Ancillary services

Ancillary services are used by AEMO to manage the power system safely, securely, and reliably. These services maintain key technical characteristics of the system, including standards for frequency, voltage, network loading, and system restart processes.

AEMO operates eight separate markets for the delivery of Frequency Control Ancillary Services (FCAS), and purchases Network Support Control Ancillary Services (NSCAS) and System Restart Ancillary Services (SRAS) under agreements with service providers. Payments for ancillary services include payments for availability and delivery of the services.

SRAS are reserved for contingency situations in which there has been a major supply disruption or where the electrical system must be restarted.

Ancillary service costs are dependent upon the amount of service required at any particular time and, as these amounts can vary significantly from period to period, costs will also vary.

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