Commodity Demand — SA1: Friday 11 September 2026
South Australia's spot price sits at $91.40/MWh at 06:30 AEST with demand at 1268 MW, tracking a steep overnight recovery after demand bottomed near 37-90 MW around 13:25-14:00 AEST yesterday, when prices fell as low as -$20/MWh. The overnight trough reflects minimal underlying load against 1027 MW of wind generation — SA is currently running at 96.16% renewable penetration with carbon intensity of just 0.0188 tCO2/MWh, wind alone covering roughly 81% of the 1268 MW demand.
Demand sensitivity is pronounced through the morning ramp: the 06:35-08:55 AEST window saw demand climb from 694 MW to over 1520 MW, dragging price from near-zero up to $110-112/MWh as load growth outpaced wind and solar contribution. Yesterday's evening peak (20:50-21:05 AEST) shows the clearest demand-price coupling in this dataset — demand peaked at 1490 MW and price spiked to $155.51/MWh, a rapid $70/MWh swing over just 15 minutes as the system tightened. That peak unwound quickly once demand eased below 1430 MW, with prices back under $95/MWh within 20 minutes.
Today's forecast trajectory points to a similar demand-driven pattern but with prices compressing more aggressively into negative territory. AEMO's curve shows prices firming to $94-98/MWh through the 07:30-11:30 AEST period as morning demand builds, before collapsing through midday — forecast at $44.28/MWh by 13:00 AEST and turning negative ($-1 to -$39/MWh) from 14:00 AEST through to at least 04:00 AEST tomorrow. This aligns with solar potential rising to 29.4% average today under a clearer sky (46% cloud cover) and a mild 12.2-21.2°C temperature band limiting both heating and cooling demand. Five low-price windows are flagged for load-shifting between 01:00-06:00 AEST tomorrow, with savings of $123-138/MWh versus peak pricing.
Demand-side risk sits with an active AEMO voltage intervention: a direction issued to AGL's Torrens Island B4 unit requires it to synchronise and follow dispatch targets from 09:00 AEST today through 16:30 AEST, addressing insufficient synchronous generation for voltage control as wind output dominates the mix. This is the fourth such SA voltage intervention in the past week, indicating tightening operability margins during high-renewable, low-demand periods even as spot prices remain contained.