The WEM experienced a moderate price spike in WA1 on 19 August 2026, with the regional reference price (RRP) jumping from $149.91/MWh to $276/MWh and $276.54/MWh across two consecutive 5-minute trading intervals. This represented an 84% increase in price over a single interval, before prices stabilised at elevated levels.
The binding constraint F_T+RREG_0050 with marginal values of approximately $4.26/MWh was active during the spike, indicating this constraint was the primary driver of the price elevation. The generation mix at the time showed substantial gas-fired generation (894.2 MW OCGT and 571.33 MW CCGT), alongside significant battery output (499.48 MW), but the binding constraint's persistent activation suggests supply-demand tightness in a specific operational area that drove the market to bid up prices to clear the constrained region.
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.