Integrating Energy Storage Systems FAQs

"Integrating energy storage systems into the National Electricity Market" (IESS) is a complex reform with four major components:

1. Market small generation aggregators able to provide contingency frequency control ancillary services (FCAS) - optional for Small Generation Aggregators
2. Aggregate systems (large-scale ‘hybrid’ plant) can opt into aggregated dispatch conformance - optional for aggregate systems
3. Material changes to the non-energy cost recovery framework leading to significant changes to NEM settlement table structures - affects all 'financially responsible Market Participants'
4. Registration, classification and bidding changes for scheduled Battery Energy Storage Systems (BESS

To learn more: Project page

The AEMC made the IESS rule change "to better integrate storage and hybrid systems, and allow greater participation in the market. It also adds flexibility into the rules to create a framework that facilitates innovation in how the market supplies energy reliably and securely to meet the longterm interests of energy consumers.

AEMC IESS rule page

Each of the four IESS reform components has a different start date:

1. Market Small Generator Aggregators (SGAs) were able to start providing contingency frequency control ancillary services from 31 Mar 2023

SGA toolkit

    2. Aggregate systems could start opting into aggregated dispatch     
       conformance from 09 Aug 2023.

ADC toolkit

    3. IESS Retail and settlement changes involving material changes to the non-
        energy cost recovery framework (NECR) and subsequently significant changes
        to NEM settlement table structures will start on Sun 02 Jun 2024.

IESS retail and settlement toolkit

      4. IESS registration, classification and bidding changes, including the introduction of the Integrated Resource Provider (IRP) participant type and Bidirectional Units will start on Mon 03 Jun 2024.

IESS registration, classification and bidding

    5. IESS registration, classification and bidding changes, including the
        introduction of the Integrated Resource Provider (IRP) participant type and
        Bidirectional Units will start on Mon 03 Jun 2024.

Each participant will need to undertake their own assessment of IESS impacts to its operations. To assist with this work, AEMO has published:

• IESS participant impact assessment for IESS components (3) Settlements and (4) Registration, classification and bidding changes

(a) Participant impact assessment

• Participant toolbox containing key information for all components.

(b) Toolkit landing page

AEMO together with the industry have developed and are implementing an industry readiness strategy to assist affected participants prepare for the IESS changes. It includes guidance and participant support, transition and go-live plans, provisions for industry testing and a market trial, and go-live criteria.

Participants will need to subscribe to receive SETTLMENTS_LEGACY to continue to receive this data for settlement dates after 2 June 2024. SETTLEMENTS will also need to be subscribed to at the same time for those implementing v5.3 of the data model.

• Has AEMO reached a final position of new IRS that may enter the market using the same bidding platform systems as existing IRS/ market participants? Are they given until the Mar-25 timeline?
• Will we initiate and process applications for IRPs in advance of the IESS effective date to enable registrations effective from 3rd June 2024?

Existing BESS are listed in the NEM registrations list

Connections pipeline is published in Key connection information list

For participants that start operations from or after the 3rd of June, the default expectation is that they would begin operation as a single DUID. However AEMO is conscious that there will be extenuating circumstances which we will try to accommodate. Where this is the case, the participant will still need to begin single DUID operations before 03 Mar 2025.

Yes. AEMO will notify affected participants once relevant application forms are available. AEMO will also publish an IRP Transition Plan to guide participants regarding this process.

Participants with BDUs will transfer to an Integrated Resource Provider (IRP) participant category. The IRP is intended to be a universal category and provides flexibility in how an organisation may want to organise their other asset types.

The Infographic in AEMC’s final determination [AEMC, IESS Rule, Figure 1 p.6] is a useful resource to identify the interaction of different participant types and the types of units they can classify in relation to the IRP.

AEMO expects that SGAs with exempt battery systems will be able to operate in a similar manner post-IESS, under the new IRP participant category. Further information on how exempt batteries are accommodated under the existing framework is provided in the NEM Small Generation Aggregator Fact Sheet.

UFE changes will commence at the same time as other settlement changes and will not be applied retrospectively.

Once released to pre-production, capability is available for participant testing, and will remain so after the production release. Defects raised after a production release are managed and deployed by AEMO's BAU Support teams.

The IESS market trial has three test phases, each with different affected participants. For details please refer to section 3.1.1 of the IESS industry testing and market trials strategy.

AEMO's IESS Participant Development Support Environment Fact Sheet contains information about who can make use of the PDSE.

AEMO's IESS Participant Development Support Environment Fact Sheet contains information about the PDSE.

Settlements will work for BDUs in the same way as for other connection points configured to be delivered as individual meter reads. That is, in the same way as an existing market generator DUID.

Settlement of consumption and generation will be on a single record in the new Energy Transactions table against the connection point ID of the BDU, with the only difference being the meter type flag.

Given that there is no unique settlement treatment for batteries in future, participants can use the market trial settlement runs on other (non-battery) DUIDs to confirm the new settlements database structure.

Separately, dispatch of the BDU can be validated in pre-production as part of the registration process.

Participants will not see single DUIDs settlement statements in the Market Trial. Testing of BDU bidding and dispatch will occur during Phase 3 of the Market Trial, in April 2024. These new BDU DUIDs will not have settlements as there is no retail meter data to support it.

MT PASA submissions are to be based on the generation (or discharge) side of a BDU. The load (or charge) side of a BDU will not need to be forecasted.

Some BDU Bid Format Validation rules are available here. Note that AEMO has not finalised the validation messaging. Once confirmed and finalized, AEMO will update relevant documents accordingly.

AEMO released information on this via its BDU readiness focus group, held on 12 October 2023. Please view presentation here. 

Yes. DISPATCHTYPE field (DUDETAIL table) will support a new enumerated value of BIDIRECTIONAL. Additionally, UNITTYPE field (DISPATCHABLEUNIT table) will support a new enumerated value of BIDIRECTIONAL.

For detail on new and modified columns associated to tables of the PARTICIPANT_REGISTRATION package, see EMMS - Technical Specification - Data Model v5.3 - March 2024

All sources providing the definition (i.e. Postman and EMMS Tech Spec) are progressively updated for release to participants. The guides and resources are updated and published for the pre-production Release Date are:

EMMS Technical Specification and Data Model 5.3

Data Interchange Online Help

NEM Dispatch Bidding Open API Specification Reference (Postman)

Markets Portal Help

If participants would like to be notified of updates to these information sources, they can subscribe to relevant notifications by asking their company to add them to the support hub mailing list maintained as part of the registration process.

Further, you may consider attending the Market Systems User Group (MSUG), which is an industry group designed to facilitate the continuing improvement of NEM wholesale and retail IT systems, Data Model, and Data Interchange releases (including gas markets). All interested parties are welcome to attend and ask questions.

More Information:

IT change and release management

Market systems user group (MSUG)