VIC1 experienced sustained negative pricing over three intervals (21:50–22:15 on 31 August 2026), with prices declining to a minimum of –$6/MWh. The event occurred during a period of high renewable generation, with combined wind output exceeding 6,800 MW and solar contributing over 600 MW, whilst brown coal generation remained substantial at approximately 3,000 MW.
Negative pricing resulted from an excess supply condition where must-run synchronous generation (brown coal) and high renewable output could not be economically absorbed by demand and network constraints. The binding constraint F_T+LREG_0050 exhibited marginal values ranging from $71.25/MWh to $232,000/MWh across intervals, indicating severe binding constraint activity that likely restricted interregional flows or network capability, preventing efficient dispatch of surplus generation and forcing the market into an oversupply regime. The concurrent binding of constraint F_TASCAP_RREG_0220 with a marginal value of $6.99/MWh suggests additional regional network limitations compounded the supply–demand imbalance.
Causal analysis generated by gridIQ's synthesis model from live AEMO market data: dispatch prices, generation mix, interconnector flows and market notices in the interval surrounding the event.