VIC1 experienced sustained negative pricing at approximately −$9/MWh across two intervals (03:05–03:10) on 5 September 2026, with prices remaining negative through subsequent intervals. The negative pricing reflects an over-supply condition driven by high renewable generation (2,336–2,374 MW wind and 823 MW solar) combined with inflexible brown coal generation (2,511 MW) during a low-demand period.
The binding constraints with positive marginal values (F_T+LREG_0050 at $9.27/MWh, F_TASCAP_RREG_0220 at $5/MWh, and F_T+RREG_0050 at $3.45/MWh) indicate that dispatch flexibility was constrained by regulation service requirements and interconnector capability limits. With minimal gas and battery generation available to provide downward flexibility, and brown coal unable to ramp down quickly, the market required financial incentives (negative pricing) to induce demand response or curtailment of renewable generation to restore balance.
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.