Commodity Demand — SA1: Friday 4 September 2026
South Australia's spot price sits at -$4.84/MWh at 06:35 AEST with demand at 1,211 MW, extending a negative pricing stretch that's held for roughly the past three hours as wind generation of 1,341 MW comfortably exceeds underlying load. This is a region-wide pattern from overnight: demand troughed near 1,000-1,150 MW between 13:00-14:00 AEST yesterday, coincided with prices near zero to -$70/MWh, then climbed sharply through the evening peak to 1,792 MW around 11:45 AEST with prices spiking to $156/MWh intraday before wind resumed dominance and pushed prices back into negative territory by mid-afternoon. The pattern confirms SA's price sensitivity is now driven less by absolute demand and more by the demand-minus-wind residual — evening peaks above 1,700 MW only produced sustained high prices when wind output simultaneously dipped.
Today's forecast trajectory points to prices staying deeply negative overnight, with AEMO's curve showing -$16 to -$43/MWh through the 00:00-05:00 AEST window as minimum demand conditions persist, before a sharp reversal from 08:00 AEST (+$8/MWh) climbing to $20-35/MWh through the 09:00-17:30 window and a steep jump to $71.88/MWh forecast for 18:00 AEST as the evening ramp begins. This mirrors yesterday's pattern almost exactly: overnight troughs near zero-to-negative pricing, a midday rally, and an evening peak price spike as demand builds faster than wind can track it. Wind potential today averages 33.3% (moderate), with cloud cover at 48%, suggesting solar contribution will be limited and the evening demand ramp will again test the wind-versus-load balance.
Demand-side risk factors are elevated today. AEMO reclassified the Para-Templers West and Magill-Torrens Island A 275kV lines as a credible contingency from 00:00 AEST due to a severe weather warning, and an unplanned outage of the Keith-Kincraig 132kV line triggered interconnector constraints (S-KHKN) affecting SA's import/export capacity via Victoria. These network constraints, combined with a foreseeable AEMO intervention notice for SA voltage issues flagged yesterday, add operational risk to the evening peak — any wind underperformance during the 18:00-22:00 AEST ramp could produce price volatility beyond the forecast $72/MWh, similar to the $156/MWh spike seen at 22:10 AEST yesterday.
The five identified low-price windows for load-shifting all cluster in the 01:00-06:30 AEST band tomorrow morning, with the deepest opportunity at 04:30-05:30 AEST averaging -$36.23/MWh — a $108/MWh saving versus peak pricing. Flexible load and battery charging strategies should target this window, while any demand response or curtailment planning for the evening peak should account for the network contingency status given reduced transfer capability on the Keith-Kincraig corridor.