Commodity Demand — SA1: Monday 20 July 2026
South Australia's spot price sits at $117.06/MWh at 06:25 AEST with demand at 1,554 MW, up from an overnight low near 1,165 MW around 04:35-04:40 and well below yesterday evening's peak of 2,129 MW at 09:05. The region is tracking through the morning ramp, with demand climbing roughly 390 MW over the past hour as the working day begins — this mirrors the pattern from the prior 24 hours, where demand above 1,900 MW consistently pushed prices into the $120-$138/MWh band, while troughs below 1,300 MW saw prices fall to $40-60/MWh. This demand-price relationship is tight in SA: every 100 MW step above roughly 1,700 MW has been adding $10-20/MWh to RRP as gas-fired plant (GAS_OCGT and GAS_CCGT currently supplying 331.79 MW and 323.53 MW respectively, over 42% of the mix) sets the marginal price with wind at 408.56 MW and solar at zero given overcast, low-solar-potential conditions (88% cloud cover, 0 solar potential currently).
AEMO's forecast trajectory points to a firming afternoon and evening peak: forecast RRP climbs to $138.04/MWh by 22:00 AEST and spikes to $178.38/MWh around 22:30 AEST, consistent with the evening demand ramp typically seen in SA between 17:00-20:00 as solar drops away and heating load builds — daytime heating demand is already at 7.7 (index) with temperatures at 10.3°C and forecast max of just 15.5°C today, reinforcing sustained thermal demand. Through the middle of the day (12:30-18:00 AEST), forecast prices ease into the $30-90/MWh range as solar (limited today) and wind contribute more, before firming again into the evening peak — traders should note the identified low-price window from 17:30-18:30 AEST tomorrow (21 July) at an average $21.80/MWh, reflecting the trough between morning and evening demand peaks.
No demand-side constraints or reserve notices are currently active for SA1; the relevant market notices concern a completed Tailem Bend 275kV capacitor bank outage (constraint set S-TBCP1 affecting SA-VIC interconnector transfer) and a VIC-SA negative settlement residue constraint from mid-July, both non-active for