Integrating Energy Storage Systems project


AEMO 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 project was completed on 3 June 2024 with the NEM Reform Program supporting:

  • A hypercare period until Fri 28 June 2024
  • An industry transition period for bidirectional units until 03 March 2025.


Implementation date Change Description

Fri 31 Mar 2023


SGAs providing FCAS

Small Generation Aggregators (SGAs) can elect to register to provide ancillary services.

Wed 09 Aug 2023


Aggregated dispatch conformance

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

Sun 02 Jun 2024


Settlement and non-energy cost recovery (NECR) changes

Fundamental change - move from current category-based approach to a directional approach:

  • “Generator” and “customer” energy will become “sent out” and “consumed” energy, regardless of the type of connection point
  • Changes to the way NEM participants pay for “non-energy” services i.e. costs of ancillary services, interventions etc.
  • Major AEMO database structure changes required to enable the new calculations, these changes will flow into the Data Model and affect participant reconciliation and reporting activities and also AEMO data provision.

Non-energy cost recovery will change to recovery from cost recovery market participants (CRMPs) based on their proportion of sent-out or consumed energy. CRMPs are: Market generators, Integrated Resource providers, Market customers.

New/updated National Meter Identifier (NMI) Classification Codes

Via the Retail Procedures, 3 new codes and amendments to 2 further codes will be implemented under IESS for:

  • Identifying integrated resource systems (IRS) and removing the current use of two NMIs for grid-scale storage facilities
  • Appropriate application of market fees and unaccounted-for-energy (UFE)
  • Incorporating changes relating to the new Small Resource Aggregator category
  • Enabling appropriate compliance monitoring to protect the integrity of market settlements.

Sun 02 Jun 2024 (SGAs)

On and from Mon 03 Jun 2024 (other)


Introduction of new, near universal participant type – Integrated Resource Provider (IRP)

New category will help simplify registration, particularly for battery participants who currently need to register as both a customer and a generator.

An Integrated Resource Provider will be able to classify a wide range of units.
Facilitated transition to Integrated Resource Provider (IRP) participant type for:

  • Integrated Resource System Participants (BESS and pumped hydro) 
  • Small Generator Aggregators
  • Non-customer load participants

Optional transition for Semi-scheduled generator with non-scheduled battery

Mon 03 Jun 2024


Facilitating bi-directional units (BDU)

A new unit type for plant (such as a battery) that can act as a generator and a consumer of electricity.

IESS Participant toolbox

The IESS Participant Toolbox is a central location for useful resources to help participants understand and prepare for the changes associated with the IESS rule’s implementation.

Industry engagement

This initiative was delivered under the NEM Reform Program and market participants can view published meeting materials by visiting:

IESS  post go-live support for market participants:

The IESS Working Group (IESS-WG) has closed. Meeting contents and outcomes remain available on the IESS working group landing page.

Procedure changes

Many of AEMO’s procedures, guidelines and other documents needed to be changed to implement the Integrating Energy Storage Systems (IESS) Rule.

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