SA1 experienced sustained negative pricing at approximately −$4.50/MWh across three consecutive intervals (12:50–13:00 on 28 July 2026), with prices falling sharply from $0.43/MWh in the preceding intervals. This minor severity event reflects a brief period of surplus generation relative to demand that required payment to reduce output.
High wind generation (1,674 MW) combined with minimal solar and battery discharge created an oversupply condition that marginal generators could not fully absorb without constraint relief. Multiple binding constraints—including one with a marginal value exceeding $8.3 million—indicate that interconnector or network limitations prevented efficient export or load shifting, forcing the region to price down to incentivise consumption reduction and generator withdrawal rather than manage supply through inter-regional transfers.
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.