The WEM experienced a moderate price spike in WA1, reaching $257.34/MWh at 09:30 on 20 July 2026, representing a $7.74/MWh increase from the previous interval. Prices had been escalating over the preceding 25 minutes, rising from $166.67/MWh to near $250/MWh before the spike.
The binding constraint F_T+RREG_0050 was active throughout the period with marginal values ranging from $2.74–$3.74/MWh, indicating this constraint was a price-setter and contributed to the elevated pricing. The generation mix shows substantial reliance on gas-fired generation (1,639 MW combined CCGT and OCGT) alongside battery output (510 MW), suggesting tight supply conditions where marginal fossil fuel and battery generation were required to meet demand, resulting in progressively higher dispatch costs during the spike period.
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.