Electric Utilities Sector Supplement - Global Reporting Initiative

Indicator Protocols Set: PR
IP
&
EUSS
EU30: Average plant availability factor by
energy source and by regulatory regime
1. Relevance
Generation plants do not operate all the time because
planned and unplanned outages occur. These outages
can result from maintenance and operational issues.
Unplanned outages have financial implications since
preferred generation capacity is often replaced by less
efficient and more expensive plant.
2. Compilation
2.1 Identify the number of hours of planned outage
(An outage scheduled well in advance (at least two
weeks) of the actual outage).
2.2 Identify number of hours of forced outage
(Unplanned outage that requires the plant to be
taken out of service immediately or before the next
planned outage).
2.3 Report the average availability factor by energy
source and by regulatory regime.
3. Definitions
Availability Factor
The availability factor of a power plant is the amount of
time that it is able to produce electricity over a certain
period, divided by the amount of the time in the period.
Occasions where only partial capacity is available may or
may not be deducted. The availability factor should not
be confused with the capacity factor. Availability factor
(%) = (Total hours of plant in operation during the period
x 100) / Total length of period (hours).
4. Documentation
Operations department.
5. References
International Geothermal Association.
EU
EU
Version 3.0/EUSS Final Version
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