SA1 experienced sustained negative pricing on 19 September 2026 from 21:05 to 21:25, with prices declining to a minimum of −$49.98/MWh over three intervals. The region's generation mix was heavily weighted towards wind (822.52 MW) and battery (76.16 MW combined), with minimal gas generation, creating oversupply conditions during this period.
The negative pricing was driven by high renewable generation relative to demand, particularly elevated wind output that exceeded consumption requirements. A binding constraint (F_T+LREG_0050) with marginal values ranging from $15.99 to $40.99/MWh constrained dispatch flexibility, preventing generators from being economically backed off and forcing continued output into an oversupplied market, thereby pushing prices negative as dispatchable generation became redundant.
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.