WA1 experienced a moderate price spike to $257.34/MWh during the 22:55 trading interval on 11 August 2026, representing a sharp increase from the $248.98/MWh recorded five minutes earlier. Prices remained elevated in the following interval at $252.50/MWh before moderating, with the spike isolated to a single interval.
The price spike was driven by binding constraints, with NSA_Q_GSTONE34_250 exhibiting the highest marginal value at approximately $29/MWh across multiple intervals, indicating a significant scarcity signal at that constraint. The combination of active binding constraints including F_T++NIL_ML_RECL_L6 and F_MAIN++RREG_0220 (with marginal values of $8.24 and $7.75/MWh respectively) suggests system-wide transmission or operational limitations that compressed available supply margins and elevated the market-clearing price in response to underlying demand and network constraints.
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.