Commodity Demand — SA1 — Monday 4 May 2026

South Australia's spot price sits at $103.44/MWh with demand at 1,418 MW as of 6:35 AEST, having climbed steadily from around 1,326 MW at 5:30 AEST — a rise of roughly 92 MW in just over an hour that is tracking closely with this evening's price escalation. The demand-price relationship today is sharply defined: when demand sat in the 700–850 MW band overnight (approximately 1:30–4:30 AEST), prices were persistently negative, ranging from -$3 to -$11/MWh. The transition to positive territory was abrupt — prices crossed zero at 7:00 AEST (1,452 MW) and reached $105.08/MWh by 8:00 AEST as demand climbed through 1,780 MW. That ~330 MW demand increment from the pre-dawn trough to the morning peak triggered more than a $110/MWh price swing, indicating steep marginal cost stack compression in this demand range.

The current evening ramp is reproducing a similar but more sustained dynamic. Demand bottomed around 1,326 MW at 5:30 AEST before rising through the current 1,418 MW, while prices have pushed progressively from $60.08/MWh to $103.44/MWh across the same window. Generation is split across gas CCGT (184 MW), wind (88 MW), gas OCGT (81 MW), and zero solar output, with renewables comprising just 24.88% of the mix and carbon intensity at 0.4047 tCO2/MWh — the highest reading of the day. The combination of no solar, low wind output, and rising demand leaves gas plant setting the price. An active AEMO market notice confirms the No. 3 Leg of Directlink tripped at 02:30 AEST today, constraining SA's interconnector access to NSW and tightening the available import buffer precisely as evening demand rises.

Forecast prices for the 7:00–8:00 AEST half-hours are in the $113–$138/MWh range, implying the market expects another 50–150 MW of demand accretion to push the dispatch stack into higher-cost plant. Beyond 9:00 AEST, forecasts step up further — the 09:30 and 10:30 AEST windows carry multiple price estimates in the $175–$210/MWh range, consistent with morning peak demand approaching the 1,780–1,840 MW levels observed this morning. Grid stress sits at 74.5 (out of 100) and price stability scores 40.4, both reflecting the constrained interconnector position and tight peaking capacity margin. Flexible loads that can shift consumption to the 01:30–04:00 AEST window tonight are looking at prices in the $9–$50/MWh range — a $60–$100/MWh differential against the current price and a much wider gap relative to tomorrow morning's forecast peak.