South Australia (SA1) experienced high renewable penetration of 91% during the evening of 22 September 2026, with wind generation dominating at 821.71 MW alongside substantial solar output. Negative prices emerged across multiple settlement intervals (ranging from −$7/MWh to −$4.01/MWh), indicating oversupply relative to demand.
The negative pricing and high renewable penetration were driven by strong wind and solar generation exceeding regional demand during evening hours. Multiple binding constraints with material marginal values—particularly F_TASCAP_RREG_0220 (ranging from $3.45–$7.79/MWh) and F_T+RREG_0050 ($4.99/MWh)—indicate that export or regional stability constraints were active, limiting the ability to export excess renewable generation and forcing local dispatch to operate at negative prices to maintain 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.