Readers here will have noted that the prior week some of the team (including myself) were in Melbourne for All Energy 2025 and associated events.

But that did not not stop us noticing this update on LinkedIn from CS Energy on Thursday 30th October 2025, which is worth noting here for those readers who may not have seen it themselves:

Also worth our readers noting is the News Media Release ‘Callide Unit back online in record time‘ also published on Thursday 30th october 2025.

It’s only just Sunday 2nd November 2025, so we’re a month away from the official start of summer – but storm season is already amongst us in different parts of the NEM, including these impacts in south-central Queensland around Biloela.

Given I had the ‘Bids & Offers’ widget already opened in ez2view, I thought it might be useful to flip to these two coal units to check what was visible in the market data:

About Callide B2 … the trip on Tuesday evening 28th October + another later

From Melbourne we’d written about the ‘Frequency drop with trip of Callide B2 on Tuesday evening 28th October 2025’ on the morning after the trip – and, at the time, I had noted that there was no news :

At the time of making that article, the unit had actually already returned to service in the early hours of the morning.  In this updated (and elongated) trend from the ‘Bids & Offers’ widget, we see that the unit was also briefly offline on Friday afternoon 31st October 2025:

We did not have time to note this at the time … but it is worth noting that this unit trip:

• occurred over two dispatch intervals:
  • a Dispatch Error of +211MW in the 14:40 dispatch interval (NEM time) as the unit output dropped to 126MW; and also
  • noting that:
    • there was an attempt to recover in the 14:45 dispatch interval
    • but the rebid with reason ‘mill trip’ was submitted and received by AEMO at 14:42 (NEM time)
  • a Dispatch Error of +175MW in the 14:50 dispatch interval (NEM time) as the unit output dropped fully offline (to 0MW).
• which came ~45 minutes after the VRE under-performance dragging frequency down that delivered this frequency drop (you can see the slightly later drop in frequency on the chart, coincidentally).

About Callide C4 … the return to service on Wednesday 29th October 2025

The return to service we’d not noted on Wednesday 29th October 2025 … but we had noted the ‘Sharp mainland frequency drop, with trip of CPP_4 on Sunday evening 26th October 2025’.

So with the ‘Bids & Offers’ widget here’s a view looking back a span of 8 days to cover both:

Nothing more to add, at this point.