Amendment of the Market Ancillary Service Specification (MASS) – DER and General consultation

Market National Electricity Market
StageFirst Stage
ConvenorAEMO NEM
Accepting submissions?Yes
Submissions close11/03/2021

The Australian Energy Market Operator (AEMO) is conducting a consultation on the Market Ancillary Service Specification (MASS) with regards to measurements requirements for DERs to participate in the Contingency Frequency Control Ancillary Services (FCAS) markets. AEMO is also taking this opportunity to consult on other important issues in a ‘General MASS Review’ and to undertake a simplification and clarification of the MASS document. 

This consultation is being conducted in compliance with clause 3.11.2(d) of the National Electricity Rules (NER) which requires AEMO to “comply with the Rules consultation procedures when making or amending the market ancillary service specifications.”


General MASS Review

AEMO last conducted a review of the MASS in 2020. This was a limited review aimed at addressing a key issue pertaining to disincentives to providing Primary Frequency Response (PFR). That review, along with feedback from participants, general developments in the FCAS markets and the rollout of the PFR rule have highlighted a range of issues to do with the MASS that should be given due consideration. In addition, AEMO believes there is an opportunity to reformat the MASS to make it a clearer and more useful document for setting out the purpose and nature of the different FCAS products.


In June 2019, AEMO in collaboration with the Australian Renewable Energy Agency (ARNEA), the Australian Energy Market Commission (AEMC), the Australian Energy Regulator (AER), and members of the Distributed Energy Integration Program (DEIP) established the VPP demonstrations. 

This demonstration provided the opportunity to trial the capability for DER to deliver contingency FCAS through VPPs using interim arrangements in the VPP Demonstrations FCAS specification.

The Issues paper for this consultation references evidence and learnings from the VPP Demonstrations and outlines key questions to industry regarding the ongoing arrangements for DER. The paper presents two options for what happens next in relation to DER participation in FCAS markets, and seeks stakeholder feedback on each option. The principles that will guide AEMO in its assessment of these options are also outlined in the paper.

Indicative Consultation Timeline

Following feedback from stakeholders and to ensure due consideration can be given to the wide range of submissions expected, AEMO is extending the first stage of consultation by 2 weeks to provide additional time for formal submissions.  

The below timeline has been updated to reflect the new dates: 


Indicative Date


First Stage

Issues Paper and Notice of First Stage of Consultation

Tuesday 19 January 2021

In progress

Submissions Close

Thursday 11 March 2021

In progress

Second Stage

Draft MASS and Notice of Second Stage of Consultation

Monday 12 April 2021

To be commenced

Submissions close

Tuesday 27 April 2021

To be commenced

Final MASS determination published

Tuesday 8 June 2021

To be commenced

AEMO will also review the timing of the next stages of consultation in light of submissions received and will confirm next steps and timeframes for the consultation after an initial review of submissions.  

For more information, or if you have questions please contact


AEMO will hold 2 stakeholder forums to facilitate discussion, clarification and Q&A regarding the broader MASS review and DER MASS review components under consultation. Forums for the broader MASS review and DER MASS review will be held at different times on the same day. Please see below for dates of the forum(s):

4 February - complete

  • General MASS Review: 10:30 – 11:30am (AEDT)
  • DER MASS Review: 11:30am – 12:30pm (AEDT)

15 April 2021

  • General MASS Review: 10:00 – 11:00am (AEDT)
  • DER MASS Review: 11:00am – 12:00pm (AEDT)

If you are interested in attending the forum on 15 April 2021, please contact by Friday 9 April and provide the following details:

  • Name
  • Organisation
  • Email address
  • Forum(s) that you would like to attend

If you have already provided your details as initially requested, invites will be sent shortly. 


All written submissions must be provided digitally and sent by email to  Submissions must be received by AEMO by 5:00pm NEM time (AEST) on the day specified in the consultation timeline.
Submissions may be provided as follows:

  • Only for the DER MASS review component
  • Only for the General MASS review component
  • Or combined, clearly indicating which component is being addressed throughout the document. 

Submissions for First Stage of Consultation must be received by AEMO by 5:00pm NEM time (AEST) on Thursday 11 March 2021.

Please identify any parts of your submission that you wish to remain confidential, and explain why.  AEMO may still publish that information if it does not consider it to be confidential, but will consult with you before doing so. 

Please note that material identified as confidential may be given less weight in the decision-making process than material that is published.

Public submissions will be published 1 week after submission close date. Any confidential submissions must be clearly marked, or any confidential information within a submission should be clearly marked to make clear to AEMO so that confidentiality can be maintained.


In your submission, you may request a meeting with AEMO to discuss the matter under consultation, stating why you consider a meeting is necessary or desirable.

If appropriate, meetings may be held jointly with other Consulted Persons. Subject to confidentiality restrictions, AEMO will generally make details of matters discussed at a meeting available to other Consulted Persons, and may publish them.

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