SA1 experienced sustained negative pricing of -$4.04/MWh during the 00:20 settlement interval on 23 August 2026, following a price dip to -$1.10/MWh in the preceding interval. The negative pricing occurred during a period of high renewable generation, with wind contributing 663.49 MW and solar contributing 330.05 MW to the regional supply mix.
The negative pricing was driven by an oversupply of renewable energy relative to local demand and export capacity constraints. A binding constraint (F_T+RREG_0050) with a marginal value of $4.22 was active during this period, indicating that transmission or regulatory limitations prevented efficient dispatch or export of excess generation, forcing generators to accept negative prices to maintain output. The high wind and solar output combined with restricted outflow capacity created conditions where curtailing generation was economically preferable to maintaining supply at constraining interconnection points.
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.