South Australia (SA1) experienced sustained negative pricing, reaching a floor of −$7.01/MWh across two consecutive settlement intervals on 12 July 2026 at 05:50–05:55. The region had elevated renewable generation (wind at ~1,471 MW and solar at ~110–114 MW) coinciding with low demand typical of early morning hours, creating a supply surplus that required payment to absorb.
The negative pricing was driven by structural oversupply: high wind output combined with moderate solar generation during low early-morning demand, with minimal gas generation (0.11–43 MW across OCGT and CCGT) unable to flex down sufficiently to balance the system. A binding constraint (F_TASCAP_RREG_0220) with marginal values of 5.5–8.55 $/MWh was active across all intervals, indicating a network or reserve limitation that prevented efficient dispatch of excess renewable energy, forcing the market into negative territory to incentivise load or curtailment.
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.