VIC1 experienced sustained negative pricing on 11 September 2026 at 21:55 and 22:05 (two intervals), reaching a minimum of -$0.55/MWh. The event occurred during evening peak demand with high renewable generation (1,514 MW wind and solar combined) and substantial brown coal output (3,494 MW), creating an oversupply condition.
The negative pricing was driven by a binding constraint (I_CTRL_ISSUE_BL) with a consistently high marginal value of $26.912M across the affected intervals, indicating significant economic pressure to reduce generation dispatch. The combination of high renewable output during a period of constrained network capability, alongside inflexible brown coal generation, likely created a situation where prices were forced negative to manage excess supply and satisfy operational constraints.
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.