The WEM experienced a sharp price spike in WA1 on 18 August 2026, with the regional reference price (RRP) surging to $308.8/MWh during the 14:50 interval—a $84.52/MWh jump from the previous five-minute settlement. This single-interval event marked a major price excursion following a sustained upward price trajectory over the preceding 25 minutes.
The binding constraint F_T+LREG_0050 was active throughout the price escalation period with marginal values ranging from $10.64 to $25.31/MWh, indicating that this operational constraint was restricting dispatch and pushing prices toward the price cap. The generation mix at the time shows substantial reliance on gas-fired generation (OCGT and CCGT totalling 1,415 MW) and battery output (629 MW), which are typically higher-cost marginal units; the combination of constrained dispatch capability and elevated marginal generation cost appears to have driven the spike to near-cap levels.
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.