SA1 experienced sustained negative pricing across 3 consecutive intervals on 12 September 2026 at 23:05–23:15, with prices ranging from −$7.29 to −$9.38/MWh. Wind generation dominated the supply mix at 921.8 MW, whilst demand was insufficient to absorb available output even after gas and battery generation.
Negative pricing occurred because surplus renewable generation, particularly from wind resources representing over 85% of total output, could not be economically curtailed or exported. Multiple binding constraints with marginal values around $5/MWh (F_TASCAP_RREG_0220 and F_T+RREG_0050) restricted the market's ability to relieve locational or network congestion, forcing generators to pay for dispatch rather than receive revenue, and preventing inter-regional flow solutions that would otherwise have absorbed the excess generation.
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.