AEPC_2026_07 Dispatch Algorithm Formulation

The consultation process

The consultation process is outlined below. Dates are indicative only and subject to change.

Procedure change proposal

Electricity System and Market Rules – Clause 2.10

Date of Notice: 13 July 2026

Matter under consultation

AEMO has commenced the Procedure Change Process to propose amendments to the WEM Procedure: Dispatch Algorithm Formulation to reflect changes made to the Dispatch Algorithm in accordance with clause 7.2.3 and to undertake process improvements.

Amendments have been made to reflect urgent changes undertaken under clause 7.2.3 to improve the operation of the Dispatch Algorithm, regarding the treatment of Facilities to respect relevant Frequency Co-optimised Essential System Services (FCESS) trapezia and address potential violations of safe limit and defined contingency constraints. Further proposed amendments have been informed by AEMO’s operational experience and observed need for uplift to address emergent or potential issues in dispatch.

AEMO has proposed the following amendments to the Procedure:

• updating Constraint Violation Penalties following urgent changes implemented by AEMO in accordance with clause 7.2.3 on 30 October 2025, 5 November 2025, and 4 December 2025.
• reducing RoCoF Control Service Requirement fluctuation when both costs of RoCoF and Contingency Raise services are zero.
• aligning the schedule of a Non-Scheduled Facility where a negative Unconstrained Injection Forecast has been provided.
• improving estimates of a Facility’s potential Droop Response in the Essential System Service pre-processing calculation.
• aligning the Procedure with current system functionality, with respect to relaxation of Enablement Limits for RoCoF Control Service in Pre-Dispatch Intervals in the Pre-Dispatch Schedule and Week-Ahead Schedule.

Improvements of an editorial nature are also made to various paragraphs and explanatory Notes.

 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.

Invitation to make submissions

AEMO invites 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 requests that respondents identify any parts of their submission that they wish to remain confidential, explaining why. AEMO advises 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 encourages 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

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

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 10 August 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

All submissions will be published on AEMO’s website. Confidential information will not be published, other than as specified above.