Grid reliability · 2024 · 7 reporting utilities

Power outages in Wyoming

The utilities that reported here serve 254,862 customers between them, not the whole state. Weighted by customer count, they averaged 116 min without power in an ordinary year and 2.3 hr once major events are counted. Each figure comes only from the filers that published it, and the counts are below.

What it means

Why there are two numbers

Across the utilities that filed both figures, major events account for 16% of the outage time Wyoming recorded once they are counted: 2.3 hr against 116 min without them, a factor of 1.2×. Solar panels alone do not help during an outage, because a grid-tied array shuts down when the grid does, so riding through one is a battery question. This figure will not answer it: it is an annual average across a utility’s customers, not the length or the load of any single outage. What it does say is how much of the outage time here arrives with major events rather than on ordinary days.

The comparison is drawn from the 7 utilities that filed both figures, which is all of them, so both sides of the ratio describe the same set of customers. The two headline figures above are averaged over everyone who filed each one, so dividing them would not give this number.

Ordinary year116 min29 of 51 jurisdictions, longest first · 7 filings

With major events2.3 hrStorms, ice, and fires included as filed · 7 filings

Interruptions a year0.9×Ordinary year; 1.0× with major events

The bill sideWhat solar offsetsRates and modelled output by utility

The utilities behind the average

Each of Wyoming’s figures is a customer-weighted average of the filings that carried that metric, not of the table as a whole: the ordinary-year average is built from 7 filings and the storm-inclusive average from 7 filings, out of 7 filings that published an outage figure at all. Those are the same utilities on both sides. A utility that filed without publishing a metric, or whose two major-event variants contradicted each other, is absent from that metric rather than counted as zero.

Reported interruption metrics for 2024, largest utility first.
Utility	Customers	Ordinary year	With major events	Interruptions
PacifiCorp	147,268	92 min	92 min	0.9×
Cheyenne Light Fuel & Power	44,112	33 min	33 min	0.5×
Powder River Energy Corp	27,532	4.9 hr	8.3 hr	2.2×
Montana-Dakota Utilities Co	18,970	107 min	107 min	0.7×
High Plains Power Inc	13,979	5.2 hr	5.2 hr	not reported
Black Hills Power, Inc.	2,593	2 min	2 min	0.0×
Fall River Rural Elec Coop Inc	408	16 min	16 min	0.1×

What this page is not

It is a state average of utility filings, not a measurement at any address. Each filing is itself an average over a whole service territory, so a rural feeder and a downtown network arrive here as one number, and nothing in this dataset says how far an individual address sits from it. Nothing here predicts a future year either, and a single severe storm can move a utility’s figure by an order of magnitude.

The methodology page states the sources, the definitions, and the limits. Back to the Grid Reliability Index

Source: U.S. Energy Information Administration, Form EIA-861 reliability file, data year 2024, covering 2024-01-01 through 2024-12-31. The snapshot covers no later period.