South Australia (SA1) experienced a moderate price spike reaching $845.11/MWh on 21 June 2026 at 13:40 UTC, with elevated pricing occurring across at least two intervals. The spike was notably volatile, with prices fluctuating sharply between $230/MWh and $845/MWh across a 30-minute period, suggesting rapid changes in dispatch conditions.
The price spike occurred despite substantial gas generation capacity online (1,631 MW combined CCGT and OCGT) and battery support (98.5 MW), indicating supply availability was not the primary constraint. Multiple binding constraints with marginal values between $4.47–$7.51/MWh were active during the event, suggesting network or system security limitations rather than fuel scarcity drove the elevated pricing. The sharp price reversals within the 30-minute window point to transient constraint activation or rapid demand/renewable variability rather than sustained supply shortfall.
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.