WA1 experienced a major price spike to $308.95/MWh during the 18:10 interval on 20 July 2026, representing a 30% increase from the previous interval. Prices had been escalating across the preceding five intervals, rising from $171.45/MWh at 17:45, indicating progressively tightening market conditions.
The binding constraints F_TASCAP_RREG_0220 (marginal value $3.43/MWh) and F_T+RREG_0050 (marginal value $2.74/MWh) were active during the event, suggesting tight reserve or ramping requirements contributed to the price spike. The generation mix shows substantial reliance on gas-fired plant (1,309 MW OCGT and 332 MW CCGT) to meet demand, whilst variable renewable generation (wind and solar totalling 187 MW) was relatively modest, creating conditions where transmission or operational constraints on available generation capacity could bind, driving prices toward the cap.
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.