South Australia (SA1) experienced very high renewable energy penetration of 94.0% during the early morning period of 9 September 2026, driven predominantly by wind generation of 1,281.91 MW. Negative Regional Reference Prices (RRPs) ranging from −$7.01 to −$7.83 per MWh occurred across the six consecutive five-minute settlement intervals, indicating surplus renewable generation that required management through pricing signals.
The negative pricing reflects oversupply conditions typical of high wind generation periods when demand is low during night-time hours. Multiple binding constraints with elevated marginal values—particularly constraint F_T+LREG_0050 (marginal value up to $17.84/MWh) and constraint F_T+RREG_0050 (marginal value $4.40/MWh)—indicate that operational limits were active in managing system stability and balancing requirements, which contributed to the suppression of spot prices into negative territory as renewable generation exceeded immediate demand.
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.