South Australia (SA1) experienced high renewable penetration of 97.7% on 11 July 2026, driven predominantly by wind generation of 1769 MW with minimal solar and battery contributions. This high renewable penetration coincided with negative regional reference prices (RRP) ranging from −1.05 to −1.20 $/MWh across the settlement intervals.
The negative pricing reflects excess renewable generation relative to demand, a common outcome when wind output is high and solar is unavailable (evening period). The binding constraint F_T+RREG_0050, with marginal values between 3.05 and 4.05 $/MWh, indicates an active operational limit that is constraining dispatch and contributing to the marginal cost floor driving negative prices when renewable supply exceeds constrained export or local demand capacity.
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.