Commodity Demand — SA1: Friday 19 June 2026

South Australia is currently sitting at 1,428.5 MW with a spot price of $71.54/MWh at 06:30 AEST, a relatively subdued demand level consistent with the early Saturday morning trough following overnight lows in the 1,350–1,480 MW range. The price-demand relationship across the past 24 hours has been pronounced: demand peaked near 2,123 MW between 08:20–08:35 AEST yesterday, coinciding with spot prices in the $75–$92/MWh band, while the overnight valley below 1,400 MW saw prices compress into the $50–$60/MWh range. The most notable sensitivity point was the 13:00 AEST period where demand remained above 1,600 MW and prices held in the $60–$80/MWh corridor, confirming the market's marginal cost stack tightens quickly above roughly 1,800 MW in this winter configuration.

The forward price curve is signalling a sharp escalation through tonight's evening peak. Forecasts show prices lifting from $70/MWh at 07:00 AEST to $89–$104/MWh by 08:30–09:00 AEST, with the 08:30–10:00 AEST window sustaining prices above $100/MWh. The Saturday morning demand build — driven by heating load at a current temperature of 10.4°C and a forecast maximum of only 13.6°C — is expected to push demand back toward the 1,900–2,100 MW range, replicating the conditions that produced $75–$92/MWh prices during yesterday's equivalent period. Today's wind resource is materially weaker (wind potential 2.9 now, forecast average 1.1 for the day) compared to overnight when wind was supporting a 64.3% renewable share, which tightens the supply stack further and explains the premium priced into the morning peak.

The current generation mix — 530 MW wind, 191 MW gas OCGT, 120 MW gas CCGT, 30 MW battery, zero solar — is covering 1,428 MW at $71.54/MWh without notable stress. As solar remains absent and wind moderates through the morning, gas plant will need to increase output to meet the demand ramp, shifting the marginal price upward. The optimal low-cost windows for flexible or deferrable load are concentrated between 01:30–06:00 AEST ($51–$58/MWh), with the best single hour from 03:30–04:30 AEST averaging $51/MWh — some $62/MWh below the forecast midday peak. Traders and demand-response managers should note the forecast holds prices above $85/MWh continuously from 08:00 AEST through to at least 20:00 AEST, with a peak of $113.86/MWh forecast at 22:30 AEST, pointing to sustained afternoon and evening tightness driven by low solar availability and diminished wind throughout the day.