MT — Power Infrastructure Updated 2026-07-17

Montana

WECC Queue Bottlenecks Transmission Constraints

1. Grid operator and market structure

  • NorthWestern Energy remains the central utility actor for Montana data-center load growth. Montana DEQ’s data-center FAQ states that data centers served by a regulated utility take service under Public Service Commission-approved tariffs and that a new NorthWestern customer over 5 MW must demonstrate to the PSC that service will not adversely affect other customers under MCA 69-8-201. Montana DEQ Data Center FAQ, 2026-01
  • NorthWestern’s 2026 Montana Integrated Resource Plan treats data centers as the most significant emerging load uncertainty, not as part of the base forecast. The IRP says data centers are a new topic in the long-term load forecast, excludes potential data-center load from the base forecast, and models separate sensitivities for 150 MW, 650 MW, and 1,160 MW of incremental data-center load. NorthWestern Energy 2026 Montana IRP, 2026-05
  • NorthWestern reported three data-center letters of intent or similar early commitments in 2024-2025, while advocates alleged broader developer interest. The IRP says NorthWestern entered letters of intent with three data centers pursuing Montana development, and February 2026 reporting says advocacy groups told regulators that NorthWestern was in talks with at least 11 additional entities, with some in Montana. NorthWestern Energy 2026 Montana IRP, 2026-05; Daily Montanan, 2026-02-23
  • The state’s July energy-policy work remains advisory. The Governor’s Energy Task Force draft report recommends clarifying how utilities and independent power producers may serve loads above 5 MW, how customers may switch suppliers without leaving stranded utility costs, and what counts as self-generation. The final report is due later in 2026, so these are not yet statutes, PSC rules, or approved tariffs. Montana Department of Environmental Quality, 2026-07-08

2. Interconnection queue

  • NorthWestern’s generation interconnection queue has been closed since June 10, 2024 while the utility transitions to a cluster-study process under FERC Order 2023. The 2026 IRP also gives 2026-dollar generic estimates for a 230 kV point of interconnection and network upgrades, underscoring that large new loads and generation additions can require material transmission studies and upgrade costs. NorthWestern Energy 2026 Montana IRP, 2026-05
  • Quantica materially expanded the interconnection picture in May 2026. Quantica filed interconnection applications with NorthWestern for additional generation to support its proposed 1,100 MW Big Sky Campus in Yellowstone County; the applications cover up to 7,235 MW of maximum additional capacity across renewable and firming generation plus battery storage, and Quantica says it will pay for the additional power capacity rather than shift that cost to NorthWestern ratepayers. Quantica Infrastructure, 2026-05-20
  • A separate cooperative-served expansion surfaced in June. Hyperscale Data said Lower Yellowstone Rural Electric Cooperative issued BNI Montana a conditional “will serve” letter for up to 125 MW of additional power at one of two leased sites that each can currently operate at about 10 MW. The letter is not an energized interconnection: the company says it requires further studies, transmission and distribution upgrades, regulatory approvals, financing, and a utility agreement, with one necessary transmission line then projected for 2031. Hyperscale Data release via Nasdaq, 2026-06-24
  • The Bonner/Krambu load is no longer an active 7-29 MW interconnection prospect. The property owner withdrew his signature on July 6, and Missoula County says the project will not move forward. Missoula County Voice, accessed 2026-07-17; Inside Climate News, 2026-07-09
  • The Sabey Butte interconnection/load issue is no longer tied to the original 606-acre buy-sell agreement. Sabey terminated that agreement after REC Silicon exercised a right of first refusal, so the Butte site should not be treated as awaiting only power-contract approval even though Sabey may pursue another southwest Montana site. NBC Montana, 2026-06-01
  • Montana’s task force has flagged large-load interconnection as unfinished policy work. Its draft recommendations call for coordination with FERC on large-load interconnection, more flexible demand to reduce time-to-power, and legislation clarifying service by utilities and independent power producers; no Montana-specific final interconnection rule resulted by July 17. Montana Department of Environmental Quality, 2026-07-08

