Inverter Dispatch
Background
In November 2025, the Australian Energy Market Operator (AEMO) launched the Inverter Dispatch initiative to address an emerging challenge in maintaining power system security, as the National Electricity Market (NEM) transitions to a grid with a higher penetration of inverter-based resources (IBRs).
The initiative responds to the drastically increasing need for streamlined inverter management to maintain power system security, with the current manual approach unsustainable for both AEMO and market participants.
The initiative builds on existing market systems and operational frameworks to automate the communication of, and monitor compliance with, inverter limitations. By reducing reliance on manual phone calls and enabling automated, real-time responses to inverter limits, the initiative aims to streamline operations and enhance system security. It also seeks to provide greater transparency and predictability for participants, while underpinning AEMO’s ability to manage a secure, modern power system.
AEMO’s newly proposed approach will result in:
- automation of inverter limit communication, allowing IBR operators to receive limits (through market systems and SCADA) and respond to them;
- improved consistency and efficiency in managing inverter-based resources across all NEM regions;
- reduced operational risks and manual workload for both AEMO and participants;
- enhanced readiness for future increases in inverter-based resources; and
- strengthened processes for monitoring and ensuring conformance with inverter limits.
The initiative sets out a series of implementation milestones, commencing with industry engagement and system updates with an interim solution to be made available for early adopters from March 2026, followed by a broader rollout and further automation targeted for late 2026. This staged approach is designed to ensure a smooth transition for all stakeholders as the NEM evolves towards a more resilient and sustainable future.
High-Level Implementation Assessment (HLIA)
The purpose of the HLIA is to provide an overview of how the Inverter Dispatch initiative will be implemented. This aims to assist affected participants in planning their own implementation timelines and assessing potential impacts.
AEMO published a Draft HLIA (v0.1) on 19 December 2025, requesting stakeholder comments and feedback by Friday 13 February 2026.
AEMO has now published a Final HLIA (v0.2) on 15 May 2026. This final HLIA discusses stakeholder feedback received in response to the draft HLIA and provides further and more detailed information on the system impacts and implementation pathway.
The final HLIA will only be updated during project implementation if there is material change in the implementation approach – for example, if detailed design reveals elements that affect the industry’s or AEMO’s readiness. Stakeholders should refer to the initiative webpage and initiative updates provided via AEMO’s NEM Reform forums for up-to-date implementation information.
Industry engagement
This initiative forms part of AEMO NEM Reform Program and market participants can get involved by visiting:
Reference information
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What is the Inverter Dispatch Initiative?
The Inverter Dispatch initiative is an Australian Energy Market Operator (AEMO) reform initiative designed to improve how limits on inverter‑based resources are communicated and managed to maintain power system security as more renewable energy connects to the grid. It responds to the rapid growth of inverter‑based generation such as solar, wind and batteries, where the existing manual process for managing inverter limits, often relying on phone calls is no longer sustainable. The initiative introduces a more consistent and increasingly automated approach and primarily affects operators of inverter‑based resources connected to the National Electricity Market, while also supporting AEMO’s ability to securely operate the power system as renewable penetration increases.
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What are inverter based resources?
Inverter based resources (IBRs) are power system assets that connect through electronic inverters rather than traditional spinning generators. Examples include large scale solar farms, wind farms and battery energy storage systems.
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What is an inverter limit?
An inverter limit is a temporary restriction on how many inverters at a power station can be online at one given time. These limits are used by AEMO to help manage system strength and maintain a secure and stable power system during certain network conditions.
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How are inverter limits managed?
Currently, inverter limits are often communicated manually by AEMO operators, typically via phone calls to generators. This can be time-consuming and challenging during periods when many sites are affected at once.
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Does this initiative change the electricity market rules?
The Inverter Dispatch initiative works within existing market and operational frameworks. Any future changes to compliance or enforcement would be subject to separate rule change processes and industry consultation.
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Do inverter limits or caps only apply to solar, wind & batteries?
