SA1 experienced sustained negative pricing across three intervals on 19 September 2026 between 03:45 and 04:15, with prices reaching a trough of −$85.02/MWh at 03:55. Wind generation dominated the region at approximately 222 MW during this period, whilst battery storage was offline and demand was minimal during the early morning shoulder.
The binding constraint F_T+LREG_0050 maintained high marginal values (approximately $103.82–$103.84/MWh) throughout the episode, indicating it was actively constraining dispatch and preventing downward price adjustment. The combination of high wind output and the operational constraint created a situation where generators faced financial losses, likely because the constraint forced the regional system to accept more generation than demand required, driving prices into negative territory as generators competed to avoid financial penalties for non-compliance.
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.