SAIDI
99 min per year
Average outage minutes (2023)
Arizona Public Service Co is a investor-owned utility operating in Arizona under EIA identifier 803. It reports service to approximately 1,370,930 customer accounts and generated about $4.34 billion in annual electric revenue, with a service footprint spanning 276 ZIP codes. As an investor-owned utility, it operates under state public utility commission oversight that reviews rate cases and reliability performance.
In 2023, the average Arizona Public Service Co customer experienced 98.6 minutes of power interruptions — a metric called SAIDI (System Average Interruption Duration Index). That places this utility well below the 120–180 minute national benchmark, signaling strong grid hardening and fast restoration practices. SAIFI — the average number of outage events per customer — was 0.88 for the same period, so customers statistically faced roughly 1 distinct interruption that year. Excluding major event days (hurricanes, ice storms), SAIDI drops to 82.1 minutes — the gap between that figure and the headline 98.6 reveals how much weather, not day-to-day infrastructure, drove outages.
The EIA dataset includes 4 years of continuous reporting (2020–2023) for Arizona Public Service Co, which lets you see whether reliability is trending up or down rather than judging from a single snapshot. SAIDI has increased from 84.5 to 98.6 minutes, which may reflect either worsening weather exposure or delayed grid modernization. All figures on this page come directly from EIA Form 861, the federal annual electric power industry survey, with service territory ZIPs sourced from OpenEI — you can cross-reference them with your own utility bill or use them when comparing providers before relocating.
SAIDI
99 min per year
Average outage minutes (2023)
SAIFI
0.88 interruptions/yr
Outage frequency (2023)
Customers
1,370,930
Served in Arizona
99 minutes per customer per year
Minutes without power per year (2023)
| Year | SAIDI (min) | SAIDI nMED | SAIFI | Customers |
|---|---|---|---|---|
| 2020 | 84.5 | 78.6 | 0.860 | 1,285,518 |
| 2021 | 106.5 | 87.4 | 1.020 | 1,314,670 |
| 2022 | 138.1 | 84.0 | 1.040 | 1,345,376 |
| 2023 | 98.6 | 82.1 | 0.880 | 1,370,252 |
SAIDI nMED = SAIDI without major event days. Source: EIA Form 861.
Arizona Public Service Co serves 276 ZIP codes in Arizona.
Arizona Public Service Co had a SAIDI of 98.6 minutes in 2023, meaning the average customer experienced about 99 minutes of outages that year. This is below the national average, indicating above-average reliability.
Arizona Public Service Co is classified as a IOU serving Arizona. Investor-owned utilities (IOUs) are for-profit companies regulated by state public utility commissions.
SAIDI (System Average Interruption Duration Index) measures the average total minutes per year that a customer of Arizona Public Service Co experiences power outages. A lower SAIDI indicates better reliability. The national average is roughly 120-180 minutes per year, so comparing Arizona Public Service Co's SAIDI to that benchmark shows whether this utility is above or below average.
Arizona Public Service Co serves approximately 1,370,930 customers in Arizona. Customer count can affect reliability metrics because larger utilities may face different infrastructure challenges compared to smaller ones.
Arizona Public Service Co has 4 years of reliability data (2020-2023). SAIDI has remained relatively stable over this period. Review the trend table above for year-by-year detail.
SAIDI "without major event days" (SAIDI nMED) excludes outages caused by hurricanes, ice storms, and other catastrophic weather events. It better reflects day-to-day infrastructure reliability rather than vulnerability to extreme weather. Both standard SAIDI and SAIDI nMED are shown in the reliability trend table above.
Disclaimer: This information is provided for informational purposes only and does not constitute professional advice. Data is sourced from the U.S. Energy Information Administration (EIA) Form 861. Consult a qualified professional before making decisions based on this data.
Read our methodology — how this data is sourced, computed, and verified.