Mainland Frequency dragged downwards around sunset, on Sunday 30th November 2025
This late afternoon weakness in system frequency (on Sunday 30th November 2025) seems noteworthy.
Articles by 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.
AEMO releases ‘2025 Transition Plan for System Security’
On Monday 1st December 2025 (after it was flagged in some media articles) the AEMO released its 154-page '2025 Transition Plan for System Security'.
AFR headline ‘AEMO warns of NSW blackouts if Eraring closes in 2027’ attracts attention
I’ve been away for the past week and am not back at work yet, but seeing the headline ‘AEMO warns of NSW blackouts if Eraring closes in 2027’ by Angela MacDonald-Smith in the AFR...
Further thoughts (and questions) about Waratah BESS, two weeks after the snowball started to roll…
Identifying 5 distinct time periods (from 26th Sept 2025 to 21st Nov 2025) with Waratah BESS, we take ez2view and some external references to try to piece together sequence of events in 3 of...
*Several* price spikes in NSW on Friday morning 21st November 2025 (including large jump in ‘Market Demand’)
A quick article with this NEMwatch snapshot at 08:35 (NEM time) on Friday 21st November 2025 to record some volatility in NSW.
Extending the tabulated history of significant (Frequency and/or AggROT) events into 2025 Q3 and 2025 Q4
An update of earlier article (from 8th Sept 2025) comparing Frequency Excursions with instances of large AggROT across Semi-Scheduled units - for 2025 Q3 and 2025 Q4 (ytd).
Large drop in ‘Market Demand’ in South Australia on Thursday 20th November 2025
A quick note on Thursday evening 20th November 2025 to record this large size (214MW) drop in ‘Market Demand’ in the 17:50 dispatch interval NEM time this evening.
Early afternoon volatility in NSW on Thursday 20th November 2025
We’re busy focused on other things at present, so just a NEMwatch snapshot at 13:25 (NEM time) on Thursday 20th November 2025 to mark some volatility in the NSW region.
AEMC commences consultation on two Rule Change proposals, to do with Contingency FCAS
On 20 November 2025, the AEMC published one consultation paper in relation to two Rule Change Proposals relating to contingency FCAS (size, and cost allocation).
AEMO issues Market Notice ‘Update to Negative Settlement Residue constraint equations’
On Wednesday 19th November 2025, the AEMO issued MN130792 at 15:36 about "Update to Negative Settlement Residue constraint equations"
How high did frequency get, on Tuesday 11th November 2025, when that gremlin re-appeared?
Extracted our high(er) speed readings highlights that the mainland frequency exceeded the NOFB for a period of the morning on Tuesday 11th November 2025.
The bottom falls out of SA ‘Market Demand’ unexpectedly, on Tuesday 18th November 2025
A brief record of some challenges encountered in forecasting midday Market Demand for South Australia on Tuesday 18th November 2025.
Drops in mainland frequency on Saturday afternoon 15th November 2025
I’m not sure if related to the severe weather warnings for both QLD and NSW today, but here’s a quick record of some afternoon weakness in frequency control on Saturday 15th November 2025.
(A first?) Severe Weather alert for the Queensland (and now NSW) Region … Saturday 15th November 2025
Relatively early in the afternoon (Saturday 15th November 2025) I received simultaneous alerts from the BOM and from AEMO about 'severe weather' in relation to Queensland this afternoon.
Expected RTS for Yallourn 2 slips a month – now offline until 24th January 2026
On Friday 14th November 2025, the expected return to service for YWPS2 was pushed back another ~6 weeks (now offline till Monday 24th January 2026).
AEMO frequency monitoring report provides some details of frequency event (due to self-forecast glitch) on 19th August 2025
Adding to the list of articles we've collated about the frequency disturbance on Tuesday 19th August 2025, we're copying in what AEMO published in its 2025 Q3 monitoring report about the glitch.
AEMO publishes report: ‘Frequency Monitoring–2025 Q3’
On or before 13th November 2025, the AEMO published its ‘Frequency Monitoring – Quarter 3 2025’ report:
Trying to understand the errors in ‘Initial Supply’ (on Tue 11th and Thu 6th November) as the source of the gremlins
In this article we take another step in trying to understand the source of the gremlins (on Thu 6th Nov 2025 and Tue 11th Nov 2025) that seemed to infect the dispatch process -...
How often have we seen these gremlins, injecting ‘phantom’ demand and driving frequency high? … a 1st pass
Following two instances of apparent data glitches (injecting 'phantom demand' and) driving frequency high, here's a collation of some other times (we've written about) where similar has happened.
AEMO (and the BOM) warning about possible ‘Severe Space Weather’ (at G4, possible G5) in next ~24 hours
One WattClarity reader has pointed us to AEMO and BOM warnings about space weather - noting that 'G4 geomagnetic storm conditions are currently being observed. G4 with a chance for G5 is expected on...