Integrating Energy Storage Systems project


AEMO has established the Integrating Energy Storage Systems (IESS) project under the NEM Reform Program to carry out the procedure and system changes arising from the IESS rule and to support industry readiness for the IESS changes.

Forming a part of the Energy Security Board’s (ESB) National Electricity Market (NEM) 2025 reform portfolio, the IESS rule seeks to better integrate storage and hybrid systems into the NEM.

The IESS rule comprises four distinct high-level changes:

Implementation date Change Description

Fri 31 Mar 2023


SGAs providing FCAS


Aggregators of small generating and storage units can now provide ancillary services (if they choose to do so). Information and resources for Small Generation Aggregators are available through the IESS Participant Toolbox.

Wed 09 Aug 2023

Aggregated dispatch conformance

Completed 9 August 2023.

Aggregate Systems can choose to register for aggregated dispatch conformance (ADC).

  • ADC provides an Aggregate System with the flexibility to conform to its dispatch instructions by dispatching energy at the connection point from any combination of its units (with some restrictions), rather than individually on a unit-by-unit basis.
  • Includes minor changes for Battery Energy Storage Systems (BESS). AEMO will be using the ADC mechanism to monitor net dispatch conformance for a BESS across its scheduled generating unit/scheduled load pair, as a Target Aggregate.

Information and resources for participants are available through the IESS Participant Toolbox.

Sun 02 Jun 2024

IESS retail and settlement changes

Significant changes to the calculation method to be used for Non-Energy Cost Recovery (NECR):

  • Recovery calculations are to consider the gross (consumption separate from generation) energy amounts of all participants, rather than current approach using net energy (generation – consumption) of specific participant types
  • Major settlements database structure changes are required to enable the new calculations, these changes will flow into the Data Model and affect:
    • Participant reconciliation and reporting activities
    • AEMO data provision
    • Embedded network management changes to ensure that the parent has the appropriate gross energy volumes available for settlement.

Information and resources for participants are available through the IESS Participant Toolbox.

Mon 03 Jun 2024

IESS registration, classification and bidding changes

Introduction of Integrated Resource Provider (IRP) participant type and bi-directional unit (BDU) bidding, scheduling and participation, with impacts for BDU participants and bidding system vendors/developers.

Information and resources for participants are available through the IESS Participant Toolbox.

This web section provides participants and the broader industry with a one stop shop for information regarding the IESS implementation project.

Industry engagement

The IESS project forms part of AEMO’s NEM Reform program. This includes forums and working groups for affected participants and other related bodies to support the implementation. Visit the NEM Reform Program webpage for information about how to get involved and access meeting contents and outcomes. 

The IESS Working Group (IESS-WG) has closed and its work transitioned into the Program Forums and Working Groups. The project thanks stakeholders who contributed to the IESS WG. Meeting contents and outcomes remain available on the Working Group landing page

AEMO also welcome stakeholders to contact the project directly at

For more information, please contact

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