Commodity Demand — SA1: Tuesday 15 September 2026
South Australia demand sits at 1,475 MW as of 06:30 AEST, with the spot price at $94.74/MWh — up sharply from sub-$60 levels three hours earlier as the region moves through the evening peak. The overnight-to-morning trajectory illustrates SA's extreme price sensitivity to demand swings: demand troughed near 400-500 MW between 02:00 and 05:00 AEST, coinciding with prices pinned in negative territory (-$5 to -$9/MWh) on the back of wind generation exceeding underlying load. As demand climbed through the 07:00-09:00 AEST ramp, rising from roughly 1,050 MW to over 1,800 MW, prices snapped from negative/near-zero to the $50-70/MWh band within a single hour — a swing of over $70/MWh for a ~750 MW demand increase, underscoring how thin the region's flexible supply margin is once wind output plateaus.
Today's demand peaked near 1,880 MW around 09:15-09:30 AEST before easing back through the middle of the day to the 1,400-1,500 MW range by mid-afternoon, then climbing again into this evening's peak. Prices tracked this pattern closely: the 08:00-11:00 AEST window held in the $55-75/MWh band as demand approached its daily high, eased to $30-60/MWh through the 1,400-1,500 MW midday trough, and are now pushing back above $90/MWh as demand rebuilds toward tonight's evening peak. AEMO's forward price curve points to a further step-up tomorrow morning, with forecast prices climbing from single digits at 07:00 AEST to $113-137/MWh through the 08:30-11:00 AEST window — a stronger morning peak than today's, consistent with tighter forecast conditions.
Wind is currently supplying 1,429 MW against total demand of 1,475 MW, with gas (CCGT) contributing 83 MW and battery/OCGT negligible — renewable penetration sits at 94.5% and carbon intensity at 0.027 tCO2/MWh, both near the best levels seen over the past 24 hours. This heavy wind reliance is the direct driver of today's price volatility: when wind output is abundant relative to demand (overnight trough), prices collapse to negative; when demand rises faster than wind can track, or wind eases, prices spike into the $90-100+/MWh range as gas and imports are called on at the margin.
Several active AEMO notices are relevant to today's demand-side risk profile. A directed synchronous generator (Torrens Island B4) remains online under voltage-control direction until 16:30 AEST today, reflecting an ongoing shortage of synchronous plant to manage system strength as wind dominates the mix — this constrains dispatch flexibility rather than demand itself. Separately, AEMO has flagged a forecast Minimum System Load (MSL1) event for 19 September, with operational demand expected to fall as low as -178 MW between 11:30 and 14:30 AEST that day, signalling minimal underlying demand net of rooftop solar is likely later this week. For today, no minimum load risk is flagged, and the demand trajectory — peak near 1,880 MW this morning, a second evening peak now building past 1,475 MW — remains the key driver of the $0-135/MWh price range traders should expect across the day.