VIC Inertia drops low, but combined VIC+SA level stays clear

Inertia levels in VIC, measured in megawatt-seconds (MWs), dropped below 17,500MWs on 12 November, 2024.

As at 14:25 NEM time, the chart of inertia in VIC was as follows:

Threshold levels exist, yet these are relative to the combined VIC + SA level of inertia.

The secure operating level and the minimum threshold levels are set by AEMO and communicated in its annual Inertia Report. The present levels, applied in this article, come from the latest report published December 2023.

• Note, the thresholds are for the combined level of inertia in VIC and SA. As AEMO notes in its 2023 inertia report “AEMO has assessed the inertia requirements and expected availability for a combined South Australia and Victoria region over a five-year outlook period”.
• The (VIC+SA) secure operating level for 2024-25 is 17,500 MWs.
• The minimum (VIC+SA) threshold level is 15,800 MWs.

While the chart above showed that the VIC level dropped below 15,800 MWs in the 08:50 dispatch interval, and reached a low point at 10:55 of 12,065 MWs, the combined levels were sufficient, relative to the thresholds.

When we view the combined VIC and SA level of inertia we see the level was close to the secure operating level, but did not breach it.

[post updated to reflect combined VIC+SA threshold levels]