Market Review: Open


The Australian Energy Market Commission (AEMC) Reliability Panel has published a draft determination and draft standard for its review of the Frequency operating standard (FOS) that applies in the national electricity system.
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The Australian Energy Market Commission (AEMC) Reliability Panel has published a draft determination and draft standard for its review of the Frequency operating standard (FOS) that applies in the national electricity system. The Panel invites stakeholders to provide submissions on the draft determination by 2 February 2023.

The Panel is investigating the appropriateness of settings in the standard in light of the ongoing energy market transformation, as conventional synchronous generation leaves the market and inverter-based technologies such as wind, solar and batteries enter the market. It is also timely to revisit the FOS given the recent regulatory reform relating to frequency.

On 8 December 2022, the Panel published a draft determination and draft FOS. The draft FOS includes additions and amendments to support power system security and deliver reduced costs for consumers over the long-term, these include:

  • Updated settings for contingency events — including limits in the FOS for the rate of change of frequency (RoCoF) and the extension of the Tasmanian generation event limit to also include network and load events.
  • Confirmation of the allowable ranges for frequency during normal operation, the primary frequency control band (PFCB), and that the target frequency is 50Hz.
  • Removal of the limit for accumulated time error.

The Panel welcomes feedback on the draft determination and draft FOS and invites stakeholders to participate in the process by:

  • participating in a public forum to engage with representatives of the Reliability Panel: 15 December 2022
  • lodging a written submission with the Panel: by 2 February 2023.

Public forum

The Panel will be holding a public forum on the 2022 FOS review draft determination and draft FOS on Thursday 15 December (AEST). The forum will provide an opportunity for stakeholders to engage with representatives from the Reliability Panel on issues related to the Frequency operating standard. The forum registration page is available here. Registrations are due by 5pm Monday 12 December 2022

Key dates for the review

The terms of reference require that the Panel completes this review by 7 April 2023.

Publish issues paper and terms of reference 28 April 2022
Public forum - Initiation May 2022
Close to submissions to the issues paper 9 June 2022
Receive AEMO advice September 2022
Publish Draft Determination 8 December 2022
Public forum – Draft Determination 15 December 2022
Publish Final Determination By 7 April 2023
Proposed implementation date for the revised FOS 9 October 2023


The AEMC has provided terms of reference to the Panel to initiate a review of the FOS. These terms of reference are published on the project page. Among other issues for consideration, the terms of reference require the Panel to consider whether the terminology, standards and settings in the FOS remain appropriate, or any other issues related to the FOS as determined by the Panel.

Under the National Electricity Rules (NER) the Panel is responsible for determining the power system security standards, including the FOS that apply to the national electricity market (NEM). These standards govern the maintenance of system security and reliability in the NEM; both the mainland NEM and Tasmania.

The FOS define the range of allowable frequency for the power system under different conditions, including normal operation as well as after events that occur that can impact the power system. Specifically, it defines the frequency bands and timeframes:

  • in which the system frequency must be restored following different events, such as the failure of a transmission line or separation of a region from the rest of the NEM. 
  • which are referred to by the performance standards that apply to generator and network equipment in the NEM.

The frequency operating standard for the mainland NEM and Tasmania was last reviewed and determined by the Reliability Panel in 2019.

Consultation on the review commenced on 28 April 2022 with the publication of an issues paper outlining a number of issues for consideration in relation to the control of power system frequency.

This review of the FOS is part of a broader program of regulatory reform relating to essential system services that progresses the Energy Security Board’s (ESB) recommendations in the post-2025 work. The review of the FOS is related to the frequency control element of the ESB’s essential system services workstream to “strengthen the grid” and support power system security. 

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