Frequency drop with trip of Callide B2 on Tuesday evening 28th October 2025

A short note to capture the trip of Callide B2 on Tuesday 28th October 2025 in the five minute period prior to 21:01 (NEM time) that day – as recorded in this ‘Notifications’ widget alert in ez2view:

2025-10-28-at-21-01-ezwview-Notifications-CB2-trip

We can see the unit tripped from almost full load – so it was no surprise to see a sharp drop in System Frequency, and also quick recovery as well (especially given this happened overnight, so (my assumption being that this was) when a larger share of supply coming from units providing PFR):

2025-10-28-at-21-16-NEM-MainlandFrequency

 

 

What’s in the Bids?

Given we’re now past 04:00 and the ‘next day public’ data set is available, we’re able to look into the bids via the ‘Bids & Offers’ widget in ez2view as follows:

2025-10-29-at-06-35-ez2view-BidsOffers-CALLB2

In this case, there’s a rebid very quickly submitted that reveals the trip:

  • Received at the AEMO at 21:03 with ‘Event Time’ as 21:01;
  • And with the rebid reason somewhat cryptically saying just ‘electrical’.

We can also see that the unit has made its way back online overnight.

 

Any news from CS Energy?

Given that there was news posted following the Callide C4 trip recently, I thought it worth checking for news here from CS Energy, but there was none.


About the Author

Paul McArdle
Paul was one of the founders of Global-Roam in February 2000. He is currently the CEO of the company and the principal author of WattClarity. Writing for WattClarity has become a natural extension of his work in understanding the electricity market, enabling him to lead the team in developing better software for clients. Before co-founding the company, Paul worked as a Mechanical Engineer for the Queensland Electricity Commission in the early 1990s. He also gained international experience in Japan, the United States, Canada, the UK, and Argentina as part of his ES Cornwall Memorial Scholarship.

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