SA1 experienced sustained negative pricing of approximately -$0.94/MWh for two consecutive intervals (15:30 and 15:35 on 19 September 2026), following a period of near-zero pricing. The negative pricing occurred despite significant wind generation of 1896.75 MW and modest battery and gas-fired generation in the region.
The negative pricing was driven by a binding constraint (F_T+LREG_0050) with marginal values in the range of 26.8–27.6 $/MWh during the affected intervals, indicating a tight physical or network limitation that forced the market to accept energy at negative prices to resolve the constraint violation. The high wind generation output combined with the constraint binding suggests that renewable generation exceeded demand and available export capacity, necessitating negative pricing to incentivise load or reduce 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.