TAS1 experienced sustained negative pricing across 3 intervals on 4 September 2026, with prices reaching −$5.42/MWh at 17:40. The region generated substantial renewable output (hydro and wind totalling 468–712 MW across observed periods) concurrent with OCGT generation around 124 MW, creating an oversupply condition relative to local demand.
Negative pricing in TAS1 was driven by high renewable generation (particularly wind output of 158–280 MW and hydro generation of 235–290 MW) that exceeded regional demand, forcing down-regulation of dispatchable plant. The binding constraint F_TASCAP_RREG_0220, active throughout the event with marginal values of $4.97–$6.80/MWh, indicates a transmission or system limit was restricting the region's ability to export surplus generation or import alternative supply, trapping local excess generation and driving prices negative to incentivise load increase or generation reduction.
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.