WEM prices in WA1 spiked sharply to $260.88/MWh at 16:20 on 27 July 2026, representing a 52% increase from the prior five-minute interval and a 154% surge from baseline prices two intervals earlier. The spike was concentrated in a single trading interval with prices elevated across the preceding 15 minutes, suggesting a transient constraint-driven event.
The binding constraint F_T+LREG_0050 held marginal values ranging from $5.61–$7.15/MWh during this period, indicating it became increasingly binding as the price spike developed. The generation mix was dominated by coal (923 MW) and gas thermal plant (1,125 MW combined OCGT and CCGT), with substantial battery discharge (604 MW), while wind and solar contributed only 561 MW combined—suggesting tight left-over capacity or transmission headroom under the active constraint as the system approached the congestion threshold.
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.