A quick look back at the coincident short outages at Tarong 1 and Tarong 2 yesterday

Yesterday I’d written two articles about TARONG#1 and TARONG#2 in quick succession:

• Around 10:00, I wrote about ‘Two units at Tarong come offline Wednesday morning 28th Feb 2024 … not planned in advance’.
• Early afternoon I had then written ‘Both Tarong units back online ~3 hours later’.

Following from this, there was a bit of speculation internally about what the possible cause might have been for the coincident outages (especially given that the ‘coming off’ profile and ‘coming back on’ profile were so very similar between units, just spaced slightly apart in time).

What happened on Wednesday 28th February 2024 at TARONG#1 and TARONG#2

With the advantage of ‘next day public’ data we can look at more now, via the ez2view software as follows…

TARONG#1 (offline 09:15 Wednesday 28th February 2024)

Firstly here’s a view of the past two days at the TARONG#1 unit, which was the one offline first yesterday, and also back online first as well.

Using the ‘Bids & Offers’ widget we can show Bid Stack and Bid Table, which shows ‘final bids’ (i.e. a concatenation of the real bids NEMDE assessed across all dispatch intervals, taking into account all rebids) ‘Capped and Dispatch Availability’:

In the table underneath we see the bids and rebids taken into account in that 2-day period (remember bids not visible from 04:05 this morning yet).  I’ve selected* two in particular and used the ‘Bid Comparison’ function on the second tab, which we show here:

* for those with licensed access to the software, remember this is a ‘Control Click’ function.

As noted there, it seems that:

1)  Tuesday morning 27th February 2024 they conducted a ‘Stem Free Test’ on the unit

2)  Perhaps as a result of that, it was determined shortly afterwards (i.e. by 11:23 when new ‘Daily Bid’ submitted for the following day) that a short outage was required for Wednesday morning 28th February 2024.  Part of this outage would entail a rapid ramp down, and a rapid ramp up.

TARONG#2 (offline 09:40 Wednesday 28th February 2024)

For illustration purposes, a very similar decision process seems to have been followed for Unit 2:

So to sum up, the outages did appear to have been planned … just at very short notice – so not appearing days in advance in the ‘Generator Outages’ widget (or noted in the first article):

• perhaps in response to something observed in the two ‘Stem Free Tests’ conducted).
• My real engineering experience is too rusty to speculate more on what those reasons might be?

Perhaps some more learned readers still working as engineers within thermal power stations might suggest more in comments below?

No change in outage plans

Perhaps more importantly, a quick glance at the ‘Generator Outages’ widget in ez2view shows no change in outage plans within the next 2 weeks for the Tarong units – so we might assume whatever the purpose of the short outages, it might have been effective?

But that’s all for now…