South Australia (SA1) experienced sustained negative pricing reaching −$2.28/MWh across two consecutive intervals (17:10–17:15 on 2 September 2026), following a period of near-zero or minimal positive pricing. The region's generation mix was dominated by wind output at approximately 1,592 MW, with marginal gas-fired and battery contributions, creating an oversupply condition.
The negative pricing was driven by a binding constraint (F_T+LREG_0050) with consistently high marginal values around $61.84/MWh across the affected and preceding intervals, indicating a persistent physical or operational restriction limiting export or load acceptance. Combined with the substantial wind generation relative to regional demand, the binding constraint forced the market to accept additional supply at negative prices rather than curtail renewable generation, resulting in the dispatch of marginal generation at negative rates to manage the constrained network situation.
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.