SA1 experienced sustained negative pricing across three intervals on 5 September 2026 around midnight, with prices ranging from −$4.51/MWh to −$6.14/MWh. The negative pricing occurred during a period of high renewable generation, particularly wind at 1378 MW, combined with moderate solar and gas generation.
The negative pricing reflects oversupply conditions typical of high-wind periods with constrained demand absorption capacity. Binding constraints with marginal values between $4.44/MWh and $4.99/MWh indicate that dispatch was limited by transmission or network constraints rather than generator cost recovery, forcing marginal generation to accept negative prices to maintain system balance.
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.