Out of cycle MTPASA update identifies low reserves in VIC

An out of cycle MTPASA run published 8th Jan 2025 identifies low reserve conditions (LRC) in VIC for January to March 2025.

Market Notice #122979 captures the LRC declaration best:

122979 RESERVE NOTICE 08/01/2025 06:38:46 PM

RESERVE NOTICE MT PASA 8 January 2025

AEMO published an out-of-cycle MT PASA run on 8 January 2025 in response to updated MT PASA offers that included additional outages that materially affect the MT PASA outcomes. The result identifies annual unserved energy exceeds the Reliability Standard between:
-- January 2025 - January 2026 in Victoria.

AEMO declares Low Reserve Conditions (LRC) as per clause 4.8.4 of the National Electricity Rules (NER) for:
-- January 2025 - March 2025 in Victoria when forecast demand exceeds supply under some circumstances.

Reliability risks in New South Wales are forecast to exceed the Reliability Standard during January 2025 - January 2026, but they are impacted by transmission outages and reclassifications. As these outages and reclassifications are not considered as part of a reliability incident as per clause 3.9.3C of the NER, AEMO is not declaring LRC for New South Wales at this time.

MT PASA provides early information to the market on potential reliability issues, enabling the market to respond proactively and potentially avoid the need for AEMO intervention.

For further information, please refer to:
https://www.aemo.com.au/Electricity/National-Electricity-Market-NEM/Data/Market-Management-System-MMS/Projected-Assessment-of-System-Adequacy

This notice supersedes Market Notice 122923 published on 7 January 2025.

Background

As part of a broader process of implementing the reliability standard, AEMO runs the Medium Term Projected Assessment of System Adequacy (MTPASA) process weekly to forecast expected unserved energy levels over a two year period. If the expected annual unserved energy exceeds the maximum level specified by the Reliability Standard, a Low Reserve Condition is identified.

For more information about how AEMO implements the reliability standard, please view the Reliability Standard Implementation Guidelines (RSIG) available on AEMO's website at https://www.aemo.com.au/Electricity/National

Forecasting

AEMO

(bold added for emphasis)

MTPASA information highlights the driver of the declaration

Using the PASA widget in ez2view, and time-travelled to the 8^th Jan (when the latest MTPASA run was available), we can see the change in weighted annual unserved energy for the year to 12 Jan 2026. The key change is in the hover-over box which shows the weighted unserved energy (USE)  projection was to exceed the reliability threshold of 0.002. In accordance with the procedure this raises a Low Reserve Condition (LRC=1).

January to March

To understand how January to March 2025 came to be the key LRC months in the market notice we inspect the monthly MTPASA results.

Again using the PASA widget, we can see the LRC months as January to March (interval dates are month-ending), because LRC = 1. The precision of the USE Weighted Avg column is a bit short so we don’t always get to see the weighted averages being greater than 0.002.

An interesting aspect is that only the month of January changed in weighted USE (materially, 34%). I presume this must have been enough to tip the annual USE measure over the threshold.

Supply side drivers

For this the MTPASA DUID Availability widget provides us answers (upon careful selection of the availability runs aiming to match them up to the set used as input into the relevant MTPASA runs). Note, I’ve filtered to coal units in VIC to better-capture the changes.

We can see:

• Loy Yang A Unit 4 has reduced availability. Inspecting the generator outages widget, the unit is citing unplanned forced deratings as the reason.
• Yallourn West Unit 4 has extended its outage for four more days.

These outages are having a net reduction in scheduled availability ranging from 6 to 8% of VIC coal fleet availability (260-360 MW) relative to the previous run. This is 4% relative to a previous total VIC scheduled availability (around 9100 MW).