The Montana Public Service Commission has released previously confidential documents outlining NorthWestern Energy's letters of intent with three data center developers — giving the public its first real look at the scale of power demand those projects could place on the state's largest utility.
The documents, released Monday, had previously been so heavily redacted that entire pages were blacked out. After NorthWestern sent the PSC a letter on July 31 waiving most of its confidentiality claims, only a single word remained redacted across the three agreements. Multiple public interest groups had pressed the commission for months to make the materials available.
NorthWestern attorney Sarah Norcott told the commission that two of the three developers — Quantica Infrastructure and Atlas Power Group — had indicated the 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, using the acronym for letters of intent.
Together, the three agreements sketch out an ambitious — if still tentative — picture of data center development across Montana:
**Quantica Infrastructure** holds a letter of intent, dated July 1, 2025, to draw up to 1,000 megawatts from NorthWestern substations north of Billings. That would be the largest single load of the three.
**Atlas Power Group** signed a letter dated Dec. 9, 2024, for up to 150 megawatts from NorthWestern infrastructure south of Butte.
**Sabey Data Centers** had been evaluating two sites, each capable of receiving up to 250 megawatts — a combined 500 megawatts. One was the proposed Butte Montana Connections Site, but that project collapsed in May after REC Silicon exercised a right of first refusal over the land. The second site remains redacted at Sabey's request. Norcott stated the company still considers that location commercially sensitive.
Butte-Silver Bow Chief Executive JP Gallagher, in an Aug. 5 statement to Lee Montana newspapers, said the county has not identified another site within Butte-Silver Bow where Sabey has expressed interest since the May termination. "Sabey had indicated they were still evaluating other potential sites in Southwest Montana," Gallagher wrote, leaving open the possibility the undisclosed site is elsewhere in the region.
NorthWestern Energy spokesperson Jo Dee Black said the utility is currently conducting studies to determine how data center power needs and associated costs can be met. Those studies would feed into negotiations for formal Electric Service Agreements, which would then go to the PSC for review — a process outlined in NorthWestern's proposed tariff rule, which is designed to prevent existing customers from being saddled with costs tied to new large-load customers. Black said no such agreements are currently active.
The letters of intent themselves are not binding service agreements, and NorthWestern has cautioned that developments since each letter was signed — particularly for the older Atlas and Sabey agreements — mean the documents may not fully reflect current circumstances.
Still, NorthWestern CEO Brian Bird said during an earnings call last week that he expects formal agreements to be reached with Quantica by the end of the year.