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

Market National Electricity Market
StageFinal Report
ConvenorAEMO NEM
Accepting submissions?No
Submissions close18/11/2021

Consultation Timeline

The consultation has been completed with the details of the Final Determination below.

  • First Stage - Issues Paper and Notice of First Stage of Consultation
    19 January 2021
  • First Stage - Submissions Close
    11 March 2021
  • Second Stage - Draft MASS and Notice of Second Stage of Consultation
    14 June 2021
  • Second Stage - Submissions close
    6 August 2021
  • Third Stage - Draft MASS and Notice of Third Stage of Consultation
    28 October 2021
  • Third Stage - Submissions Close
    18 November 2021
  • Third Stage - Final MASS determination published
    22 December 2021

The Australian Energy Market Operator (AEMO) conducted 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 also took 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 was 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.”

The revised MASS (version 7.0) will take effect from 1 February 2022, until that time the current MASS (version 6.0) remains in effect.


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.

Final Determination

Associated Information

At the following link is a draft revision to the Verification Tool and User Guide. This includes:

  • The proposed changes described at section 6 of the Second Draft Determination on the MASS, under the current MASS consultation
  • Additional modifications to the tool effect proposed and other changes to the tool

In addition to feedback provided via formal submissions on section 6 of the second draft determination of the MASS consultation, AEMO will accept feedback provided by 14 January 2022 on the changes to the Verification Tool and User Guide not otherwise described in the second draft determination. Feedback can be provided to Feedback provided on the tool will be considered outside of formal submissions to the MASS and does not form part of AEMO’s Final Determination.

Third Stage Consultation documents

Previous forums

AEMO held a stakeholder forum to facilitate discussion on the second draft determination on Monday, 8 November 2021. A copy of the summary of discussion and presentation are available below. 

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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