South Australia (SA1) experienced sustained negative pricing of −$7.14/MWh during the 21:00 settlement interval on 31 August 2026, with negative prices occurring in at least 2 intervals. The region's generation mix was dominated by wind output (1,878.52 MW) with supporting battery and gas-fired generation, creating an oversupply condition.
The negative pricing reflects a supply surplus during a period of high wind generation relative to demand, requiring the market to pay generators to reduce or reverse output. Multiple binding constraints with marginal values—including constraint F_T+LREG_0050 with values ranging from $14.81 to $74.42/MWh and F_TASCAP_RREG_0220 at $7.75/MWh—indicate active network limitations that constrained the system's ability to export excess generation or balance supply, forcing prices into negative territory to incentivise demand response or generation withdrawal.
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.