TAS1 experienced sustained negative pricing at −$0.59/MWh for two consecutive 5-minute intervals (22:25–22:30 on 17 September 2026), representing a minor pricing anomaly. Prices recovered to positive territory in surrounding intervals, with the broader half-hour profile showing mostly low positive prices around $0.01–$0.75/MWh.
The negative pricing coincided with high renewable generation from hydro (624.86 MW) and wind (433.02 MW) resources totalling approximately 1,058 MW during the affected period. Binding constraints with positive marginal values—including F_T+LREG_0050 ($12.70/MWh) and F_T+RREG_0050 ($3.73/MWh)—suggest physical network or operational limits were constraining dispatch, forcing marginal generators into negative price territory to manage excess renewable supply and maintain system security.
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.