SA1 experienced very high renewable penetration of 92.8% during the early morning period of 7 September 2026, driven predominantly by wind generation (635.54 MW) and solar generation (448–461 MW). Negative and near-zero spot prices (ranging from −$4.32/MWh to $0/MWh) resulted from the substantial surplus of renewable energy supply relative to regional demand.
The high renewable output combined with typically low overnight and early-morning demand created excess supply conditions that suppressed prices into negative territory. Binding constraints F_T+LREG_0050 and F_T+RREG_0050, with marginal values of approximately $21.38–$21.95/MWh and $3.45/MWh respectively, indicate that transmission or reserve regulation limits were active during this period, constraining the market's ability to freely export surplus renewable generation and preventing prices from falling further below zero.
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.