ST PASA Procedure and Recall Period
Background
In May 2022, the AEMC made a final determination to amend the NER provisions relating to the ST PASA to introduce greater flexibility to ST PASA, revise some ST PASA definitions and obligations and require the commencement of the new ST PASA from 1 July 2025.
The final rule “Updating Short Term PASA” introduced a principles-based approach for AEMO to administer ST PASA, included an obligation to publish a ST PASA Procedure, made changes to ST PASA publication timetable, the definition of ‘energy constraint’ and PASA availability.
AEMO has established the ST PASA Procedure and Recall Period Project under the NEM Reform Program to implement resulting system and procedure changes collaboratively with industry.
Procedure and Recall Period Scope
This project will introduce a principles-based framework, linked to the PASA objective, to guide AEMO’s administration of ST PASA. Other changes, include a requirement for AEMO to publish availability information for individual scheduled resources, and amended definitions of PASA availability and energy constraints.
In due course, this rule will facilitate the implementation of AEMO’s ST PASA Replacement Project. As that project has been delayed beyond its original implementation date, this Project scope only includes initial Procedures that will not materially change the operation and administration of ST PASA, other than in relation to the new information requirements. This Project will also deliver the system changes associated with the recall time and unit level availability information.
Note
AEMO’s processes to manage reliability of supply (including when intervention is necessary) are not included in the scope of this Project. However changes to the PD/ST PASA
calculation are being progressed in parallel through the ST PASA Replacement Project.
High-Level Implementation Assessment (HLIA)
This HLIA sets out the high-level impact assessment of the Rule’s implementation arrangements by:
- Publishing new Procedures which will not materially change the operation and administration of ST PASA other than in relation to the new information requirements.
- Outlining how AEMO’s system and related changes will occur; and
- Enabling participants and other stakeholders to understand and plan for system, process and operational changes as required to implement the Rule through consultation and key implementation dates.
Industry engagement
This initiative forms part of NEM Reform Program and market participants can get involved by visiting:
Timeline
|
Date |
Element |
Description |
|
5 May 2022 |
Updating Short Term PASA final determination |
Publication of the AEMC’s final determination |
|
24 July 2024 |
ST PASA Procedure Stakeholder Workshop |
AEMO will hold a stakeholder workshop outlining the proposed development of the ST PASA Procedure |
|
2 September 2024 |
Initial consultation paper published |
Consultation on the ST PASA Procedure commences |
|
30 September 2024 |
Submissions due for the consultation paper |
First round of consultation closes |
|
28 October 2024 |
Draft consultation paper published |
Draft ST PASA Procedure published for consultation |
|
8 November 2024 |
Technical Specifications published |
Release of the Technical Specifications for participants to understand changes to system design |
|
2 December 2024 |
Submissions due for draft consultation paper |
Second round of consultation closes |
|
24 February 2025 |
Final ST PASA Procedure published |
ST PASA Procedure published and effective prior to rule commencement of 31 July 2025. |
|
21 May 2025 – 27 June 2025 |
Industry testing |
Enables Participants to demonstrate entry of Recall Period data for the associated PASA availability and that AEMO can ingest and AEMO and present relevant data |
|
1 July 2025 |
Release to Production |
Bidding system changes to include Recall_Period and change to Daily Energy Constraint validation |
|
31 July 2025 |
Rule Commencement |
Updating Short Term PASA rule commencement and ST PASA Procedure takes effect |
Implementation toolbox
The Implementation Toolbox is a central location for useful resources to help participants understand and prepare for the changes associated with the rule implementation.
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Readiness
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Technical documentation
General FAQs
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What does it mean to not provide a recall value ie ‘Null’ value or ‘Blank’ value?
Bid submission, via API:
A bidding system would reject an energy bid if, for any interval:- Recall Period attribute is defined, but its value is left blank, e.g.
- “recallPeriod”:
- Recall Period attribute is defined, but its value is non-numeric, or a string enclosed in quotes, e.g.
- “recallPeriod”: <tab key>,
- “recallPeriod”: “<space key>”,
- Recall Period attribute is defined, but its value is a null character (ascii CHR(0) )
If the Recall Period attribute is removed for an interval, bid is accepted and default value of 24000 is automatically inserted.
The following sample JSON bid is accepted
- Recall Period attribute defined in PeriodID 1 with a value of 2
- Recall Period attribute removed in PeriodIDs 2 and 3, system inserts a value of 24000 (default)
The following JSON bid is rejected, because the Recall Period attribute is defined in PeriodID 4, but its value is the null character (JSON schema validation error, ‘Invalid Type, expected Number but got Null’)
Bid submission via AEMO’s web bidding portal:
If the Recall Period cell is left blank for an interval, the Recall Period attribute is removed from the JSON submission for that interval, the bid is accepted and default value of 24000 is automatically inserted. - Recall Period attribute is defined, but its value is left blank, e.g.
-
What is the bid daily energy constraint validation rule?
An energy bid is rejected if the Daily Energy Constraint ≥ registered Max Capacity x 24 hours
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When can we start entering Recall Period in our energy bids?
After AEMO implements the bidding system changes on 1 July 2025.
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When will we see the new PDPASA and STPASA DUID Availability reports?
From 31 July 2025.
-
What time will AEMO implement the bidding system changes?
During business hours on 1 July 2025.
Record of activities
Procedure changes
- AEMO’s Procedures, guidelines and other documents that require changes include:
- ST PASA Process Description (developing new ST PASA Procedure)
- Reliability Standard Implementation Guidelines (RSIG)
- Spot Market Timetable
Reference information
Further information
For further information please contact NEMReform@aemo.com.au.