South Australia (SA1) experienced sustained negative pricing between 03:55 and 04:30 on 10 August 2026, with prices ranging from −$7.01 to −$11.68/MWh across 3 intervals. The region had high renewable generation (1,376.61 MW wind, 90–113 MW solar) and modest battery and gas-fired generation, creating an oversupply condition.
Negative pricing resulted from excess renewable generation relative to regional demand and export capacity. The binding constraint NSA_Q_GSTONE34_250 held consistently high marginal values (ranging from $31.69 to $73.82/MWh), indicating it was actively restricting regional power flows and preventing sufficient export of surplus generation, thereby forcing the residual supply-demand imbalance to clear at negative prices.
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.