South Australia experienced sustained negative pricing with two intervals recording sub-zero rates (minimum -$3.73/MWh) on 2 September 2026 around 23:10 AEST. The event occurred during evening periods when high renewable generation (1209 MW wind, 489 MW solar) coincided with relatively low demand, creating an oversupply condition.
Negative pricing was driven by excess renewable generation exceeding local demand, with wind and solar collectively providing approximately 1700 MW of supply. Multiple binding constraints with significant marginal values (up to $40.47/MWh) indicate network or system security limitations preventing efficient export of surplus generation, forcing the market to offer negative prices to incentivise load absorption and reduce regional oversupply.
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.