AEPC_2025_23 Supplementary Essential System Service Mechanism Processes

The consultation process

The consultation process is now closed. Relevant dates are outlined below.

Procedure change proposal

Electricity System and Market Rules – Clause 2.10

Date of Notice: 2 December 2025

Matter under consultation

AEMO commenced the Procedure Change Process to develop the WEM Procedure: Supplementary Essential System Service Mechanism (SESSM) Processes as required under clauses 3.11.3, 3.11.4, and 3.15A.46 of the Electricity System and Market (ESM) Rules.

The WEM Procedure: SESSM Processes provides the number of Dispatch Intervals that, once reached, requires AEMO to trigger the SESSM in relation to a FCESS Participation Shortfall. The procedure also provides the framework for procuring SESSM in the event that it is triggered by either AEMO or the Economic Regulation Authority. 

On 6 February 2025 the State Electricity Objective (SEO) replaced the Wholesale Market Objectives under section 3A of the Electricity Industry Act 2004. Following an assessment, AEMO considers the Procedure is consistent with the SEO. Further information on consistency with SEO is provided in the Procedure Change Proposal.

Invitation to make submissions

AEMO invited written submissions on this Procedure Change Proposal, including any alternative or additional proposals may improve the Procedure or better meet the State Electricity Objective under section 3A of the Electricity Industry Act 2004.

AEMO requested that respondents identify any parts of their submission that they wished to remain confidential, explaining why. AEMO advised that it may still publish that information if it does not consider it to be confidential, but will consult with the respondent before doing so.

When making a claim for confidentiality, AEMO encouraged respondents to familiarise themselves with Chapter 10 of the ESM Rules, which imposes obligations in respect to the release of documents.

Meetings

AEMO advised that, before the closing date for submissions, any person may request a meeting with AEMO to discuss the issues and proposed changes raised in the Procedure Change Proposal, stating why they consider a meeting is necessary or desirable.

If appropriate, meetings may be held jointly with other stakeholders. 

Subject to confidentiality restrictions, AEMO generally makes details of matters discussed at meetings available to other stakeholders as part of the final published Procedure Change Report (or earlier, where applicable). 

Closing date and time

AEMO advised that submissions in response to this Procedure Change Proposal should be sent by email to [email protected], to reach AEMO by 5.00 pm (AWST) on 13 January 2026.

All submissions must be in electronic format (pdf or Microsoft Word) and should use the Procedure Change Submission form.

AEMO is not obliged to consider submissions received after the closing date and time.  Any late submissions should explain the reason for delay and the detriment expected if AEMO does not consider the late submission.

Publication

AEMO advised that all submissions will be published on AEMO’s website, and that confidential information will not be published, other than as specified above.