SA1 experienced sustained negative pricing between 04:40 and 05:05 on 3 September 2026, with prices reaching −$7.00/MWh over a 3-interval window. The region had high renewable generation (163–246 MW solar, 323 MW wind) concurrent with moderate gas-fired output (85 MW CCGT), creating conditions of structural oversupply during low-demand early morning periods.
The negative pricing reflects excess renewable generation that could not be economically curtailed or exported, forcing generators to pay to remain online. Multiple binding constraints with significant marginal values (F_TASCAP_LREG_0210 at $6.21/MWh, F_TASCAP_RREG_0220 at $4.98/MWh, and F_T+RREG_0050 at $4.46/MWh) indicate transmission limitations were active, restricting the region's ability to export surplus generation and likely preventing lower-cost dispatch solutions across the broader market. This combination of high renewable output, transmission constraints, and weak early-morning demand created the conditions for sustained negative settlement prices.
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.