Commodity Demand — SA1: Wednesday 9 September 2026
South Australia's spot price sits at $96.60/MWh as at 06:30 AEST, with demand at 1,527 MW and climbing on the back of the overnight evening peak. This follows an extraordinarily volatile 24 hours: demand troughed near 490 MW around 14:30-15:00 AEST (04:30-05:00 UTC) overnight, dragging prices as low as -$101/MWh, before the morning ramp pushed demand to a daily high of 1,994 MW at 20:25 UTC (approximately 05:55 AEST), coinciding with prices peaking at $99.68/MWh. The pattern is a textbook demand-price correlation for SA: every 500 MW swing in demand across the trough-to-peak cycle corresponds to a price swing exceeding $150/MWh, reflecting the region's thin reserve margin and heavy reliance on wind and gas peaking plant to firm the ramp.
Wind is currently supplying 1,606 MW against total generation of roughly 1,663 MW, putting renewable penetration at 97.4% and carbon intensity at just 0.0128 tCO2/MWh — near the lowest readings of the past 24 hours. Gas CCGT is contributing a modest 43 MW and battery output sits at 13 MW, indicating minimal thermal backup is required while wind remains strong. This high wind output is central to price formation: the negative pricing intervals overnight (several intervals below -$15/MWh, with troughs near -$101/MWh) occurred when wind generation outstripped low overnight demand, forcing exports or curtailment.
AEMO's forecast trajectory points to a further price spike this evening, with the 21:00-21:30 AEST window forecast at $80-113/MWh before falling sharply through the evening off-peak and turning negative again by 23:00 AEST, bottoming near -$90/MWh around 04:30 AEST tomorrow. A separate forecast note flags a foreseeable voltage-related intervention in SA from 10:00 AEST today, with AEMO warning it may need to issue a direction absent sufficient market response by 17:00 yesterday — a signal that synchronous generation constraints, not just demand, could add price volatility risk during today's peak.
Demand-side data confirms today's outlook: cool overnight temperatures (7.2°C, minimal cooling demand) kept underlying load subdued in the small hours, while forecast solar potential of 34% for today should support a moderate midday demand offset. Traders should expect the current $80-100/MWh band to hold into the early evening peak before another steep decline into negative territory overnight, consistent with SA's typical high-wind, thin-margin pricing pattern.