South Dakota

What This State's Utility Data Tells You

South Dakota has 7 electric utilities reporting to the federal EIA Form 861 survey, of which 7 file full SAIDI and SAIFI reliability metrics. Together these providers serve approximately 0.2 million customer accounts, spanning investor-owned utilities (IOUs), member-owned rural cooperatives, and municipally-owned systems — each with different governance models, rate-setting processes, and reinvestment patterns that shape reliability outcomes on the ground.

The statewide average SAIDI — the mean number of minutes a typical customer spends without power each year — is 73.6 minutes across utilities with reporting data. That places South Dakota below the 120–180 minute national benchmark, indicating above-average grid performance. The average SAIFI — the number of outage events per customer per year — is 0.76, meaning South Dakota customers statistically face fewer than one interruption per year on average. Excluding major event days (hurricanes, ice storms, wildfires), the SAIDI figure drops to 46.3 minutes — the gap between that and the headline 73.6 shows how much weather, rather than day-to-day infrastructure, drives outage time in South Dakota.

Within South Dakota, reliability varies widely: the best-performing utility reports SAIDI of 7.4 minutes while the worst reports 163.8 minutes — a 22.1× spread that typically reflects the difference between dense urban distribution grids and long, rural feeder lines. This kind of within-state variation matters when you're deciding where to relocate, choosing between service territories, or comparing reliability against a home-insurance quote. All figures on this page come directly from EIA Form 861, the federal annual electric power industry survey — use the ranked table below to look up specific providers and review their multi-year SAIDI, SAIFI, and customer-count trends.

The U.S. Energy Information Administration publishes the EIA Form 861 dataset every June, covering all licensed electric distribution utilities across the United States. Each utility self-reports interruption duration and frequency under definitions standardized by IEEE Standard 1366; the agency cross-validates the submissions against retail-sales volume and customer counts before release. Major event days, typically severe weather, are reported in a separate column and excluded from the headline SAIDI and SAIFI to keep year-over-year reliability comparisons meaningful. Use these state-level averages as a starting point, then check each provider's underlying multi-year submission on the federal portal before drawing conclusions about a specific utility.