SA1 experienced very high renewable penetration of 91.3% during the 11:05–11:30 period on 12 September 2026, driven predominantly by wind generation (913 MW) with support from battery discharge (321 MW combined). Regional spot prices exhibited high volatility, ranging from –0.03 to 35.93 $/MWh, with a notable negative price excursion at 11:20.
The high renewable penetration and price volatility were likely driven by the binding constraint F_T+RREG_0050 with a consistent marginal value of 4 $/MWh, which operated across all five settlement intervals. This constraint's repeated activation suggests a physical or operational limitation was actively constraining the dispatch; the low marginal value relative to observed price spikes indicates the constraint was not the primary price setter but rather a secondary limiting factor. The negative price at 11:20 and subsequent price recovery suggest rapid changes in system balance, potentially reflecting the instantaneous demand–supply mismatch created by the high wind generation combined with the constraint's limiting effect on flexible 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.