Regional Outlook — SA1: Tuesday 15 September 2026

South Australia's spot price sits at $94.74/MWh as at 06:30 AEST, up sharply from the sub-$10/MWh and negative pricing that dominated overnight trade between 07:00-16:00 AEST yesterday. The region swung through a wide range over the past 24 hours — from -$16.15/MWh at 10:10 AEST yesterday during the overnight wind and low-demand trough, to a peak of $101.01/MWh at 06:20 AEST this morning as evening demand ramped through 1400-1475 MW. Demand currently sits at 1474.81 MW, consistent with the typical evening peak build.

Generation mix is wind-dominated, with wind contributing 1428.81 MW against total scheduled generation of roughly 1512 MW — around 94% of the supply stack. Gas fills the balance, with CCGT at 83.36 MW and OCGT negligible at 0.11 MW, while battery output is minimal at 0.09 MW and solar is at zero given the after-dark interval. Renewable penetration reads 94.48% and carbon intensity is 0.0271 tCO2/MWh, both consistent with the sustained low-carbon profile SA has held through the day — intensity has tracked between 0.024 and 0.032 tCO2/MWh since mid-morning as wind output remained strong.

Predispatch forecasts point to a firming trend into tomorrow's morning peak: prices ease to $23.94/MWh by 07:30 AEST tonight, fall further into negative territory overnight (-$6 to -$13/MWh between 23:30 and 05:30 AEST), then spike hard from 07:30 AEST tomorrow (16 September) — forecast at $71.06/MWh — rising steeply to $112.97/MWh by 08:00, $122.60/MWh by 09:00, and peaking at $136.10/MWh at 11:00 AEST. Prices stay elevated through midday before easing to the $90-100/MWh band by late afternoon. This trajectory reflects tomorrow's weaker wind potential (avg 2.1%) alongside rising solar potential (14.5%) as cloud cover clears to 28%.

Several active AEMO notices are relevant. A directed intervention remains in place for AGL's Torrens Island B4 unit, extended to 16:30 AEST today, to maintain voltage control given inadequate synchronous generation otherwise available in SA — a recurring theme this week with multiple TORRB4 directions issued since 11 September. AEMO has also flagged a Minimum System Load (MSL1) risk for SA on 19 September, with forecast demand dropping to -178 MW between 11:30 and 14:30 AEST that day, signalling a high renewable, low-demand event traders should watch for extreme negative pricing. No active constraints currently affect interconnector flows with VIC, though negative settlement residue constraints on the VIC-SA link were triggered multiple times over the past week during periods of high wind export.