South Australia (SA1) experienced minor negative pricing with spot prices falling to approximately −$0.10/MWh across two consecutive intervals (19:50 and 19:55 on 3 June 2026). This occurred during an evening period dominated by substantial wind generation of ~1,714 MW, which appears to have exceeded local demand requirements.
The negative pricing was primarily driven by excess renewable generation, particularly from wind, which represented the dominant fuel source in the generation mix during the affected intervals. Binding congestion constraints on the Tasmanian-South Australian transfer (F_TASCAP_RREG_0220) with marginal values of 7.77 and 7.42 $/MWh likely restricted the export of excess wind energy out of SA1, forcing local generators to accept negative prices rather than curtail generation, thereby pushing the region into an oversupply condition typical of high wind, low-demand evening periods.
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.