Anything that is connected to the network via inverters i.e. Inverter Based Resources (IBRs) – currently only solar, wind and BESS in the NEM.
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Does AEMO receive number of inverters online via SCADA?
Yes, for the vast majority of Inverter Based Resources in the NEM.
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How are NSP limits advice converted to constraints and how do we identify these constraints?
NSP limits advice are translated into constraint equations by AEMO which are used in NEMDE.
ID is of the form REGION_STR_DUID_##_I
E.g. N_STR_FINLYSF1_49_I
Inverter limits are intended to provide information on inverter numbers in addition to inverter limit constraints.
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And where can I find more information on these constraints?
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Can NEMDE optimise inverter numbers?
No, NEMDE can only control MW. These inverter limit constraints violate if the number of inverters online remain above the limit (even if the plant is meeting its new dispatch target, say 0 MW) – this is the current system and is not changing.
However, AEMO is working on a project that extracts the inverter limit information (from existing constraints) and sends it to participants via the AEMO EMMS Data Model by Q1 2026 (Project ‘Interim Solution’), and via SCADA signal by the end of 2026 (Project ‘Enduring Solution’).
This will make it easier for participants to understand and respond to their current inverter limits from AEMO.
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Could we expect NEMDE to calculate inverter limits and populate DispatchLoad table?
NEMDE does not calculate inverter limits, these are determined from the constraint equations based on limits advice received from NSPs.
The constraint RHS is converted per DUID into the values sent to the ‘Predispatchload’ and ‘Dispatchload’ tables in EMMS Data Model. This will appear in the new ‘ELEMENT_CAP’ field.
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Do limit equations specify Max number of inverters per region or subregion or DUID level?
DUID level.
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I have checked the current 'Dispatchload' tables - I see the Inverter Cap field is blank/NULL - does that mean no restrictions?
We can confirm ‘NULL’ will mean no restrictions on number of inverters online (i.e. no limit). As mentioned earlier, AEMO will populate this data by the end of Q1 2026 as part of the Project Interim Solution for Inverter Dispatch.
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We have received 'ELEMENT_CAP' data for some of our QLD sites where the 'ELEMENT_CAP' values appear to be equal to their maximum number of inverters for the DUID. Why is this value not showing 'NULL'?
For parts of QLD there are ‘system normal constraints’ which will show an inverter cap value equal to the maximum number of inverters available at the DUID, when it is otherwise unrestricted. The reason for the non-NULL values in ELEMENT_CAP field is that these are technically constraint conditions, but non-binding and not impacting the max. no. of inverters you can have in-service at your plant/DUID.
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Once the inverter numbers are restricted then participants will need to manually rebid unit availabilities - Is this correct?
Our current view is that participants are expected to appropriately bid and ramp the output of their plant as required within the existing dispatch system to the capability of their plant – please also refer to our High Level Implementation Assessment (HLIA) v0.1 document (under section 2.1) at: Inverter Dispatch
However, AEMO is currently investigating implementing MW constraints to better reflect capability in pre-dispatch and PASA, which may also assist participants with rebidding requirements.
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If a BESS had a grid-forming inverter, would that make any difference to the voltage oscillations compared to a grid-following inverter, and could they still be capped by limits (either for MW or inverter numbers)?
As grid-forming capability differs from OEM to OEM in terms of definition and approach to provide such capability, it cannot be completely ruled out that a grid-forming IBR would not contribute to voltage oscillation.
TNSPs have advised grid-forming inverters may still need to have limits applied, particularly if there is islanding risk, and/or if the IBR mostly behaves like a grid-following inverter in most respects.
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Can we see these binding constraints at the moment, and where are they most likely to impact participants with inverter based resources?
Binding constraints at the moment are mainly in NSW (Central West and South West) under certain outage conditions; however we may see similar constraints for other NEM regions in future (e.g. parts of QLD and VIC, which are connected to those impacted areas in NSW).
Participants can currently see relevant constraints to their units in real-time via Dispatch reports, and indicative inverter limits via Pre-Dispatch reports via EMMS Data Model.