One other thing that happened this morning, was the Kogan Creek came offline, as captured at that time in this ‘Notification’ widget alert in ez2view:
This shows that the unit was offline just prior to the 07:35 SCADA snapshot taken for InitialMW for the 07:40 dispatch interval. Let’s walk through several widgets in ez2view to see what we can see in this respect…
(A) Has the outage been reflected in MT PASA DUID Availability at this time?
When we wrote about the Tarong North outage on Friday 14th June, we illustrated (with the ‘Generator Outages’ widget) that the generator had adjusted the availability for a few days forward from that point, reflecting the fact that they knew relatively quickly that it would take a few days to fix.
In this snapshot from the same widget at 14:45 today, we see that the same has not applied for Kogan Creek:
Noting that there’s been an update of this forward-looking data set from AEMO for 09:00 and again for 12:00 this morning, we’re inferring that the generator in this case is still hoping that Kogan Creek will be back before Sunday 23rd June (i.e. which is the start of the MT PASA DUID Availability time horizon at this point).
(B) Was there anything in yesterday’s bids?
Noting that the unit came offline after the 04:00 end of the prior Market Day (i.e. so bids for 07:35 are not visible until tomorrow’s ‘next day public’ release), we still wonder if there is anything visible in the bids for the prior day.
Hence we look at ‘Bids & Offers’ widget in ez2view as follows:
Interestingly we see that:
1) The last 4 bids shown in the Bid Table all reference ‘Unit Commitment’ … which might refer to some form of significant technical challenge with the plant; and
2) In particular the rebid shown as received by the AEMO at 01:26 this morning, and used in the 01:35 dispatch interval, references ‘unit offline revised’.
This, to me, suggests that the generator was aware of some need whereby the unit might need to come offline … 6 hours (or more) prior to the unit actually coming offline. With the ‘Bid Comparison’ function in this widget we can (control-click) select the last two rows and use the magnifying glass highlighted to compare the two to see the following:
What we see here, in comparing the two most recent bids we have access to, does illustrate that CS Energy was planning that the unit would be offline in the early hours of the morning … but for reasons unknown to us (Rebid Reason suggests to ‘See Log’ for details, for those who have access – not us!) they decided that either:
Scenario 1) The unit did not need to come off so early, or
Scenario 2) The unit did not need to come off at all
… there’s insufficient data in the above for us to ascertain which.
Looking further up in the ‘Bid Table’ in the image above, we see that there’s a rebid received by AEMO at 12:15 on Tuesday 18th June 2024 that actually saw the first notice of the need to take the unit offline. Here’s that detailed view:
(C) What’s visible in ST PASA?
The ST PASA data set is currently an opaque data set, because Available Generation is only published on a region-level aggregate basis. So one needs to squint (quite a bit) to see if anything is visible around the time of the change in bid above.
Using the ‘Forecast Convergence’ widget, we see the following:
Remember that this widget allows the user to ‘look up a vertical’ in order to ‘see that other dimension of time’
As highlighted on the image, there was a change in aggregate Available Generation expectation around the time of the rebid from CS Energy … but understanding the meaning of this particular data does take some squinting.
(D) MT PASA DUID Availability in ‘Forecast Convergence’
Not shown here, but a look at MT PASA DUID Availability in the ‘Forecast Convergence’ widget, does show a recent anticipation of a period of reduced availability (i.e. down to 500MW) out till 1st July 2024 – again suggesting some known issue the generator is trying to navigate around.
That’s all I have time for, now…
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