| Table 11.1 Reliability Metrics of U.S. Distribution System |
| IEEE | Any Method | ||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| All Events (With Major Event Days) | Without Major Event Days | Loss of Supply Removed | All Events (With Major Events) | Without Major Events | |||||||||||
| Year | SAIDI (minutes per year) |
SAIFI (times per year) |
CAIDI (minutes per interruption) |
SAIDI (minutes per year) |
SAIFI (times per year) |
CAIDI (minutes per interruption) |
SAIDI (minutes per year) |
SAIFI (times per year) |
CAIDI (minutes per interruption) |
SAIDI (minutes per year) |
SAIFI (times per year) |
CAIDI (minutes per interruption) |
SAIDI (minutes per year) |
SAIFI (times per year) |
CAIDI (minutes per interruption) |
| 2013 | 227.2 | 1.187 | 191.5 | 111.9 | 0.994 | 112.6 | 225.5 | 1.113 | 202.6 | 215.7 | 1.2 | 179.8 | 106.1 | 0.992 | 106.9 |
| 2014 | 236.2 | 1.257 | 188 | 114.2 | 1.038 | 110 | 244.8 | 1.202 | 203.7 | 219 | 1.22 | 179.6 | 109.7 | 1.019 | 107.7 |
| 2015 | 209 | 1.275 | 163.9 | 117 | 1.073 | 109.1 | 198.2 | 1.163 | 170.4 | 205 | 1.246 | 164.5 | 113.1 | 1.046 | 108.1 |
| 2016 | 268.4 | 1.327 | 202.2 | 119.8 | 1.082 | 110.7 | 257 | 1.23 | 209 | 249.2 | 1.292 | 192.9 | 116.9 | 1.062 | 110 |
| 2017 | 505.9 | 1.42 | 356.2 | 117 | 1.023 | 114.3 | 489.6 | 1.254 | 390.6 | 473.1 | 1.394 | 339.3 | 114.4 | 1.007 | 113.6 |
| 2018 | 349.2 | 1.34 | 260.5 | 121.4 | 1.051 | 115.5 | 338.5 | 1.193 | 283.8 | 346.4 | 1.325 | 261.5 | 117.2 | 1.028 | 114 |
| 2019 | 295.5 | 1.332 | 221.8 | 122.2 | 1.04 | 117.5 | 289.1 | 1.189 | 243 | 284.6 | 1.325 | 214.8 | 118.6 | 1.017 | 116.6 |
| 2020 | 456.1 | 1.385 | 329.3 | 116 | 1.013 | 114.5 | 460.5 | 1.238 | 371.9 | 491.9 | 1.44 | 341.7 | 119 | 1.037 | 114.7 |
| 2021 | 475.8 | 1.436 | 331.2 | 125.7 | 1.039 | 120.9 | 404.5 | 1.294 | 312.6 | 440 | 1.425 | 308.8 | 121.5 | 1.025 | 118.5 |
| 2022 | 333 | 1.426 | 233.5 | 131.1 | 1.09 | 120.2 | 324.7 | 1.315 | 246.9 | 335.5 | 1.405 | 238.8 | 125.7 | 1.064 | 118.1 |
| SAIDI = System Average Interruption Duration Index. It is the minutes of non-momentary electric interruptions, per year, the average customer experienced. SAIFI = System Average Interruption Frequency Index. It is the number of non-momentary electric interruptions, per year, the average customer experienced. CAIDI = Customer Average Interruption Duration Index. It is average number of minutes it takes to restore non-momentary electric interruptions. IEEE refers to the IEEE 1366-2003 or the IEEE 1366-2012 standard. Any method combines data from utilities that use IEEE standard with data from utilities that do not. For utilities using the IEEE method, a Major Event Day is any day that exceeds a daily SAIDI threshold called Tmed. Tmed is a duration statistic calculated from daily SAIDI values from the past five years. For utilities not using IEEE methods, Major Events are self-determined by the reporting utility. Loss of Supply Removed excludes outages due to loss of supply from the high-voltage/bulk power system. |
| For a five minute video explanation of these metrics, go to https://youtu.be/oVH9L0fCMTU. |
| Source: U.S. Energy Information Administration, Form EIA-861, Annual Electric Power Industry Report. |