3. Ratepayer protection

  • The major 2026 PSC proceeding is NorthWestern’s Large New Load tariff application. NorthWestern filed the tariff on March 31 for bundled electric customers with new or expanded loads of 5 MW or more, including data centers; the proposal includes development agreements, studies, minimum demand and energy billing, performance assurance/collateral, termination-cost protections, curtailment provisions, and longer minimum terms for loads of 50 MW or more. NorthWestern Energy, 2026-03-31; NorthWestern Energy Large New Load Tariff Application, 2026-03-31
  • Docket 2026.04.023 remained pending on July 17, 2026. Under the proposal, loads of 50 MW or more would require PSC review and approval of an electric service agreement, while 5-49 MW customers would use the standardized tariff without case-specific agreement approval. No final PSC order had been reported by the cutoff. Montana PSC notice via Daily Inter Lake, 2026-06-10; Daily Montanan, 2026-07-14
  • Intervention broadened after the June 10 snapshot. DEQ sought intervention to advocate full cost recovery from large loads and adequate collateral for project failure, while reporting after the June 19 deadline counted nine requests to participate from consumer, environmental, industry, state, local-government, and power-market interests. Montana Governor’s Office, 2026-06-18; Montana Free Press, 2026-06-30
  • A consumer/environmental coalition asked the PSC to create a separate data-center customer class and expand public review. The coalition argues that NorthWestern’s proposed 5 MW threshold would allow 5-49 MW data-center agreements to avoid case-specific Commission review and asked for a hearing and a broader inquiry; this is an intervenor position, not a PSC ruling. Earthjustice, 2026-06-15; Daily Montanan, 2026-07-14
  • The PSC kept most data-center discovery out of NorthWestern’s separate merger case. On March 31, commissioners declined requests by Montana Farmers Union and 350 Montana to compel additional letters of intent, load forecasts, and water studies in Docket 2025.10.078, citing procedural defects and the merger case’s scope. That ruling did not decide the large-load tariff or establish that the requested information was immaterial to those other proceedings. Daily Montanan, 2026-03-31
  • The task force’s tariff recommendations are also nonbinding. Its July draft supports DEQ’s intervention and calls for a pathway for large loads that protects legacy customers, including cost allocation and stranded-cost safeguards, but leaves the tariff decision to the PSC. Montana Department of Environmental Quality, 2026-07-08
  • Montana joined the federal Ratepayer Protection Pledge, but the pledge does not itself set a Montana rate. The federal principles call for data-center operators to build, bring, or buy new generation; pay for delivery-system upgrades; accept long-term take-or-pay commitments; and use a separate rate structure. Montana reporting described Gov. Greg Gianforte’s participation as voluntary and nonbinding, so implementation still depends on the PSC case and future law. The White House, 2026-03-04; Montana Governor’s Office, 2026-07-08; Daily Montanan, 2026-07-14

4. Generation adequacy

  • NorthWestern’s 2026 IRP says the existing portfolio meets 2026 WRAP obligations but shows near-term winter capacity pressure beginning in 2027-2028. The IRP identifies a winter capacity shortfall of about 23 MW in 2027-2028, growing toward roughly 200 MW after a capacity contract expires, even before including data-center load in the base forecast. NorthWestern Energy 2026 Montana IRP, 2026-05
  • The PSC opened the IRP to public listening sessions and comments rather than approving a specific resource plan. On July 13, the Commission announced July 21 and July 23 listening sessions and a July 28 comment deadline in consolidated Dockets 2026.04.026 and 2025.05.038. The PSC notice highlights a possible winter shortage beginning in 2027 and states that the IRP does not request approval of specific resources. Montana Public Service Commission, 2026-07-13
  • The data-center sensitivities assume NorthWestern acquires 370 MW of Puget’s Colstrip share and then layers in large data-center load. Sensitivity J adds 150 MW, Sensitivity K adds 650 MW, and Sensitivity L adds 1,160 MW of data-center load at an 85% load factor; the larger cases require significant additional resources to meet capacity needs. NorthWestern Energy 2026 Montana IRP, 2026-05
  • FERC accepted the wholesale tariff for the acquired 370 MW Puget share during the update window. Its February 27 order allowed NorthWestern Colstrip 370Pu LLC to make cost-based short-term wholesale sales effective January 1; FERC left protection against improper retail cost shifts to Montana’s retail-rate jurisdiction. NorthWestern’s filing says the share’s output is contracted for wholesale sale through late 2027, so the IRP’s later use of the share in data-center sensitivities should not be confused with immediately available retail capacity. Federal Energy Regulatory Commission, 2026-02-27; NorthWestern Energy Form 10-K, 2026-02-12; Daily Montanan, 2026-03-02
  • NorthWestern’s cost modeling does not support a simple conclusion that every data center raises—or lowers—unit costs. The IRP reports lower normalized system-average cost per MWh in the 150 MW and 650 MW sensitivities and a modest increase in the 1,160 MW sensitivity, while total portfolio costs increase because more resources are added to serve more load. NorthWestern Energy 2026 Montana IRP, 2026-05
  • Generation and backup-power choices, not servers themselves, trigger many air-quality permitting issues. DEQ says server equipment does not directly emit regulated air pollutants, but backup diesel or gas generators, on-site fossil generation, and dedicated generation may require air-quality permits depending on design. Montana DEQ Data Center FAQ, 2026-01

