Negative pricing of approximately −$7.69/MWh occurred in TAS1 for two consecutive intervals (23:50 and 23:55 on 9 September 2026), representing a sharp reversal from the preceding $5.10/MWh baseline. The event was minor in severity and brief in duration, with prices recovering immediately thereafter.
Tasmania's generation mix during this period was heavily weighted towards renewables, with combined wind and hydro output exceeding 1,500 MW across the region, whilst demand-side flexibility was constrained. Multiple binding constraints with notable marginal values—particularly F_TASCAP_RREG_0220 at 12.2 $/MWh and F_TASCAP_LREG_0210 at 4.66 $/MWh—indicate that dispatch flexibility or interconnector capacity limitations prevented the region from exporting surplus renewable generation, forcing AEMO to price demand downward to balance supply.
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.