Victoria experienced two intervals of negative pricing on 20 September 2026 at 09:05 and 09:15 AEST, with a minimum price of −$4.67/MWh. The event occurred amid elevated wind and coal generation totalling approximately 10,217 MW, with prices recovering to positive territory by 09:10 before dipping negative again at 09:15.
The negative pricing was likely driven by an oversupply of generation relative to demand in Victoria during this period. With wind generation at combined capacity exceeding 7,876 MW and coal generation at 2,341 MW, the market faced significant must-run generation constraints. Multiple binding constraints, including F_T+LREG_0050 with marginal values ranging from 25.89 to 30.77, indicate that transmission and regulation service requirements actively constrained dispatch, forcing additional generation to be scheduled despite insufficient demand, thereby depressing prices below zero.
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.