As required by Section 3.15 of the Electricity System and Market (ESM) Rules, the Coordinator of Energy (Coordinator) completed the first review of the Essential System Services (ESS) Process and Standards (the Review) in December 2025.
The review of the ESS Process and Standards and the basis for setting the ESS requirements aims to assess whether the existing framework is effective to ensure power system security and reliability can be maintained as the energy transition continues.
An ESS Framework Review Working Group (ESSFRWG) was established by the Market Advisory Committee to support the Review.
As part of the review process, the Coordinator published a Consultation Paper in November 2025, that contained the inputs and results of the technical reviews conducted pursuant to clause 3.15.1A and clause 3.15.1B and cost-benefit studies, and outlined the 5 proposed Review Outcomes:
- AEMO to update and publish the technical and operational guidelines relating to FCESS quantification and dispatch processes:
- ESS Quantities WEM Procedure;
- Dynamic Frequency Control Model (DFCM) process
- Real Time Frequency Stability tool process; and
- Supplementary ESS Mechanism documentation.
- AEMO to review the inputs, parameters and assumptions for the DFCM and test whether they should be updated to reflect current system conditions and drive relevant and correct outputs.
- Increase the Rate of Change of Frequency (RoCoF) Safe Limit from 0.25 Hz per 0.5 seconds to 0.75 Hz per second to reduce the need for AEMO interventions.
- AEMO to implement a monitoring program over a twelve-month period to track the amount of headroom available from unaccredited Facilities or non-dispatched FCESS Facilities to better quantify mandatory Primary Frequency Response (MPFR) availability to assess the level of Contingency Reserve Raise that could be provided from the inclusion of MPFR.
- Assess the suitability of synthetic inertia (RoCoF Control Service) from Battery Energy Storage Systems (BESS) in complementing synchronous Inertia from rotating machines, and consider potential barriers and suitable incentives for grid-forming BESS to provide such services.
EPWA published for consultation an addendum which included proposed ESM Amending Rules to increase the Rate of Change of Frequency Safe Limit from 0.25 Hz per 0.5 seconds to 0.75 Hz per second, to implement one of the proposed outcomes of the Review.
The consultation period for both the Consultation Paper and addendum closed on 15 December 2025. Stakeholder submissions received and EPWA’s response to these are available below.
The ESM Amending Rules were included in the Electricity System and Market Amendment (Tranche 9) Rules 2025 which were approved by the Minister for Energy on 19 December 2025 and published in the Government Gazette on 23 December 2025 and are available here.
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