date was specified in available source material.

Until now, the PSC had shielded the contents of the letters of intent from public view, blacking out entire pages at a time. After NorthWestern told the commission on July 31 that it mostly no longer had reason to keep the agreements secret, the documents were released with just one word remaining redacted across all three.

NorthWestern attorney Sarah Norcott wrote to the commission that two of the three developers — Quantica Infrastructure and Atlas Power Group — had confirmed their letters of intent were no longer confidential. "Subsequent developments with these potential customers have also diminished the economic value derived from the confidentiality of these LOIs," Norcott wrote.

The third developer, Sabey Data Centers, still wanted one detail kept private: the location of a second potential site. The revised documents show Sabey was considering two sites, each capable of receiving up to 250 megawatts — a combined 500 megawatts. One of those sites was the proposed Butte Montana Connections Site, which fell apart in May after REC Silicon exercised a right of first refusal over the land. The second location remains blacked out.

Butte-Silver Bow Chief Executive JP Gallagher said in an Aug. 5 statement to Lee Montana newspapers that another Butte site has not been identified. "Sabey had indicated they were still evaluating other potential sites in Southwest Montana, but we have not identified another location within Butte-Silver Bow that they've expressed interest in since the termination in late May," Gallagher wrote.

The Quantica letter, entered into July 1, 2025, shows the developer planned to draw up to 1,000 megawatts from NorthWestern substations north of Billings. The Atlas Power letter, dated Dec. 9, 2024, shows that company planned to use up to 150 megawatts from the utility south of Butte.

NorthWestern Energy spokesperson Jo Dee Black cautioned that the letters of intent are not binding agreements and may not reflect current conditions. The utility is conducting studies to determine how data centers' power needs and costs can be met. Those studies would feed into the negotiation of formal Electric Service Agreements, which would then go before the PSC for review.

No Electric Service Agreements are currently active, Black said.

The disclosures come as NorthWestern moves forward with a proposed tariff rule designed to prevent existing residential and business customers from bearing new infrastructure costs tied to large power users like data centers. The PSC has not yet acted on that tariff proposal.