NorthWestern Energy - (SD)

What This Utility Data Tells You

NorthWestern Energy - (SD) is an investor-owned utility operating in South Dakota under EIA identifier 13809. It reports service to approximately 64,654 customer accounts and generated about $0.17 billion in annual electric revenue. 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 - (SD) customer experienced 116.5 minutes of power interruptions, the industry-standard SAIDI metric (System Average Interruption Duration Index). That is comfortably under the 120–180 minute national benchmark range, a sign of solid grid resilience and quick outage response. Over the same period, SAIFI (outage events per customer) was 1.37, putting the typical customer at roughly 1 distinct interruption that year. Excluding major event days (hurricanes, ice storms), SAIDI drops to 73.9 minutes, the gap between that figure and the headline 116.5 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 - (SD), which lets you see whether reliability is trending up or down rather than judging from a single snapshot. SAIDI dropped from 159.0 to 116.5 minutes across that span, a direction regulators and prospective customers tend to watch closely.