AEMC Rule Change (Feb 2020) agrees with much of what ERM proposed – for ‘Improving transparency and extending duration of MT PASA’

This is a belated (and so back-dated) article posted in September 2021 that we’ll be linking back to in future articles.

(A)  Documentation on the AEMC Website

Here are the three key documents relevant to this rule change process.

ERM Rule Change Request (ERC270)
incl Publication of individual DUID data

ERM Rule Change Request (ERC271)
12 Month Extension of Duration

AEMC Final Determination

On 29th March 2019, ERM Power submitted a rule change request to the AEMC for ‘Transparency and Accuracy Amendments’.


From our perspective, one of the key changes proposed in this request was a simple change to clause 3.7.2 (f) (5):

(5) aggregate and individual scheduled generating unit PASA availability for each region;

Also on 29th March 2019, ERM Power submitted a related rule change request to the AEMC for ‘12 Month Extension of Duration’.


ERM noted:

‘Whilst originally satisfactory at a time where the super majority of generation was dispatchable with collectively a high level of firm output and high margins of reserve capacity, the current 24 month (2 year) duration is, in ERM Power’s view, no longer of sufficient duration due to the observed changes in market conditions. ‘

On 20th February 2020 (i.e. the date we chose for this article), the AEMC published its Rule Determination – about Improving Transparency and Extending Duration of MT PASA.


From our perspective, the key outcomes from this rule change was that, from 20th August 2020, the AEMO was:

(a)  To start publishing individual DUID ‘PASA Availability’ for each Scheduled generating facility (though notably not Semi-Scheduled facilities!); and

(b)  To extend the MT PASA time horizon from two years to three years into the future.

For those interested in digging back into the history, the ERM project site for the rule change is currently here.


(B)  Discussion here on WattClarity®

Since becoming aware of the ERM rule change proposals, we have discussed on several occasions in WattClarity articles … such as the following:

(B1)  Discussion prior to the rule being passed

Prior to the AEMC’s final decision, there were several articles published discussing this change:


Article before Rule Change

15th August 2019

We discussed the ERM Rule Change in the context of our (recently released) GRC2018 in the article ‘Transitional challenges require greatly enhanced analytical capability (exemplified in MT PASA Rule Change proposals, for instance’.

18th November 2019

The ERM rule change was referenced again in discussing ‘Probability, Consequence (and Risk) as it relates to summer 2019-20 in the NEM’ with respect to the ESOO 2019.

13th January 2020

Some invisibility of AGL’s Loy Yang A2 following some problems with the unit, provided a good illustration of the value of the proposed rule change in ‘About ERM’s two rule change proposals in at the AEMC’.

Approximately 5 weeks after that article on 13th January, the AEMC published its final determination promoting the rule change.


(B2)  Discussion after the rule was passed

The Rule Changes were made in February 2020 and the substantial changes to the data sets published by AEMO commenced 20th August 2020.

After the data went live, we added it into a new ‘MT PASA DUID Availability’ widget inside of ez2view (from v8 onwards) and have sometimes utilised that widget in articles published here on WattClarity … such as the following:


Article after Rule Change

3rd January 2021

Whilst working on an early beta of ez2view v8, we used the new ‘MT PASA DUID Availability’ widget (using this new data set) in publishing this ‘Status update, on availability of the 48x remaining coal units across Q1 2021’.

21st June 2021

Given the broader dramas that occurred through Q2 2021 that led to considerable price volatility, it was natural to use the same widget in ez2view, utilising the data being published by AEMO to ‘… compare unit availability with expectations prior to Q2 2021’.

21st June 2021

Also on the same day, we posted about ‘Villain #8 – the Invisible Man’ – highlighting the AEMC’s rule change as one case in which the market reform process was (partially*) successful in combating some aspect of lack of transparency in the NEM


*  Unfortunately, the ‘partial’ note was made (as noted in other articles previously as well) because the rule change did not incorporate extending this visibility to Semi-Scheduled plant.

10th July 2021

The ERM Rule Change (and the lack of visibility of availability for Semi-Scheduled plant) was also referenced in relation to this ‘AEMO rule change proposal – replacement of ST PASA process, and data set’.

September 2021

Article to come, and will note it in here.


No doubt others will be added over time.

A number of other articles on WattClarity are tagged with ‘MT PASA DUID Availability’, in relation to the widget of that name inside of ez2view.

About the Author

Paul McArdle
One of three founders of Global-Roam back in 2000, Paul has been CEO of the company since that time. As an author on WattClarity, Paul's focus has been to help make the electricity market more understandable.

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