South Australia (SA1) experienced very high renewable penetration of 97.6% on 12 July 2026 at approximately 14:05–14:30, driven predominantly by wind generation of 1,735 MW. This extreme renewable penetration resulted in negative electricity prices across all five settlement periods, ranging from −$4.63/MWh to −$1.07/MWh.
The negative pricing reflects a supply-demand imbalance wherein abundant wind generation exceeded local demand and available export capacity, forcing generators to accept negative prices to remain online. Multiple binding constraints with material marginal values (ranging from 3.44 to 5.49 $/MWh) indicate that network limitations or reserve requirements prevented efficient export of excess renewable energy, thereby trapping supply within the region and suppressing prices.
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.