SA1 experienced sustained negative pricing at approximately −$6/MWh across two intervals (16:40–16:50) on 27 July 2026, with prices reaching a minimum of −$6.37/MWh. The event occurred during a period of high wind generation (1615 MW) and low demand, with minimal solar and battery output.
The binding constraint F_T+LREG_0050 demonstrated positive marginal values (ranging from $5.81 to $7.20/MWh) throughout the pricing period, indicating the constraint was actively limiting dispatch and creating downward pressure on prices. High renewable penetration from wind generation, combined with the constraint-induced suppression of marginal generation, resulted in negative pricing as the market required financial incentives to reduce output or curtail supply.
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.