VIC1 experienced sustained negative pricing at approximately –$1/MWh to –$5/MWh across seven consecutive 5-minute intervals on 11 July 2026 from 17:45 to 18:15 AEST. The negative prices were driven by high renewable generation (wind contributing ~3250–3342 MW) combined with inflexible brown coal baseload generation (3063 MW), creating oversupply conditions.
The binding constraint F_TASCAP_RREG_0220 was active during the event with marginal values ranging from $3.37 to $5/MWh, indicating supply-demand imbalance was constrained by this mechanism. The generation mix—dominated by non-dispatchable wind output exceeding 3200 MW alongside committed brown coal generation—created a situation where incremental supply had to be pushed below zero cost to maintain system balance and respect the binding constraint requirements.
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.