Regional Outlook — SA1: Thursday 20 August 2026
South Australia's spot price sits at $101.02/MWh as at 06:30 AEST, tracking in line with overnight predispatch forecasts of $87-101/MWh through to 08:00. Demand has climbed to 1454 MW, up from the sub-400 MW trough recorded around 13:20-13:30 AEST overnight when the price briefly went negative (-$1.10/MWh) on the back of surplus wind generation. The past 24 hours have been volatile: prices spiked to $375/MWh at 09:10 AEST last night as demand peaked near 1653 MW, before collapsing to single digits in the early hours as wind output and low demand combined to push the market to near-zero and negative pricing.
The current generation mix draws on 360 MW of gas OCGT, 345 MW of wind, 243 MW of gas CCGT, and 141 MW of battery output, with solar at zero given the pre-dawn timing. Gas-fired generation (OCGT plus CCGT) totals 603 MW, roughly 55% of the 1090 MW mix shown in the snapshot, with wind contributing around 32%. Carbon intensity sits at 0.3244 tCO2/MWh with renewable penetration at 44.61%, both weaker than the overnight lows — intensity dropped as far as 0.0384 tCO2/MWh with renewable penetration above 92% around 02:30-05:30 AEST when wind was strong and demand light.
Predispatch forecasts point to prices holding in the $87-130/MWh band through the morning peak, before a sharp escalation flagged for the 09:30-11:00 AEST window today, with forecast RRP reaching $255/MWh at 09:30 and $188/MWh at 11:00. This aligns with the low wind and zero solar potential forecast for today (average wind potential of 1%, solar potential of 0%, 90% cloud cover), which will constrain renewable supply during the morning demand ramp. Prices are forecast to ease back to the $101-130/MWh range from midday through the evening, settling near $67.44/MWh by 18:00 AEST.
On notices, an inter-regional transfer limit variation remains active following a short-notice outage of the Tailem Bend to South East No.2 275 kV line at 14:15 AEST yesterday, invoking constraint sets S-BC_CP, S-SE_VC1_BC-2CP, S-SECB6611_10_BC-2CP and S-TBSE, which affect interconnector flows between SA, NSW, and VIC. Separately, AEMO's MT PASA update from 11 August flags Low Reserve Conditions for SA in July 2028 due to forecast unserved energy exceeding the reliability standard between August 2027 and August 2028 — a longer-term planning signal rather than an immediate operational concern. No active AEMO interventions are in place for SA today, though the 18 August direction to AGL's Torrens Island unit for voltage control support highlights the region's ongoing sensitivity to synchronous generator availability during periods of high renewable penetration.