South Australia (SA1) experienced very high renewable penetration at 97.1% during the 16:00–16:30 period on 9 June 2026, driven primarily by wind generation of 1,438.82 MW. Spot prices fell into negative territory, ranging from −$5.15 to −$3.00/MWh, reflecting the oversupply of low-marginal-cost renewable energy.
The extreme renewable penetration and negative pricing were directly caused by sustained high wind output combined with minimal solar and thermal generation, creating a structural surplus. Multiple binding constraints with marginal values between $3.76 and $7.45/MWh—notably constraint identifiers F_T+LREG_0050, F_TASCAP_RREG_0220, and F_T+RREG_0050—indicate that transmission or reserve margin limits became active during dispatch, constraining further output flexibility and locking in the negative price outcome.
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.