SA1 experienced sustained negative pricing of approximately −$1/MWh across 2 intervals (00:50 and 00:55) on 12 August 2026, representing a minor pricing anomaly in an otherwise low-price period. Prices declined progressively from $16.76/MWh at 00:20 to the negative territory, with a sharp drop occurring between 00:45 and 00:50.
The negative pricing is supported by high renewable generation, particularly wind output of 1,461 MW and solar generation totalling 674 MW, which created a structural oversupply in the region. A binding constraint (NSA_Q_GSTONE34_250) with marginal values declining sharply from $23,107.70 to $47.24 and $33.23 during the negative price intervals indicates a critical transmission or network limitation that prevented efficient export or dispatch of excess renewable generation, forcing the market to pay generators to reduce output.
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.