commodity demand sa — SA1
South Australia's spot price sits at -$4.42/MWh with demand at 972 MW — a level roughly 400 MW below the overnight peak of ~1,390 MW seen around 10:30 AEST. The negative price is a direct consequence of solar generation ramping hard into low Sunday morning demand: rooftop and utility solar are overwhelming the grid's ability to absorb supply, with 91% cloud cover the only partial brake on what would otherwise be an even steeper price collapse. Wind is contributing 312 MW and gas CCGT holds just 80 MW as the marginal setter, keeping the floor in the -$4 to -$6/MWh range rather than the -$58/MWh extremes seen mid-morning yesterday when demand troughed below 30 MW at the solar peak.
The demand trajectory today follows a predictable Sunday profile. From the current 972 MW, demand will continue falling through the mid-morning solar peak — likely bottoming in the 300–600 MW range between 10:00–13:00 AEST based on yesterday's pattern, which pushed prices to -$49/MWh and below. The price floor during that window will be set by how aggressively rooftop solar penetrates: yesterday's 30 MW grid demand trough at 13:30 AEST produced prices as low as -$58.69/MWh, and today's conditions — slightly cooler at 20.9°C with high cloud at 91% — suggest solar won't be quite as dominant, which could keep the trough demand 100–200 MW higher and moderate the price floor accordingly.
The critical transition is the solar rolloff into the evening peak. Yesterday's data shows demand surging from under 500 MW at 15:20 AEST to over 1,500 MW by 19:00 AEST — a 1,000 MW ramp in under four hours — which drove spot prices from -$4/MWh to over $70/MWh. That same ramp is the watch point today. With carbon intensity currently at 0.0566 tCO2/MWh and renewables at 88%, the evening gas-backed peak will push intensity materially higher as CCGT and potentially OCGT units are called on to cover the solar void. Traders should flag the 16:30–19:30 AEST window as the primary price risk period, with yesterday's $55–$70/MWh band the likely reference range absent any demand or wind surprises.