5. Load forecasts

  • The base forecast should not be read as a forecast that all announced data centers will be served. NorthWestern excluded speculative data-center load and instead used sensitivities, while two once-public project prospects changed status during 2026: Sabey’s original Butte site ended and Bonner/Krambu was withdrawn. NorthWestern Energy 2026 Montana IRP, 2026-05; NBC Montana, 2026-06-01; Missoula County Voice, accessed 2026-07-17
  • Quantica remains the largest discrete announced load, but its generation applications are far larger than campus demand. The proposed campus is 1,100 MW, while the generation/interconnection applications describe up to 7,235 MW of maximum additional capacity across multiple resources; neither figure is an in-service load forecast. Quantica Infrastructure, 2026-05-20
  • Hyperscale Data’s 125 MW figure is also conditional rather than forecast in-service load. The disclosed site currently operates at about 10 MW, and the company gave no completion schedule for the expansion beyond noting that one needed transmission line was then targeted for 2031. Hyperscale Data release via Nasdaq, 2026-06-24

6. Behind-the-meter generation and water

  • Quantica proposes a mixed supply strategy rather than reliance on a single utility resource. Its May filing describes renewable generation, firming resources, battery storage, direct transmission investment, and an intent to fund added power capacity. These remain developer plans subject to interconnection and other approvals. Quantica Infrastructure, 2026-05-20
  • HB 424 made on-site generation and storage more important to Montana’s data-center tax framework. The enacted language added qualifying electrical generation and storage property associated with a qualified data center to Class 17 treatment and addressed power sold to qualified data centers at cost of production. Montana Legislature, 2025-05-13
  • Hardin’s Big Horn/Beowulf facility is the clearest operating example of direct or dedicated supply in the current DEQ list. DEQ lists the 100 MW Hardin facility with Hardin Generating Station as its energy supplier. Montana DEQ Data Center FAQ, 2026-01
  • Water and wastewater permitting depend heavily on cooling configuration. DEQ distinguishes high-water evaporative cooling from closed-loop and geothermal systems, says DNRC approval is needed for water supply unless a project uses an existing system with water rights, and explains that wastewater or underground-injection requirements vary by discharge pathway. Montana DEQ Data Center FAQ, 2026-01

7. Transmission constraints

  • Transmission remains a limiting factor for both loads and the resources intended to serve them. NorthWestern’s IRP discusses the closed generation interconnection queue, generic 230 kV interconnection and network-upgrade costs, and cluster-study reforms under FERC Order 2023. NorthWestern Energy 2026 Montana IRP, 2026-05
  • The North Plains Connector continues to matter for data-center economics and resource adequacy. NorthWestern describes Grid United’s approximately 420-mile high-voltage direct-current project and reports that adding it in modeling reduced 20-year portfolio net-present-value costs by about 2%. NorthWestern Energy 2026 Montana IRP, 2026-05
  • Local project outcomes show that power timing can decide siting. The TAC/Great Falls project withdrew in late 2025 because power timelines did not fit, and the Sabey Butte land agreement ended in 2026 before energy issues were resolved for that site. KRTV, 2025-11-19; NBC Montana, 2026-06-01

Notes / open questions

  • The PSC had not decided Docket 2026.04.023 by July 17, 2026. The tariff must therefore be described as proposed and pending; intervention requests and the coalition’s call for a separate class are advocacy positions, not Commission holdings. Montana Free Press, 2026-06-30; Daily Montanan, 2026-07-14
  • Public-records and confidentiality disputes remain unresolved in the reviewed public sources. Earthjustice’s March challenge argues that the PSC protective order over NorthWestern’s data-center letters of intent blocks informed participation; no later public disposition was identified through July 17. Earthjustice, 2026-03-11
  • County land-use approval does not resolve energy cost allocation. Missoula County used zoning authority to impose a temporary siting pause, while utility rates, service agreements, and cost assignment remain within the PSC proceeding. Missoula County Voice, 2026-07-10; Montana PSC notice via Daily Inter Lake, 2026-06-10