Sky-high IRPM in the middle of the day, Sunday 1st October 2023

Finally finding a bit of time to crunch some numbers for the GenInsights Quarterly Update for 2023 Q4* and I’m looking particularly how NEM-wide IRPM has performed across the Quarter, and trended over the longer term as well.  This is part of what’s collated in Appendix 1 for 2023 Q4.

* yep, we’re starting this process much later than we had hoped!

Those unfamiliar with Instantaneous Reserve Plant Margin as a measure of the balance between supply and demand should note that:

1)  High percentages indicate plenty of surplus across the NEM … which should mean quite low (increasingly negative) prices; whereas

2)  Lower percentages mean tight supply-demand balance, and hence likely to be high prices across most (if not all) regions.

(a)  A general rule of thumb is that under 15% provides a good chance of volatility across multiple regions.

… some specific articles referencing ‘low IRPM’ are tagged here.

(b)  In these Quarterly Updates we take a look at instances under 20%.


In this brief Case Study I’m just going to post this snapshot focused on a trend of IRPM across the day on Sunday 1st October 2023 (i.e. first day in Q4), with the days either side included for a bit more context.


This chart has been produced in NEMreview v7 … clients with a licence to the software can open their copy of this query here.

The highest point in the day (274.4% at 12:05 NEM time ) is an extremely high level … refer the GenInsights Quarterly Update for 2023 Q4 for more context.

About the Author

Paul McArdle
One of three founders of Global-Roam back in 2000, Paul has been CEO of the company since that time. As an author on WattClarity, Paul's focus has been to help make the electricity market more understandable.

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