AEMO commenced a consultation on the Constraint Formulation Guidelines

Also belatedly, we’re noting here now that on Monday 7th April, the AEMO commenced a consultation on the Constraint Formulation Guidelines.

There’s a short (11-page) consultation paper here:

In my quick read, it appears that:

1)   The consultation has stemmed from:

(a)  With respect to Aspect #1, the AEMC’s ISF Final Determination on 28th March 2024; and also

(b)  With respect to Aspect #2, the AEMO’s current consulation on the Congestion Information Resource (CIR).

2)   This AEMO paper covers three aspects of constraints that will be of interest to readers of WattClarity ®:

Aspect #1)  Security Service / Inertia Constraints

The AEMO writes (p7/11) that:

‘The enablement of security services under the ISF Rule commences 2 December 2025 and must be conducted in accordance with the Security Enablement Procedures that are to be published by 31 August 2025.

On 20 February 2025, AEMO met with TNSPs to discuss the formulation for inertia and system strength constraints and how it will align with network limits advice. AEMO also discussed the progress on the contracts for system security services and if there were any outstanding requirements for network service providers.

AEMO has proposed updates to the Constraint Formulation Guidelines (CFG) in a new Section 6.4 for security service constraints. This section proposes the security service constraint equations that will be applied to the system security services scheduler to allow for scheduling of inertia or system strength combinations. These are not applied in NEMDE or PASA but applied through the security service scheduler. Similarly to other constraint equations, these proposed formulations allow for flexibility in the methodology. AEMO commits to providing worked examples prior to market trials. The system security services scheduler will be implemented in December 2025.’

There’s more details inside that we (and many other stakeholders) will need to consider.

Aspect #2)  Increase in minimum LHS Factors

The AEMO notes that:

‘During feedback from stakeholders during the initial stage of this consultation, AEMO was provided with submissions from stakeholders discussing the original change in 2010 to the minimum threshold for left-hand side factors to 0.07. AEMO undertook to review this threshold and whether it was still appropriate in 2025’

There’s more in the PDF above for readers to consider.  Additionally, there are prior articles on WattClarity® that discuss some complications that stem from low LHS factors (e.g. on interconnectors like with respect to the X5 constraints).

(a)  Apologies that I don’t have time to reference specific articles here

(b)  Regardless, this proposed change will be of interest to our readers

Aspect #3)  With respect to Voluntarily scheduled resources

With respect to AEMO’s need to implement the IPRR Rule Change, the third aspect of the consultation notes:

‘AEMO have also proposed updates to include the new term voluntarily scheduled resources as per the IPRR Rule terminology’

… but I don’t think the AEMO expects any feedback on this particular aspect.

The AEMO is seeking submissions by 17:00 (Melbourne time = NEM time at the moment) on Thursday 8th May 2025.