AER explores rule changes for semi scheduled generators

The Australian Energy Regulator (AER) has today published an issues paper on semi scheduled generator rule changes. The issues paper presents an analysis on the Council of Australian Governments Energy Council (COAG EC) request for the AER to develop two rule change proposals to support system security in the National Electricity Market (NEM).

Key points of the issue paper include:

  • Analysis and evidence that some semi scheduled generators have begun to deviate from their instructed output and how this behaviour has been increasing over time
  • The impact this behaviour is having on the NEM now, and potentially into the future
  • The benefits of having greater certainty of the output of semi scheduled generation
  • The issues paper also presents potential options for the rule change(s) to address the request.

Now, and into the future, the management of the power system will depend on the Australian Energy Market Operator (AEMO) being able to rely on participants providing energy as forecast and on which the total market dispatch solution and price has been predicated. The proposed rule changes identified in the issues paper seek to contribute to this.

The AER is consulting on the proposed rule change(s) prior to submitting them to the Australian Energy Market Commission (AEMC) as they will be requested to be considered as a fast tracked rule change.

Webex workshop

Interested parties are invited to participate in a webex workshop with the AER on Thursday 2 July 2020, from 9.30 am to 11.30 am AEST.

The workshop will set out the AER’s analysis supporting the need for rule changes and explore the possible solutions identified by the AER as well as allow participants to ask questions and propose more alternatives.

To register for the workshop email by close of business 1 July 2020

Invitation for submissions

Interested parties are invited to make submissions on the issues paper by the close of business on 22 July 2020. Submissions should be emailed to or alternatively submissions can be posted to:

Mr Peter Adams
General Manager, Market Performance
Australian Energy Regulator
GPO Box 520
Melbourne Vic 3001

The AER prefers that all submissions be sent in an electronic format (Microsoft Word) and are publicly available, to facilitate an informed, transparent and robust consultation process. Accordingly, submissions will be treated as public documents and posted on the AER's website, unless prior arrangements are made with the AER to treat the submission, or portions of it, as confidential. Those wishing to submit confidential information are requested to:

  • clearly identify the information that is the subject of the confidentiality claim; and
  • provide a non-confidential version of the submission.


In March 2020, COAG EC requested the AER develop two rule change proposals:

  • That semi scheduled generators be obligated to follow their dispatch targets in a similar manner to scheduled generators; and
  • Semi scheduled generators being required to continually inform the AEMO of any restrictions on their available capacity due to physical factors, ambient weather conditions and their market intentions.
Issued date: 
24 June 2020
AER reference: 
AC 90/20