SA1 experienced sustained negative pricing at approximately −$7/MWh across two consecutive 5-minute intervals on 27 July 2026 at 10:30–10:35, with negative prices persisting intermittently through 11:00. The region's generation mix was dominated by wind output (1,620 MW) with minimal demand absorption from dispatchable thermal generation, resulting in oversupply conditions.
The negative pricing was driven by a structural oversupply of wind generation relative to regional demand, with insufficient flexible generation capacity available to absorb the excess supply. Multiple binding constraints with marginal values ranging from $3.65–$4.97/MWh indicate network or system security limitations were active during this period, preventing the region from exporting excess generation and forcing local price suppression to clear the market.
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.