Rule Change: Completed
Overview
On 25 June 2026, the Australian Energy Market Commission (AEMC) published a final determination and a more preferable final rule to enhance the reliability and supply adequacy arrangements in the East Coast Gas System (ECGS).
The final rule will ensure market participants and the Australian Energy Market Operator (AEMO) have the right tools and information to make efficient decisions when responding to risks or threats to reliability and supply adequacy (RSA) in the ECGS, both in the short- and longer-term.
It also introduces principles to strengthen AEMO’s longer-term gas supply adequacy forecasting and a new governance framework for the gas market price settings reviews. In addition, the changes support AEMO’s appropriate use of the new Supplier of Last Resort (SoLR) mechanism.
The final rule consists of three major components:
- A risk or threat signalling framework - introducing an objective and transparent framework for AEMO to assess, classify and communicate risks or threats to reliability and supply adequacy in the ECGS.
- New governance arrangements for market settings reviews - establishing a Gas Reliability Committee (GRC) and corresponding governance arrangements to support reviews of the declared wholesale gas market (DWGM) and short term trading market (STTM) settings.
- Enhancements to AEMO’s Gas Statement of Opportunities (GSOO) and Victorian Gas Planning Report (VGPR) - including information on forecast supply shortfalls and, where reasonably practicable, more granular regional assessment of gas supply adequacy in the GSOO. In addition, AEMO will consult on and publish its gas supply adequacy assessment methodology.
Background
This is one of four rule change requests aimed at improving the reliability and supply adequacy (RSA) of the ECGS, alongside Notice of closure for gas infrastructure, Projected Assessment of System Adequacy and Supplier of last resort mechanism.
Together, these rule changes form the second stage of the RSA framework, complementing the earlier changes to the NGR applied to the ECGS (stage 1).
The stage 1 changes became effective in May 2023 and expanded AEMO’s powers under the National Gas Law (NGL) to better manage gas supply adequacy and reliability risks in the ECGS from 2023.
Commencement
The final rule requires AEMO to review and update relevant procedures and guidelines by 1 April 2027, enabling the initial risk or threat signalling framework to become operational once they are published. The gas supply adequacy assessment methodology will be published by 1 October 2027 to inform the 2027 GSOO and VGPR. AEMO will complete the scheduled 2026 STTM review before transitioning to a GRC-led review cycle from 2030, with settings applying for the 2032–2036 period.