SA1 experienced sustained negative pricing at -$1/MWh across two consecutive 5-minute intervals (14:15 and 14:20 on 31 August 2026), representing a minor pricing event. This followed a period of declining positive prices and occurred during a period of high wind generation (approximately 1,370 MW) with minimal solar output.
The negative pricing was driven by binding constraints with marginal values (F_TASCAP_RREG_0220 at $7.79 and F_T+RREG_0050 at $5.38), indicating that constraint-binding outcomes forced the market to require generation to be reduced below economic levels. The high wind generation combined with low demand and the inability to export surplus energy due to binding constraint conditions likely necessitated negative pricing to incentivise load or curtail supply, rather than relying on minimum generation costs.
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.