The WEM (WA1) experienced a sharp price spike to $257.34/MWh during the 09:35 settlement interval on 10 August 2026, representing a 58% jump from the preceding interval's $162.21/MWh. Prices remained elevated in the following two intervals ($242.36 and $257.09/MWh) before moderating, with the spike occurring as a single-interval event in an otherwise stable pricing environment.
The binding constraint F_T+RREG_0050 with marginal values ranging from $3.56 to $4.57/MWh was active during the spike period, indicating a congestion or reserve requirement constraint was driving the price elevation. The generation mix at the time, dominated by coal (842.31 MW) and gas generation (1,088.26 MW combined) alongside high wind output (703.41 MW), suggests the constraint was likely limiting available supply response capacity rather than reflecting absolute generation scarcity, given total dispatchable output exceeded 3,600 MW.
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.