VIC1 experienced negative pricing at $–0.56/MWh across two intervals (22:25 and 22:30) on 17 September 2026, with a minimum price of $–0.56/MWh sustained over the 2-interval period. The region's generation mix was dominated by wind (2,382 MW) and brown coal (2,807 MW), alongside substantial solar output (1,195 MW), creating an oversupply condition during low-demand evening hours.
Negative pricing in VIC1 was driven by an excess of available generation relative to demand, with high renewable output (wind and solar totalling 3,577 MW) combining with inflexible brown coal generation to create downward price pressure. The binding constraints—particularly F_T+LREG_0050 with a marginal value of $12.70 and F_T+RREG_0050 with marginal values of $3.73—indicate that regulation service requirements were constraining dispatch flexibility, preventing efficient load-following and amplifying the oversupply condition that forced marginal generators to accept negative prices to remain dispatched.
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.