Commodity Demand — SA1: Thursday 18 June 2026
South Australia's spot price sits at -$0.09/MWh with demand at 1,541 MW as of 06:30 AEST — a low-price, moderate-demand combination that reflects strong overnight wind generation of 1,726 MW against minimal gas dispatch (40 MW CCGT, effectively zero OCGT). The price-demand relationship across today's history is unambiguous: when demand peaked at 2,211 MW around 18:35–18:40 AEST this morning, prices held in the $10–$11/MWh range, sustained through the 18:00–20:10 AEST window. Conversely, the overnight trough — demand bottoming near 933–962 MW between 13:50–14:00 AEST — coincided with the deepest negative prices, including spikes to -$20/MWh across multiple intervals between 14:00–15:00 AEST. The demand-to-price transmission is tight and largely supply-driven: excess wind output at low demand depresses prices sharply, while the morning ramp from ~1,097 MW at 15:00 AEST to over 2,100 MW by 18:00 AEST pulled prices from -$20/MWh into positive territory within roughly 90 minutes.
The forecast trajectory points to a sharp repricing event beginning this evening. Prices are currently forecast to lift from $5.34/MWh at 07:00 AEST to $16.60/MWh by 08:30 AEST as the evening demand ramp takes hold, before escalating materially into the morning peak. By 09:30–10:00 AEST tomorrow (Friday), forecast prices reach $79–$81/MWh, sustaining above $60/MWh through to at least 14:00 AEST. This pattern — negative or near-zero prices during the wind-dominated afternoon, followed by high prices through the business-day peak — is the defining price shape for SA today. The weather context reinforces it: current wind potential of 21.1 (on a 0–100 index) is dropping sharply to 7.8 average for Friday and near-zero by the weekend, which means the afternoon low-price buffer that has suppressed spot prices through today's trading window will not persist into tomorrow's peak period.
Demand-side participants and flexible load operators should note that the overnight and early morning windows — particularly 01:30 AEST (-$1.00/MWh forecast) and 03:00 AEST (-$2.00/MWh) — represent the lowest-cost load windows before the prolonged high-price period that dominates Friday AEST business hours. The 06:30–14:00 AEST block is forecast continuously above $53/MWh, peaking at $81/MWh. There are no active SA-specific market notices affecting today's dispatch, though the active TAS LOR1 forecast for 25 June may influence interconnector flows on Heywood over the coming week and is worth monitoring for any spill-over into SA pricing.