The Reliability Panel today published a final report into its review of the definition of unserved energy, which is used in evaluating whether the reliability standard has been met.
The reliability standard, which guides how much electricity capacity is needed, is expressed in terms of wholesale unserved energy – that is, the maximum expected unserved energy from generation and interconnectors must not be more than 0.002 per cent of the total energy demanded in a given year.
The Panel sought to clarify and simplify the definition of unserved energy used in post-event analysis of wholesale supply interruptions by examining what should be included or excluded from the calculation of unserved energy.
The Panel concluded that the unserved energy definition is largely fit for purpose but that it would benefit from minor changes aimed at providing clearer and more accurate information to the market about whether the reliability standard was met, and hence, if there is a need for more capacity.
To progress its conclusions, the Panel has today submitted a rule change request to the AEMC seeking changes to:
- promote transparency of the unserved energy calculation, by requiring AEMO to provide more information on how it calculates unserved energy
- improve clarity of the unserved energy framework, by complementing the definition of unserved energy with a principle to guide AEMO when allocating incidents to unserved energy.
These changes will provide better information, and transparency of information, about how the reliability standard is assessed once an event has occurred.
While the Panel concluded that the existing definition of unserved energy is largely fit for purpose, stakeholders raised other issues which are best examined through a review of the reliability standard. The Panel reviews the reliability standard and settings every four years, and may do so more often if requested by the AEMC. It was last reviewed in 2018.
Media: Bronwyn Rosser, Communication Specialist, 0423 280 341; bronwyn.rosser@aemc.gov.au