Commodity Demand — SA1: Saturday 30 May 2026

South Australia's spot price sits at $10.62/MWh against demand of 1,324.92 MW at 06:30 AEST — well below the overnight trough of around 1,100 MW reached near 02:00 AEST but also well clear of today's daytime peak. The price-demand relationship through the past 12 hours has been sharply non-linear: demand above 1,800 MW during the 17:30–19:00 AEST window consistently produced prices in the $44–$58/MWh range, while demand below 1,200 MW during the 11:00–13:00 AEST overnight trough cleared at or below zero, including multiple intervals of negative pricing between -$2/MWh and -$0.09/MWh. This pattern reflects the supply stack structure in SA — when wind output is strong and demand is low, market-clearing prices compress sharply; as demand climbs into the 1,800–1,930 MW range, dispatchable capacity prices in and the stack steepens.

Wind is currently generating 1,187.76 MW, accounting for the overwhelming majority of supply against 1,324.92 MW of demand, with gas CCGT at 62.34 MW, OCGT at 0.11 MW, and battery at 1.71 MW. Renewable penetration is 95.01% with a carbon intensity of 0.0245 tCO2/MWh. This generation balance — strong wind near-dominating total demand — is the direct cause of the current sub-$11/MWh price. Any wind softening that forces additional CCGT or OCGT commitment would shift the marginal price rapidly upward given the current demand trajectory.

Today's demand outlook is the critical price variable. Forecasts for the 07:00–09:00 AEST window (21:00–23:00 UTC) converge around $10–$11/MWh, consistent with demand remaining in the 1,300–1,400 MW range through early morning. The morning ramp commences around 08:30–09:00 AEST and, based on the pattern from the prior day, demand is expected to climb toward 1,600–1,900 MW by 17:00–19:00 AEST. Forecast prices for the 08:00 AEST equivalent (22:00 UTC) cluster in the $40–$47/MWh range, and the 08:30 AEST window (22:30 UTC) centres around $35–$42/MWh — confirming the market expects meaningful price escalation through the morning ramp. Today's max temperature is forecast at only 15.2°C with average wind potential of 3.2 — materially lower than current conditions — suggesting wind may soften through the day, reducing the supply cushion that is currently holding prices down.

Demand-side risk for today centres on the morning peak ramp speed and wind resource availability through that period. With overnight wind strong and the generation fleet currently lightly committed on thermal plant, the transition from sub-$15/MWh conditions to the $40–$55/MWh range can occur within two to three dispatch intervals once demand clears approximately 1,600 MW and wind output begins to pull back. The near-zero overnight pricing window (00:30–05:30 AEST, UTC 14:30–19:30) also presents a clear load-shifting signal for