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Reliability

Reliability is a continuous supply of electricity. We aim to meet the reliability targets set by the Australian Energy Regulator (AER) each year. We do this by working to improve the supply network.  


Electricity reliability measures

In 2021, the electricity regulatory period changed from calendar year to financial year.

Our reliability targets are listed below. These targets are updated annually.   

1 July 2021 – 30 June 2022 (FY22)
Supplied by Urban feeder #
Supplied by Short Rural feeder #
Supplied by Long Rural feeder #
On average, the number of minutes a customer will experience loss of supply due to unplanned interruptions per year. (e.g. lightning, storm, fauna) (USAIDI)
87 mins
195 mins
294 mins
On average, the number of unplanned interruptions a customer will experience per year (longer than one minute).(USAIFI)
0.89
2.01
2.63
On average, the duration of an unplanned customer interruption (UCAIDI)+
98 mins
97 mins
112 mins
On average, the number of momentary interruptions (less than one minute) (MAIFI)
2.82
5.66
9.92
On average, the number of minutes a customer will experience loss of supply due to planned interruptions per year (e.g. maintenance) (PSAIDI)*
148mins
240 mins
325 mins

* No AER targets. Internal only based on 2016-2020 (5yr) weighted average.

+ Derived based on USAIDI & USAIFI targets.


The AER defines:

  • An Urban feeder as a High Voltage circuit with load density greater than 300kVA/km. Covers outer metropolitan suburbs and major towns
  • A Short Rural feeder as a High Voltage circuit which is not an Urban feeder with total length less than 200 km. Covers areas near major towns
  • A Long Rural feeder as a High Voltage circuit which is not an Urban feeder with total length greater than 200 km. Covers more remote rural area

If you would like to know more, please contact us