NorthWestern Energy (Montana)
Large-load tariff for data centers: what is on file, the terms the filings state, and where each fact comes from. Terms a filing does not state are marked, never guessed.
StatusPending Last reviewed 2026-10-14
Applies at5 MW or greater of new electric service
What the filing saysFiled with the Montana Public Service Commission on March 31, 2026 as a proposed 'Large New Load Tariff,' establishing requirements and contract terms for customers seeking new electric service of 5 MW or more. Pending PSC approval as of this research -- not yet adopted. As described in company and news coverage (tariff text not read): loads of 5 to 49 MW follow a standardized process with mandatory protections and no case-by-case approval; for loads of 50 MW or more NorthWestern would file the executed service agreement with the PSC for approval before service starts, with longer minimum terms; provisions cover minimum service periods, minimum demand and energy billing, performance assurance and collateral, and termination costs. A five-year agreement with an early-exit penalty was reported for the smaller tier. Intervention requests were being reviewed in June 2026. Separately, an existing Schedule GSEDS-2 serves transmission-level customers (EEI).
Stated terms
This tariff does not yet have terms we can tabulate. The status text above is what the filings and our source state. See the source below.
Source
Daily Montanan and S&P Global Market Intelligence coverage (dailymontanan.com, spglobal.com) of the PSC filing; Montana Free Press (June 30, 2026); NorthWestern Energy's own public statements (northwesternenergy.com). Primary PSC docket text not independently read during this research.
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Screening information from public filings, not legal or investment advice. Tariffs change; confirm the current terms with the utility and the commission before relying on them.