South Australia (SA1) experienced sustained negative pricing at −$6.25/MWh during the 18:50 interval on 24 August 2026, followed by a partial recovery to −$1.28/MWh in the subsequent interval. This represents a sharp deviation from the preceding positive prices of approximately $9/MWh. The negative pricing occurred during a period of high wind generation (1,646 MW) with minimal solar and battery output, suggesting oversupply conditions in the region.
The negative pricing was driven by binding constraints with material marginal values, most prominently constraint F_TASCAP_RREG_0220 at $5.49/MWh and constraint F_T+RREG_0050 at $4.28/MWh, indicating physical transmission limitations were active in managing power flows. The combination of high wind generation relative to demand, coupled with these binding constraint costs, created a situation where marginal generation pricing turned negative as the market required downward economic signals to manage supply-demand balance within the active constraint envelope.
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.