SA1 experienced sustained negative pricing at −$2–$3/MWh across five intervals during the early morning of 4 June 2026, with the lowest trough at −$3/MWh. The region was heavily supplied by renewable generation, particularly wind (1493 MW) and solar (449 MW combined), alongside battery and gas-fired capacity totalling approximately 185 MW.
The negative pricing reflects oversupply conditions typical of high renewable penetration periods, where marginal generation costs fall below zero when export or curtailment becomes necessary. Multiple binding constraints with positive marginal values—notably F_S++TBTU_R6 at $19/MWh and F_MAIN+RREG_0220 ranging from $4.99–$7.09/MWh—indicate that transmission or regional constraints actively limited the region's ability to export surplus wind and solar generation, forcing prices negative to incentivise demand-side response and battery charging.
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.