The WEM in Western Australia experienced a moderate price spike to $261.13/MWh in the 13:35 trading interval on 22 August 2026, representing a sharp increase from the preceding $146–151/MWh range. This single-interval spike occurred within a generation mix dominated by gas-fired plant (1,290 MW combined CCGT and OCGT) alongside substantial wind generation (353 MW).
The price spike was driven by a binding constraint (F_T+RREG_0050) with a marginal value of $4.34, indicating that this constraint became active and elevated the spot price above the unconstrained thermal dispatch level. The constraint's binding status during an interval of elevated gas-generation dependency and following a period of stable pricing at ~$147–149/MWh suggests either a sudden demand spike, a generation loss, or the activation of a network or reserve constraint that forced more expensive generation into service or restricted lower-cost plant dispatch.
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.