TAS1 experienced sustained negative pricing at $-15.01/MWh across 8 consecutive intervals from 03:45 to 04:20 on 19 September 2026. The region generated approximately 480–490 MW from combined wind and hydro sources during this period, with no gas generation dispatched.
The negative pricing reflects a structural oversupply condition in TAS1 during the early morning period, driven by high renewable generation (wind ~265–271 MW and hydro ~214–220 MW) coinciding with low system demand. A binding constraint (F_T+LREG_0050) with marginal values around $103.82–103.84/MWh was active across the intervals, indicating that constraint-driven dispatch requirements forced generators to accept negative prices rather than reduce output. The binding constraint's high shadow price suggests the constraint was the primary mechanism preventing generators from being turned down, thereby creating the sustained oversupply condition that produced negative pricing.
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.