Commodity Demand — SA1: Wednesday 16 September 2026
South Australia's spot price sits at $86.74/MWh at 06:30 AEST with demand at 1,485 MW, down from the overnight evening peak of 1,880 MW recorded around 09:25 AEST yesterday evening (local settlement time markers), when prices held near $101-112/MWh. The current price reflects a market still working through the morning demand ramp, with wind contributing 1,119 MW of the 1,509 MW generation mix — comfortably meeting current load and keeping the region at 80.9% renewable penetration and 0.107 tCO2/MWh carbon intensity.
The price-demand relationship over the past 24 hours is stark. Overnight minimum demand collapsed to below 200 MW between 03:00-05:00 AEST, driving prices deeply negative — troughing at -$282.76/MWh at 03:45 AEST — as wind generation outpaced minimal load. As demand recovered through the 06:00-09:00 AEST ramp, climbing from 640 MW to over 1,800 MW, prices swung sharply positive, peaking near $112/MWh at 08:15 AEST. This demand-price elasticity is typical for SA's wind-heavy, low-inertia grid: every 100 MW shift in demand is currently translating to $10-20/MWh price movement given thin operating margins.
AEMO's forecast trajectory for today points to a stronger afternoon price signal than current levels suggest. Forecast RRP climbs to $132-170/MWh across the 08:00-12:00 AEST window, with a peak forecast of $170.44/MWh at both 09:00 and 11:30 AEST, before easing to $82-125/MWh through the afternoon and evening. This aligns with forecast low wind potential (0.6% average) and moderate solar (35.3%) for today, meaning the grid will lean more heavily on gas (currently CCGT 159 MW, OCGT 129 MW) and battery dispatch (103 MW) to cover the midday-afternoon demand block, supporting firmer pricing than the current sub-$90/MWh level.
Demand-side risk factors are notable: AEMO has flagged a foreseeable intervention for voltage support in SA from 00:30 AEST today, continuing a pattern of near-daily voltage directions to synchronous plant (including repeated Torrens Island directions) to maintain system strength amid high renewable output. Separately, AEMO's minimum system load notice for 19 September flags forecast demand as low as -178 MW around 13:30 AEST that day — not today's session, but a signal that shoulder-season minimum demand risk remains acute across the working week and will keep pressure on negative pricing during low-demand, high-wind troughs.