NorthWestern Energy LLC - (MT)

What This Utility Data Tells You

NorthWestern Energy LLC - (MT) is an investor-owned utility operating in Montana under EIA identifier 12825. It reports service to approximately 401,963 customer accounts and generated about $0.89 billion in annual electric revenue, with a service footprint spanning 242 ZIP codes. Investor ownership puts this utility under the regulatory authority of the state public utility commission, which reviews its rate requests and reliability record.

In 2023, the average NorthWestern Energy LLC - (MT) customer experienced 102.5 minutes of power interruptions, a measure known as SAIDI, or System Average Interruption Duration Index. That sits within the 120–180 minute national benchmark range, indicating performance typical of U.S. distribution utilities. SAIFI, the average number of outage events per customer, was 0.93 for the same period, so customers statistically faced roughly 1 distinct interruption that year. Excluding major event days (hurricanes, ice storms), SAIDI drops to 102.5 minutes, the gap between that figure and the headline 102.5 reveals how much weather, not day-to-day infrastructure, drove outages.

The EIA dataset includes 4 years of continuous reporting (2020–2023) for NorthWestern Energy LLC - (MT), which lets you see whether reliability is trending up or down rather than judging from a single snapshot. Over that window, SAIDI moved from 165.5 down to 102.5 minutes, a trend worth noting for anyone weighing capital investment outcomes.