SA1 experienced sustained negative pricing at -$0.50/MWh and -$0.31/MWh across two consecutive 5-minute intervals (02:45–02:50 on 31 August 2026), following a declining price trend from $1.69/MWh. The generation mix during this period was dominated by solar (501–508 MW) and wind (258 MW) output, totalling approximately 1,347 MW of renewable generation.
The negative pricing reflects an oversupply condition in SA1 during a period of high solar and wind generation relative to regional demand. Multiple binding constraints with substantial marginal values (ranging from 4.38 to 13.68 $/MWh) indicate that export capacity or network security limits were restricting the region's ability to dispatch surplus renewable energy, forcing the marginal price below zero to clear the excess supply. The dominance of near-zero marginal cost solar and wind generation, combined with binding export or regulation constraints, created conditions where generators were incentivised to reduce output rather than pay to export.
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.