Tasmania experienced sustained negative pricing of -$9/MWh across 2 consecutive intervals (03:20 and 03:25 on 17 August 2026), representing a minor severity event. Prices declined sharply from positive levels, reaching a floor of -$9.01/MWh before recovering.
The negative pricing appears driven by binding constraints with significant marginal values, particularly F_TASCAP_RREG_0220 which exhibited marginal values ranging from 5 to 9 across the event period. The generation mix shows substantial hydro output (464–518 MW) combined with rooftop PV (166 MW) and wind (89–91 MW), creating a supply-dominated dispatch situation that required negative pricing to manage network constraints and maintain system 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.