Procedure changes

AEMO develops and changes Wholesale Electricity Market (WEM) Procedures in accordance with section 2.10 of the WEM Rules. WEM Procedures are more process-related than the WEM Rules and deal with matters including market operation, dispatch and planning, distributed energy resources, security and reliability, and administrative matters. 

The Coordinator of Energy, Economic Regulation Authority (ERA) and Western Power also have responsibility in the WEM Rules for WEM Procedures related to their specific functions.

Summary of procedure changes

All current and past Procedure Change Proposals by AEMO are available here. This page also shows previous Procedure Change Proposals developed by the IMO.

Procedure Change Process

Overview of Procedure Change Process

Under the WEM Rules, only AEMO may initiate the Procedure Change Process in respect of AEMO’s WEM Procedures, however Rule Participants may approach AEMO with suggested changes to procedures.

Any Procedure Change Proposal must be:

  • Consistent with the Wholesale Market Objectives; and
  • Consistent with the WEM Rules, the Electricity Industry Act 2004 and Regulations.

The Wholesale Market Objectives are to:

  • Promote the economically efficient, safe and reliable production and supply of electricity and electricity related services in the South West interconnected system (SWIS);
  • Encourage competition among generators and retailers in the SWIS, including by facilitating efficient entry of new competitors;
  • Avoid discrimination in that market against particular energy options and technologies, including sustainable energy options and technologies such as those that make use of renewable resources or that reduce overall greenhouse gas emissions;
  • Minimise the long-term cost of electricity supplied to customers from the SWIS; and
  • Encourage the taking of measures to manage the amount of electricity used and when it is used.

Once AEMO has developed a new procedure or a proposed amendment to an existing procedure, AEMO publishes a Procedure Change Proposal and a call for submissions from the public. AEMO, the ERA, Western Power or the Coordinator of Energy may convene the Market Advisory Committee (MAC) to discuss the proposal.

Following consideration of submissions, AEMO is required to publish a Procedure Change Report which includes the details of the original proposal, a summary of the submissions received and AEMO’s response to matters raised in submissions, amended wording of the procedure, and a time and date for the new procedure to come into force.


Any person can make a submission relating to a Procedure Change Proposal, during the period indicated for public submissions. Submissions should be provided by email to the nominated AEMO contact and must be received before 5:00 pm (WST) on the final submission date, unless otherwise noted. AEMO is not obliged to consider submissions received after the closing date and time. Any late submissions should explain the reason for lateness and the detriment to you if AEMO does not consider your submission.

A submission must clearly state which Procedure Change Proposal is being addressed, using the reference number. Please relate each submission to a single Procedure Change Proposal. Submissions should be made using the form below.

Contact details for procedure changes

All suggestions for amendment or replacement of an AEMO WEM Procedure should be sent to

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