South Australia (SA1) experienced sustained negative pricing in the 22:50 and 22:55 intervals on 14 September 2026, reaching a minimum of -$3.38/MWh. This followed a sharp price collapse from $7.97/MWh to near-zero levels across five consecutive 5-minute intervals, indicating a rapid shift in supply-demand balance.
High renewable generation, particularly 1,120 MW of wind output combined with 280 MW of solar generation, created substantial excess supply relative to regional demand. Binding constraint F_TASCAP_RREG_0220 with marginal values between $4.97 and $6.80/MWh indicates that system limitations in managing this supply set a floor for the region's pricing mechanism, but were insufficient to prevent negative prices as renewable output saturated the market.
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.