South Australia (SA1) experienced very high renewable penetration of 95.0% during the early morning period of 3 September 2026, driven primarily by wind generation (636 MW) and solar output (439 MW combined). This high renewable contribution resulted in negative regional reference prices ranging from −$20.00/MWh to −$7.00/MWh across the six consecutive five-minute settlement periods.
The negative pricing reflects an oversupply of renewable generation relative to local demand, a characteristic pattern during periods of high wind and solar output when dispatchable generation cannot be economically reduced further. The binding constraints—particularly those with high marginal values such as F_T+RREG_0050 (139.26 and 31.93) and F_T++NIL_ML_L6 (43.80)—indicate that network or system security limitations were active in constraining available dispatch capacity, preventing further export of excess generation and thereby driving prices negative to incentivise consumption and curtailment.
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.