South Australia (SA1) experienced 91% renewable penetration during the settlement period ending 31 August 2026 at 00:00, driven by high wind generation (670.6 MW) and combined solar output (708.2 MW) against modest gas-fired generation. Prices collapsed to $0/MWh at 00:00, then recovered to $14.19/MWh by 00:05, indicating a brief oversupply condition followed by rapid rebalancing.
The zero price at 00:00 reflects excess renewable supply relative to demand and system capability to absorb or export the output. Multiple binding constraints with elevated marginal values (T_BLINK_TV_NGZ at $8.35M/MW, F_T+LREG_0050 at $16.69/MW, F_T+RREG_0050 at $5.39–5.03/MW, F_MAIN+RREG_0220 at $5/MW) suggest system limitations on ramping, regulation, or interconnector flows prevented further dispatch and forced price suppression. The rapid price recovery within five minutes indicates the constraint binding was temporary and alleviating mechanisms (demand response, export capacity availability, or generation adjustment) quickly restored equilibrium.
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.