Commodity Demand — SA1: Saturday 8 August 2026
South Australia's spot price sits at -$6.25/MWh at 06:30 AEST with demand at 1,318 MW, the tail end of an overnight demand trough that bottomed near 1,179 MW around 03:20-03:30 AEST. Wind generation of 1,708 MW is comfortably exceeding total demand, pushing the region into negative pricing for most of the past six hours. The price-demand relationship tonight has been loose rather than tight: demand swung from 1,318 MW up to a peak of 1,893 MW (08:40 AEST yesterday evening) and back down without prices ever threatening positive territory beyond brief spikes to $46-54/MWh during the 06:40-06:55 AEST ramp, when wind output dipped briefly as demand climbed through the morning shoulder. This confirms SA's price formation today is being driven by wind availability rather than by demand levels alone — with 95.3% renewable penetration and carbon intensity at just 0.023 tCO2/MWh, thermal plant (84 MW of gas CCGT, negligible OCGT) is only setting price at the margin during short ramp windows.
Looking at the forecast trajectory, AEMO's price curve shows demand-driven firming through the day: forecast RRP holds negative to flat from 21:00-06:00 AEST, then climbs through the morning as demand builds, with a pronounced peak forecast around 12:00-12:30 AEST at $59.98/MWh and $50.59/MWh respectively — consistent with wind potential easing (BOM daily outlook shows just 8.1% average wind potential for 09 August, well down from recent days) while demand ramps toward typical midday/early-afternoon levels. A secondary elevated band appears 13:30-15:00 AEST ($36-46/MWh) before prices retreat to slightly negative by 17:00-18:00 AEST as the evening trough sets in. Traders should watch the 09:30-15:00 AEST window closely — that's where forecast demand and thinning wind supply intersect to produce today's only sustained positive pricing.
Two active AEMO market notices are directly relevant to today's supply-demand balance: a voltage-related foreseeable intervention flagged for SA from 05:00 AEST 09 August, and a live directions-based intervention event already running from 15:35 AEST 08 August. Combined with the credible contingency reclassification on the Brinkworth-Davenport/Templers West 275kV lines (issued 08 August due to severe weather), these indicate network security constraints layered on top of the demand cycle — a factor that could produce localised price volatility or direction-driven generation dispatch independent of the underlying demand curve. With wind potential forecast to average just 8.1% today under mostly cloudy skies (97% cloud cover, cooling/heating demand minimal at 5.1), any unexpected drop in wind output during the midday demand peak raises the risk of price outcomes exceeding the current forecast band.