Regional Outlook — SA1: Tuesday 8 September 2026
South Australia's spot price sits at -$3.61/MWh at 06:30 AEST, deep in negative territory as wind generation of 1,714 MW and rooftop/grid solar swamp overnight demand of 1,470 MW. This follows a volatile 24 hours: prices peaked at $159.06/MWh at 17:30 AEST yesterday during the evening ramp when demand hit 1,780 MW, before collapsing through negative pricing from 18:35 AEST onwards as wind output stayed strong into low-demand overnight hours. The current five-minute mix is wind-dominated at 1,714 MW, supported by 183 MW of battery discharge and 82 MW from gas CCGT, with solar at zero overnight and gas OCGT negligible at 0.11 MW.
Renewable penetration sits at 95.85%, with carbon intensity at just 0.0203 tCO2/MWh — near the lowest readings of the past 24 hours. This is a sharp improvement from the mid-morning trough yesterday, when intensity peaked near 0.30 tCO2/MWh around 07:00-08:00 AEST as gas plant ran harder to cover the demand ramp with renewable_pct dropping to around 49%. Today's overnight wind strength (10.7 MW average wind potential, 19 km/h wind speed) is keeping the region's carbon profile clean through the low-demand window.
Predispatch forecasts show prices staying negative or low through the morning: -$18.56/MWh by 10:00 AEST, bottoming near -$45.37/MWh around 15:00 AEST as wind and solar output build against soft midday demand, before a brief recovery to $70/MWh in the 18:00-21:00 AEST band as the evening ramp arrives. Prices then swing negative again into tonight's off-peak, per the forecast curve extending to 04:00 AEST tomorrow. Load-shifting windows show the best value between 13:00-14:00 AEST (-$40/MWh, saving $111/MWh versus peak) and 15:00-16:00 AEST (-$39/MWh).
Several active AEMO notices affect SA today: a voltage-related directive requires Torrens Island B4 (TORRB4) to remain synchronised and follow dispatch targets from 01:00 to 16:00 AEST, addressing forecast insufficient synchronous generation for voltage control. A related foreseeable intervention notice flags possible AEMO action from 11:00 AEST if market response is inadequate. Separately, unit ADPBA1 was declared non-conforming for a 6 MW deviation between 13:55-18:40 AEST yesterday. Traders and grid engineers should watch for further intervention updates given the pattern of directions on TORRB4 over the past several days, reflecting persistent voltage support needs as synchronous generation availability tightens during high-renewable periods.