AEPC_2025_20 Credible Contingency Events

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Date of Notice (version 1): 22 October 2025 [Documents now superseded]

Date of Notice (version 2): 20 January 2026

Matter under consultation

AEMO commenced the Procedure Change Process to propose amendments to the WEM Procedure: Credible Contingency Events and to implement the outcomes of Schedule 4 of the Wholesale Electricity Market Amendment (Miscellaneous Amendments No 3) Rules 2024. These Amending Rules insert additional requirements on AEMO to document the method and factors AEMO takes into account when determining Facility Raise Contingencies, Facility Raise Contingency Risks; and Single Facility Raise Risks as outlined in the consultation materials published by the WA Government on Energy Policy WA’s website.

The Amending Rules were gazetted on 8 July 2024, Schedule 4 is scheduled to commence at 8:00 AM (AWST) on 26 February 2026.

The amended contents of the Procedure reflect the relevant clauses of the ESM Rules (as amended) and AEMOs requirements in relation to the development of this Procedure. Minor editorial changes were also made.

Following an assessment, AEMO considers that the Procedure is consistent with the SEO as an effective process for identifying Credible Contingency Events is essential to maintaining Power System Security. The Procedure aligns to and supports other aspects of the WEM, such as the Dispatch Algorithm, by specifying the methods and factors used when determining Credible Contingency Events and consequentially supporting SEO goals such as Power System Reliability, price outcomes, and reducing greenhouse gas emissions. To the extent permitted under the ESM Rules, the Procedure is technology agnostic, allowing for low emissions technologies.

As per the notice below, AEMO extended the consultation period for AEPC_2025_20 under section 2.10 of the ESM Rules and has published updated versions of the Procedure Change Proposal (version 2) and draft WEM Procedures (v3.2). These documents published on 20 January 2026 superseded the initial documentation published on 22 October 2025. 

Invitation to make submissions

AEMO invited written submissions on this Procedure Change Proposal (version 2), 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, and explain why. AEMO advised that it may still publish that information if it does not consider it to be confidential, but would consult with the respondent before doing so.

When making a claim for confidentiality, AEMO encouraged respondents to familiarise themselves with Chapter 10 of the Electricity System and Market Rules (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 will generally make details of matters discussed at a meeting available to other stakeholders, and may publish those details.

Notice of Extension (revised)

Electricity System and Market Rules – Clause 2.10
Date of Notice: 20 January 2026

AEMO extended the consultation period for Procedure Change Proposal until 18 February 2026 in accordance with clause 2.10.17(a) of the ESM Rules.

This Procedure Change Proposal initially opened for consultation on 22 October 2025 and the consultation process was scheduled to close on 26 November 2025.  AEMO first extended consultation on 19 November 2025, on the basis that issues of sufficient complexity or difficulty have been identified relating to the Procedure Change Proposal, including matters raised during the AEMO Procedure Change Working Group (APCWG) meeting on 23 October 2025 relating to the new proposed content in section 3 of the drafted amended Procedure. The initial extension provided AEMO with sufficient time to undertake additional drafting in response to the matters raised ahead of further consultation on revised documentation under AEPC_2025_20.

In publishing a revised Procedure Change Proposal (version 2) and draft WEM Procedure (v3.2) on 20 January 2026, AEMO advises that it further extended the consultation period until 18 February 2026 to allow sufficient time for stakeholder consideration and feedback. Consultation timeframes under the extension are provided in the revised Consultation Process table above.

Revised 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 18 February 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 the delay and the detriment to you if AEMO does not consider your 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. 

Submissions

There were no submissions.