Decay of mainland frequency at lunchtime on Friday 29th August 2025
As another case of frequency disruption on the mainland grid, we spotted this trend occurring just before midday on Friday 29th August 2025.
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.
Unplanned outage on Yallourn Unit 2 pushed out ~2 weeks (with new RTS Thursday 25th September 2025)
An updated look (as at 14:10 on Thu 28th Aug 2025) of expected return to service for YWPS2
Peeling the onion a little more – Solar Farm performance on Tuesday 19th August 2025, with the frequency spike to 50.2Hz
As the 5th article in an evolving series that progressively explores the (apparent self-forecasting glitch and) frequency spike on Tuesday 19th August 2025, we take an early look at Solar Farm performance.
Prices spiking again in South Australia (for Lower 1 second FCAS) on Wednesday 27th August 2025
A very short article with a snapshot from ez2view at the 11:15 dispatch interval – highlighting that Lower 1-second FCAS prices in the South Australian region are spiking (yet again!).
Notable forced outage at Yallourn Unit 2 … due to ‘LP turbine issue’
A first article about an unplanned (and potentially significant) outage at Yallourn unit 2 that began on Tuesday 26th August 2025 due to 'LP turbine issues'.
Several coal units offline (on Wednesday 27th August 2025) with unplanned outages
A short note with a snapshot of the ‘Generator Outages’ widget in ez2view (at 08:30 on Wed 27th Aug 2025) to highlight some coal units offline.
Following the 2025 ESOO, MT PASA shows forecast Low Reserve Conditions in the South Australian region (Dec 2026 to March 2027)
Following from the release of the 2025 ESOO last Thursday, the subsequent weekly MT PASA run warns of *forecast* LRC (and unserved energy) in South Australia.
The current burst of production at Tamar Valley CCGT coming to an end, on Thu 28th August 2025?
An article in the Australian by Colin Packham prompts a look in AEMO data about expectations for when Tamar Valley CCGT might be switched off.
Administered Pricing for FCAS services in South Australia ended on Sunday 24th August 2025 … so what’s next?
On Sunday 24th August 2025, Administered Pricing for FCAS in South Australia ended ... when will the ‘S-TBTU’ constraint set re-emerge?
An updated tabular list of instances of large AggROT across Semi-Scheduled units
Earlier today we trended the incidence of large Aggregate Raw Off-Target across all Semi-Scheduled units. In this updated tabulated list, we list each of the largest instances from January 2024 to June 2025.
An updated long-range trend of large instances of Aggregate Raw Off-Target (AggROT) across all Semi-Scheduled units
It's ~18 months since we took a look at the trend of large instances of Aggregate Raw Off-Target across all Semi-Scheduled units. In this article we update the analysis with data to 30th June...
Three broader questions (re)triggered by the Frequency Spike on Tuesday 19th August 2025
The (concerning) frequency spike across the NEM in the middle of the day (Tuesday 19th August 2025) has triggered many proximate questions - understandable - but also has raised these 3 Broader Questions.
AEMO releases 2025 ESOO on Thursday 21st August 2025
On Thursday 21st August 2025 (a week earlier than I'd anticipated) the AEMO has released its 2025 ESOO.
AGL considering State Government request to keep Torrens Island open for two more years
Amongst the news articles this morning that are energy related was one noting a possible delay to the closure of Torrens Island. We take a quick look...
A ~50-day view of rising spurts of volatility in the LOWER1SEC FCAS market in South Australia
With Administered Pricing in South Australia ongoing today, we take a longer-term look (across the past ~50 days) in the escalating pressure on Cumulative Price for LOWER1SEC FCAS in South Australia.
Network outage on Tailem Bend – Tungkillo 275kV line ended Tue 19th Aug, but Administered Pricing Continues into Wed 20th Aug (part 3)
Part 3 in an evolving series of articles about a series of the network outage(s) on the Tailem Bend - Tungkillo 275kV line that's driven LOWER1SEC prices through the roof and triggered Administered Pricing...
Part 2 with respect to Administered Pricing for Lower 1 second FCAS (and 9 other services) in South Australia
With Administered Pricing of all 10 x FCAS products in South Australia continuing into Monday 18th August 2025 (no surprise there), we take a second look.
The ‘2025 Victorian Transmission Plan’ released on Sunday 17th August 2025
On the weekend we noticed the release of the 2025 Victorian Transmission Plan, and thought it worth flagging here.
New ‘lowest ever’ point for ‘Market Demand’ in Queensland, on Sunday 17th August 2025
Another quick article for Sunday 17th August 2025 – this one noting a new 'lowest ever*' point for 'Market Demand' in Queensland, just shaving prior record from a year ago.
Administered pricing for FCAS in South Australia from 05:20 on Sunday 17th August 2025 (part 1)
AEMO notes that 'it has determined that an administered price period will commence at the trading interval starting 0520 on 17 August 2025' for FCAS in South Australia. We take a quick look...