South Australia (SA1) experienced very high renewable energy penetration of 94.7% during the 21:35–22:00 period on 15 September 2026, driven predominantly by wind generation (1,286.87 MW) and solar output (242.33 MW combined), with minimal thermal generation. Regional reference prices remained moderate, ranging from $43.03 to $45.15/MWh, reflecting the low marginal cost of renewable supply.
The high renewable penetration was supported by strong wind conditions and evening solar availability, with battery storage (65.63 MW combined) providing flexible supply. Binding constraints with positive marginal values indicate that system security limits, rather than fuel cost, were setting the local price at certain intervals, with constraint F_TASCAP_RREG_0220 reaching a marginal value of $7.79/MWh and F_T+RREG_0050 reaching $4.79/MWh, suggesting transmission or ramping limitations were active in managing the high renewable output.
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.