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

Market National Electricity Market
StageFinal Report
ConvenorAEMO NEM
Accepting submissions?Yes
Submissions close06/08/2021

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 

AEMO has considered submissions and stakeholder feedback and has extended the MASS consultation to seek further independent analysis. A further draft determination will be issued on Thursday 28 October 2021, followed by a further round of consultation and a final determination will be published in December. 

Process Indicative Date Status
First Stage
Issues Paper and Notice of First Stage of Consultation Tuesday, 19 January 2021 Complete
Submissions Close Thursday, 11 March 2021 Complete
Second Stage
Draft MASS and Notice of Second Stage of Consultation Monday, 14 June 2021 Complete
Submissions close Friday, 6 August 2021
 Third Stage    
Draft MASS and Notice of Third Stage of Consultation Thursday, 28 October 2021 In Progress
Submissions Close Thursday, 18 November 2021 To be commenced
Final MASS determination published Wednesday, 22 December 2021 To be commenced

For more information, or if you have questions please contact


AEMO held a Feedback and Information Session on 1 October 2021 to provide stakeholders with an overview of the feedback received during the second stage of consultation that has influenced the decision to conduct further analysis. A copy of the presentation is available below.

AEMO held 2 stakeholder forums to facilitate discussion, clarification and Q&A regarding the broader MASS review and DER MASS review components under consultation.

Please see below for details of the forum(s):

4 February - complete

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

23 June 2021 - complete

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


AEMO received requests for meetings from the following stakeholders:

  • Reposit Power
  • SwitchDin

AEMO also sought to meet with the following stakeholders to understand components of their submissions in further detail:

  • Evergen
  • IntelliHub
  • Landis+Gyr
  • Planet Ark Power
  • Shell Energy
  • Solar Analytics

Summaries of the outcomes of these meetings are available below.

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