Commodity Demand — SA1: Tuesday 1 September 2026
South Australia's spot price sits at $101.02/MWh with demand at 1,371 MW as at 6:25am AEST, holding in the middle of a day that has already swung from deeply negative territory overnight to a $220.67/MWh spike at 3:55pm yesterday. The overnight period saw demand collapse to as low as 764 MW around 12:35pm AEST (low-demand trough), driving prices to -$100/MWh and briefly -$119.67/MWh as minimum system load conditions took hold — wind and rooftop solar output outstripped underlying demand, forcing negative pricing to incentivise curtailment. As demand recovered through the morning ramp, climbing from 1,127 MW at 12pm to over 1,860 MW by 6:25pm AEST, price responded sharply, crossing from negative to $50/MWh by 5:55pm and peaking near $110/MWh through the evening ramp — a clear demonstration of SA's steep price-demand elasticity where each ~100 MW of load pickup can move price by tens of dollars.
The demand trajectory today shows the classic SA shape: an evening trough (currently near 1,300-1,400 MW), a morning ramp peaking around 1,860-1,890 MW near 6:25-6:55pm AEST, then easing through the day to a secondary low near 764 MW around 12:30pm before the evening peak rebuild. Forecast prices for the day ahead track this pattern closely — AEMO's own forecasts show a jump to $138.38/MWh around 8:30pm AEST tonight, easing to near-zero and negative territory ($0.01-$10/MWh) through the 1:30am-5am window, then climbing again to $101-$130/MWh through the 8am-10:30am peak before falling to near-zero by early afternoon and turning negative (-$4 to -$7/MWh) by late afternoon tomorrow as solar generation peaks.
Demand-side risk factors are notable today: AEMO has flagged a foreseeable intervention in SA from 10:30am AEST due to voltage conditions, continuing a pattern of recurring voltage-related directions to synchronous generators (AGL's Torrens Island and Barker Inlet units) seen repeatedly through late August. These interventions typically coincide with periods of low operational demand and high renewable penetration, when insufficient synchronous generation is online to maintain system strength — directly relevant given current renewable penetration sits at 64.9% with wind contributing 366 MW and battery storage 163 MW to the mix. Traders should watch the 12:30-2:30pm AEST window closely, where minimum system load conditions have hit repeatedly this week and price volatility (both negative price risk and voltage-driven intervention) is most likely to recur.