Run of extreme prices in the SA region on Friday 8th December 2023

Prices in South Australia have been hovering close to the market cap for several dispatch intervals, with prices still elevated at the time of writing. The initial price spike came in the late morning when the ENERGY price jumped from $0.00 to $16,490.50 for the 10:55 dispatch interval.

Elevated price outcomes and forecasts for SA as at the time of writing (11:45 NEM time).

Source: ez2view’s Forecast Convergence widget


At 10:50am NEM time, the AEMO issued Market Notice 112074 (shown below) which noted the invocation of the ‘I-VS_250’ constraint set due to the “existence of widespread abnormal conditions namely severe weather”.



Notice ID 112074
Notice Type ID Reclassify contingency events
Notice Type Description MARKET
Issue Date Friday, December 8, 2023
External Reference Reclassification of non-credible contingency event due to existence of widespread abnormal conditions – SA region.


AEMO has identified that a non-credible contingency event impacting the power system is more likely to occur and is considered reasonably possible because of the existence of widespread abnormal conditions namely severe weather in the SA region.

AEMO has therefore reclassified the occurrence of a non-credible contingency event involving multiple plant due to these abnormal conditions as credible.

AEMO has taken the following action to maintain power system security at 1050 hrs 08/12/2023.
Constraint set invoked: I-VS_250

Duration: 1050 hrs 08/12/2023. until further notice

Need for further measures is being monitored and further measures may be implemented in line with the Power System Security Guidelines (SO_OP_3715).

Manager NEM Real Time Operations


The ‘I-VS_250’ constraint set contains two constraint equations which both relate to the upper transfer limit on the Heywood interconnector.

The I-VS_250 constraint set was invoked from the 10:55 dispatch interval (screenshot taken during this interval).

Source: ez2view’s Constraint Set Details widget


As for the ‘extreme weather’ noted in the market notice above – a quick glance at my usual weather apps show thunderstorms and elevated temperatures in parts of the state. The screenshot below has been taken from Windy and focuses on the south-east of the state.

Thunderstorm coverage and temperature readings for south-east SA as of approximately 11am (NEM time)

Source: Windy

The ABC is also reporting of widespread bushfire danger in parts of the state:

“The Bureau of Meteorology has also issued a severe weather warning for damaging winds with peak gusts of 90 to 100 km/h in those areas of elevated fire risk from late morning, while thunderstorms will likely bring damaging gusts during the afternoon as well.”

About the Author

Dan Lee
Dan Lee first started at Global-Roam in June 2013. He has departed (and returned) for a couple of stints overseas in that time, but rejoined our team permanently in late 2019. More recently, Dan's focus has been on growing his understanding of the market and developing his analytical capabilities. He is currently enrolled in the Master of Sustainable Energy program at the University of Queensland.

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