‘N-MNYS_5_WG_CLOSE’ constraint set invoked, because of unplanned outage of Yass – Marulan 5 330kV line
At 16:16 (NEM time) on Wednesday 10th December 2025 there was an unplanned outage of Yass - Marulan 5 330kV line.
Eventful days in 2025
A catalogue of articles pertaining to eventful days in 2025
Yo-yo-ing of ‘Market Demand’ in South Australia – on Wednesday 10th December 2025
Whilst today saw the release of the draft 2026 ISP, some 'challenges of the future' are already here today - such as the increasingly large and common gyrations in 'Market Demand' seen in South...
Another example of (presumably VRE-induced) weakness in mainland frequency – Wednesday afternoon 10th December 2025
We can see that the frequency weakened late in the afternoon (Wednesday 10th December 2025), falling down towards the Normal Operating Frequency Band.
Victorian Auditor-General’s report ‘Managing the Transition to Renewable Energy’
We thought it might be useful to point directly to the 61-page report ‘Managing the Transition to Renewable Energy’ by the Victorian Auditor-General.
AEMO releases draft of 2026 ISP
Today (Wednesday 10th December 2025) the AEMO has released the much-awaited* draft of the (upcoming 2026 iteration of the) Integrated System Plan .
Wellington North Solar Farm back to 94 ELAV compared to 104 in total
Third article in the series, we take a look at the specifics of how much of Wellington North Solar Farm is back online (at Tuesday morning 9th December 2025).
Early morning price volatility in South Australia on Monday 8th December 2025
There was some early morning price volatility in South Australia on Monday 8th December 2025 - a social media update from Michael Caravaggio from EPRI internationally prompts this article.
Wellington North Solar Farm back online (late Sunday afternoon 7th December and) Monday 8th December 2025
The Wellington North Solar Farm (which came offline Sunday 7th December 2025 due to grass fire) is back online.
Wellington North Solar Farm offline in ST PASA data from Saturday 6th December 2025, following grassfire
Just after 13:00 (NEM time) on Saturday 6th December 2025, the Wellington North Solar Farm came offline following a grass fire onsite.
Lengthy unplanned outage at Yallourn unit 2 extended another 19 days – expected RTS now 12th February 2026
On Friday 5th December 2025 we also saw EnergyAustralia report to AEMO the 19-day extension to the lengthy unplanned outage at YWPS2 following 'LP turbine issues' experienced in August 2025.
Actual MSL2 in South Australia (not the first time) on Sunday 7th December 2025
At 11:02 (NEM time) on Sunday 7th December 2025 the AEMO published MN131472 noting 'Actual MSL2' in South Australia
AEMO requests that Notice of Closure be extended to 5 years (in some cases)
Flagging (from the AEMO rule change request on 14th November 2025) the request to extend Notice of Closure to 5 years ... and to remind readers of thoughts already submitted to the Nelson Review...
Worth noting the AEMO rule change request ‘Efficient and timely management of system security needs through the energy transition’
Pre-dating AEMO’s Monday release of its 2025 TPSS, was AEMO’s Rule Change Request ‘Efficient and timely management of system security needs through the energy transition’.
Increase in minimum LHS Factors in Constraint Equations gone live Tuesday 2nd December 2025
It’s also worth explicitly calling out the increase in minimum LHS factors (from 0.07 to 0.15) that also went live yesterday (Tuesday 2nd December 2025).
‘Blackout bingo’ in the media again this week … this time with Victoria and Yallourn
Following media reporting from Monday about 'blackouts' and 'Eraring closure', today (Wednesday 3rd December) there's a media report about 'blackouts' and 'Yallourn closure'
Belatedly noting v2.0 of the ‘NEM Readiness Guide’ (and Checklist) by the AER, released on 29th August 2025
I was on a call earlier and someone helpfully circulated a link to the document ‘NEM Readiness Guide v2.0’, released by the AER on 29th August 2025 - so now noting here, for ease...
Release 1 of the ISF (Improving Security Frameworks) reform went live, on Tuesday 2nd December 2025
Noting that yesterday (Tuesday 2nd December 2025) saw a milestone reached, with ‘Go Live’ achieved for Release 1 of the Improving Security Frameworks (ISF) reforms.
AEMO declares Scheduling Error – related to the ‘Self-forecast vendor issue’ experienced on 19th August 2025
Last week (on Thursday 27th November) the AEMO made a Scheduling Error Declaration about the sizeable glitch in a particular self-forecast vendor that delivered phantom production on Tuesday 19th August 2025 and a large...
AEMO updated MT PASA guidance, on 2nd December 2025
At 13:55 on Tuesday 2nd December 2025, the AEMO published MN131337 as an update earlier MT PASA updates (continuing to forecast Low Reserve Condition for NSW for periods between August 2027 to November 2027).
How collective under-performance of Semi-Scheduled Solar Farms weakened frequency on Sunday afternoon 30th November 2025
We’ve already posted about how ‘Mainland Frequency dragged downwards around sunset, on Sunday 30th November 2025’. Here, we see how underperformance across Large Solar Farms was a major cause.