SA1 experienced sustained negative pricing at −$3.34/MWh during the 23:15 interval on 28 August 2026, with negative pricing persisting across 2 consecutive intervals. Prices recovered to positive territory both before and after this period, indicating a localised, transient event rather than systemic stress.
The generation mix showed high renewable penetration (wind 382.99 MW, solar 269.78 MW) combined with dispatchable gas capacity (146.8 MW OCGT, 104.82 MW CCGT), which typically supports pricing stability. However, multiple binding constraints with marginal values of $3.54–$4.99/MWh indicate transmission or reserve requirement limitations that prevented efficient dispatch of excess generation, forcing generators to pay down (accept negative prices) to continue operation. The rapid price recovery in surrounding intervals suggests the constraint bind was temporary rather than indicating sustained oversupply.
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.