Hiccups at Loy Yang A4 (Part 1)

With one of our running copies of ez2view, we’ve coded ‘Notification’ rules to alert us via email each time a coal unit switches off.

The theory is that most* of these units will run (at least at minimum load) whenever they are available … although:

(a)  As we noted at the end of 2022 via the GenInsights Quarterly Update for 2022 Q4, ‘Unavailability of coal units hits 24% across calendar 2022’.

(b)  And on top of this, we are increasingly seeing (*)  cases, such as for YWPS2 here where higher cost coal units are placed in ‘Inactive Reserve’ or ‘Economic Outage’ status because of the ongoing growth of the rooftop PV juggernaut.


In the past couple days we’ve received a few different email alerts relating to Loy Yang A unit 4 switching off a number of times … as I’ve quick summarised in the ‘Unit Dashboard’ widget from ez2view here at the 11:30 dispatch interval, looking back 4 days:


In this window, we can see that:

0)  The unit had been on outage up until the afternoon of Saturday 6th January 2024, at which time it came back online; but

1)  The unit tripped in the 09:15 dispatch interval (NEM time) Monday 8th January 2024

… not shown in the image, but the rebid reason references ‘safety valve issues’.

2)  The unit started coming back online at 12:20 … but again tripped in the 22:55 dispatch interval on Monday 8th January 2024:

… this trip is shown in the table in the image above – but the surrounding rebid reasons don’t clearly nominate a particular reason for this trip.

3)  The unit started coming back online at 02:30 this morning (Tue 9th Jan 2024) but has again just tripped in the 11:10 dispatch interval this morning

… too soon for ‘Next Day Public’ bid data to be visible, and potentially indicate the reason for this third trip.


Looking back 2 weeks

Looking a little further back, via the ‘Generator Outages’ widget in ez2view at the 11:30 dispatch interval, we see that the unit outage shown at the start of the 4 day recent history above was also a forced outage:


This forced outage (let’s call it #0) began on Friday 29th December 2023 and ended Sat 6th Jan 2024.


Looking back 1 year

Readers might recall that we’ve written before about how coal units (any units involving complex processes, like a steam cycle) sometimes experience hiccups like these three trips coming back from an outage.

Keeping this in mind, I opened GenInsights Quarterly Update for 2023 Q3 (our most recently published report, as we’ve only just started working on 2023 Q4) and flip to page 232/282 to look at what has been calculated as the 12 month performance for coal units from Q4 2022 to Q3 2023:


In the 12 month period focused on in this report (from 2022 Q4 to 2023 Q3) we see that Loy Yang A4 experienced a run of good availability (i.e. 8,416 hours available and 344 hours on planned outage in December 2022) … which is in contrast to the past 2 week period.


A gap for 2023 Q4

As noted above, the 12 month gantt chart spans from from 2022 Q4 to 2023 Q3 – and we’re only just starting to complete the analysis for GenInsights Quarterly Updates for 2023 Q4,.

So there’s a gap in this analysis for most of Q4 2023.




A quick note about Callide C3

Unrelated to the above, but following from the article of 30th December 2023, we note in the the ‘Generator Outages’ widget in ez2view that:

1)  The expected return to service date for Callide C3 is still sitting at Wednesday 24th January 2024

2)  Which is now only 15 days away!

Speaking about Callide C3, I did see on the weekend Brendan Little’s update on LinkedIn about the roof going on at the repaired cooling tower:






PS1 … also noticed by Geoff Eldridge

A little after this article was published I saw Geoff Eldridge also post about this via LinkedIn here:


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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