Here’s 7 of the Headline Questions we’re pondering about, following the dramas in Central Queensland on Tuesday 25th May

Alas no great insights to publish today – reflecting the fact that we’re buried in data (and numerous conversations) trying to understand what happened, and the implications, at several different levels.

I thought it would be useful to outline Seven Questions we’ve identified that we’d like to be exploring.

(a)  Note that there are more than these – these are probably enough to share, for now.

(b)  If you can help us understand (or you know of people who can help us) then we’d be keen to hear from you (or them).

With that in mind, here they are…


Q1)  What happened at Callide C?

Clearly something major happened there, but there are only very sketchy details available at present (though a range of theories I have seen, some verging on zany).

More broadly, though, there are also claims being made, and concerns being raised, about the potential declining reliability of our coal-fired power fleet.  We wonder if there are insights we can share (from prior GRC2018, GSD2019 and GSD2020 – along with what’s underway for the upcoming GenInsights21) that can help to paint a clearer picture.

PS3 on Thu 27th May – unfortunately (based on the ABC quotes of CS Energy included here) it does not look like we’re close to understanding this yet.


Q2)  Sequence of events around ‘Event 2 at ~14:06’?

It was clear to me yesterday when I reviewed the high-speed frequency data that there were two discrete events that challenged frequency, separated by 20 minutes (though may have been – indeed were probably – connected in some way that’s unknown at present).

(a)  It appears that frequency had largely recovered from the (near) simultaneous trips of Callide C3 and then (the fire-affected) C4 … I saw something here with the 4-second data that seemed to confirm my conjecture yesterday about this sequence.

(b)  The second event was far larger and more significant … the sequence of which (and causes) are not clear to me.  It seems to be speculation for many people at this stage, and some things that don’t seem to make sense.

PS1 on Thu 27th May – Allan’s short (but very valuable) article from Thursday afternoon will help readers visualise the sequence of events


Q3)   What happened with Wind and Solar in the aftermath?

In  this article I noted about the System Strength constraints and its subsequent impact on Semi-Scheduled Wind and Solar in Northern QLD as ‘Event 3’.   There were a couple questions posed there.

However there are related questions also about rooftop PV and what happened to that as well.

PS4 on Thu 27th May – related to this question I noticed this evening that Giles had written about ‘Output restricted at 11 Queensland solar farms after Callide coal explosion’ referencing changed constraint equations.  Time permitting, will take more of a look.


Q4)   What happened through Tuesday evening 25th March 2021?

There was a bit of running commentary posted (in the lead-up) in Part 2 and then (afterwards) in Part 3.

However there are many other questions that could be explored…


Q5)   Risks through till early June?

With Callide B1, B2 and C3 offline for another week or so, there are questions about residual risk in the interim period from a supply/demand balance perspective.


Q6)   What’s happened in the futures market?

Somewhat related to the above, but also extending further forward, I wonder what has happened in the financial market?  I’ve not had time to look, but do remember seeing something yesterday on social media somewhere…


Q7)   What might be done with C4?

Given the talk of damage (remembering that it’s wild speculation at this stage – even the people onsite won’t have a clear picture yet) there are questions that have popped in our heads about what might be done, moving forwards.

For instance, if the repair is involving generator and/or turbine and likely to cost hundreds of millions, at what point would an alternative be:

(a)  not returning the unit to service; but

(b)  instead taking the $100Ms that would otherwise be spent to buy a whopping battery with long duration storage

(c)  install onsite

(d)  re-register the station as a hybrid

(e)  might even have ancillary benefits of making the operations of C3 more economic?

After all, I read today that Stanwell is slated to install a 150MW battery at Tarong site.  Not sure how feasible the above scenario would actually be, but questions like these have already cropped up for us.

PS2 on Thu 27th May – with additional information provided in an ABC news report, the (scale of the) future challenge becomes clearer.



Anyway, that’s all for today… (if you can help with any of these, please let us know!)

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.

Leave a comment

Your email address will not be published.