SA1 experienced sustained negative pricing during the early morning period of 18 June 2026, with prices reaching −$20/MWh across three intervals and averaging −$4/MWh over the two-interval window specified. The region maintained elevated renewable generation, particularly wind at 1176.51 MW and solar at approximately 169 MW, alongside moderate gas-fired generation.
The negative pricing was driven by an excess of inflexible renewable generation relative to local demand during the low-demand early morning period, with wind and solar output totalling over 1500 MW constrained against modest dispatchable capacity. Multiple binding constraints with marginal values ranging from $3.75 to $6.80/MWh indicate that network or system constraints restricted the ability to export excess generation, forcing the price mechanism to incentivise load increase and generation reduction to restore balance.
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.