Commodity Demand — SA1: Monday 27 July 2026
South Australia's spot price sits at -$1.05/MWh at 06:30 AEST (28 July) with demand at 1,535 MW, deep in negative territory as wind generation of 1,608 MW comfortably exceeds current load. This continues a pattern that has held for most of the past 24 hours: demand has ranged from a low of roughly 971 MW overnight (05:15 AEST) to a peak above 2,150 MW mid-morning yesterday (09:15 AEST), and prices have tracked this closely, moving from small negatives at low demand to spikes exceeding $250/MWh briefly during the previous evening peak near 1,730-1,900 MW. Wind output above 1,600 MW is currently the dominant supply source, with gas (CCGT+OCGT combined under 44 MW) and battery output (12.9 MW) playing marginal roles — reflecting the strong wind resource driving prices below zero even as demand recovers from overnight lows.
The demand-price relationship today is asymmetric: at low demand overnight, prices fell as far as -$20/MWh (09:30 AEST previous day, 2,127 MW demand actually showed -$20, showing negative pricing isn't purely a low-demand phenomenon — it's wind-driven oversupply at any demand level). The sharpest price moves occur during ramp periods — evening ramp-up (17:00-21:00 AEST window) saw demand climb from ~1,400 MW to over 1,900 MW with prices swinging from negative to $250+/MWh within 30-45 minutes, illustrating SA's thin reserve margin once wind output tapers and gas must respond quickly.
AEMO's forecast trajectory for today shows prices staying suppressed through the morning (9-19/MWh range 21:00-03:00 AEST) before firming to $54-67/MWh through the 08:00-11:00 AEST window as demand rebuilds, matching typical morning ramp behaviour. Afternoon forecast prices ease back to $27-30/MWh (13:00-14:00 AEST) before climbing again to $54-56/MWh into the evening peak (16:00-18:00 AEST). Demand-side risk factors from market notices are relevant: AEMO issued and later cancelled LOR2 reserve conditions for SA on 29 July (not today), but the 27 July notices show recurring reserve tightness during 06:00-09:00 and 16:00-17