South Australia (SA1) experienced two consecutive intervals of negative pricing at -$1/MWh on 1 June 2026 at 23:20 and 23:25, representing a minor market event. This occurred during an evening period when wind generation dominated the mix at approximately 1,843 MW, accompanied by significant solar (74.49 MW combined) and battery storage (112.99 MW combined) output.
The negative pricing was likely driven by oversupply conditions created by high wind generation (1,843 MW) combined with concurrent solar output during the evening transition period, where demand typically begins declining. The region's binding constraints (F_MAIN+RREG_0220 and F_T+NIL_MG_RECL_R6) suggest transmission limitations were active, forcing the market to accept negative prices to manage excess renewable generation that could not be exported efficiently, a common occurrence when instantaneous generation exceeds both local demand and available export capacity through constrained transmission paths.
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.