Commodity Demand — SA1: Tuesday 19 May 2026
South Australia is trading at $65.67/MWh with demand at 1,377 MW as of 06:30 AEST — a notably subdued level relative to the morning peak reached earlier in the session. The demand-price relationship across today's data is textbook: the morning ramp from around 860 MW at roughly 13:00 AEST to a session peak of 1,842 MW at 08:25 UTC (18:25 AEST) drove spot prices from the low $30s into the $76–$82/MWh range consistently. The correlation is tight — every sustained demand move above 1,700 MW has pushed prices above $70/MWh, while the overnight trough below 900 MW produced prices in single digits and multiple negative intervals, bottoming at -$45.73/MWh. The overnight period also saw brief spikes to $120/MWh at 09:10 and 09:25 UTC despite demand falling through 1,450 MW, pointing to constraint or rebidding activity rather than demand pressure at those moments.
Current demand at 1,377 MW sits in a transitional zone — the evening load is building from a post-6pm trough near 1,280 MW. The generation mix at this interval shows wind at 489.71 MW, gas OCGT at 148.25 MW, gas CCGT at 59 MW, and battery at 171.85 MW, with solar contributing nothing post-sunset. The 76.15% renewable share is keeping carbon intensity at 0.1442 tCO2/MWh, down from the 0.17+ tCO2/MWh levels seen during the higher-demand afternoon period when gas dispatch was heavier.
The forward forecast picture for the next few hours is instructive. Forecasts for the 07:00 UTC (17:00 AEST) half-hour target have been revised down steadily through the day — from over $107/MWh in early morning runs to $56.20/MWh in the 05:01 and 05:31 UTC runs — before rebounding to $78.74/MWh in the most recent 06:01 UTC run. This instability in the forecast RRP reflects genuine uncertainty about where demand lands as the evening progresses. Load window data points to softer pricing from 08:30 UTC (18:30 AEST) onward, with half-hour block forecasts in the $43–$50/MWh range, before stepping down sharply to the $20–$35/MWh band from 10:00 UTC (20:00 AEST) as overnight demand falls back below 1,000 MW.
Today's weather is a relevant demand driver: at 14.4°C with a heating demand index of 3.6 and 70% cloud cover, the pattern aligns with typical winter evening residential heating load lifting demand into the 1,400–1,500 MW range through the 07:00–09:00 AEST window. Tomorrow's forecast of clearer skies (21% cloud cover) and a similar temperature range of 10.9–16.9°C suggests a comparable demand profile, though improved solar availability during daylight hours may compress the afternoon price window relative to today. No SA-specific supply constraints or reserve notices are active in the current market notices.