Regional Outlook — SA1: Wednesday 16 September 2026

South Australia's spot price sits at $86.74/MWh as at 06:30 AEST, tracking within a wide band that has spanned negative pricing overnight to a peak above $110/MWh during this morning's demand ramp. Demand currently reads 1,484.83 MW. The past 24 hours illustrate SA's characteristic volatility: prices collapsed to as low as -$282.76/MWh between 03:00-05:00 AEST as wind generation surged against low overnight demand, before rebounding sharply through the 07:00-09:00 AEST period as demand climbed past 1,800 MW and prices firmed into the $95-111/MWh range. Prices have since eased back into the $65-100/MWh band through the day.

Generation mix at the current interval shows wind dominating at 1,118.65 MW, comfortably the largest source, with gas contributing a combined 288 MW (158.52 MW CCGT, 129.49 MW OCGT) and battery storage delivering 102.77 MW. Solar is at 0 MW, consistent with the 20:30 AEST timestamp after sunset. Renewable penetration sits at 80.92%, with carbon intensity at 0.1072 tCO2/MWh. This carbon intensity has fluctuated substantially over the past 24 hours, dropping as low as 0.0252 tCO2/MWh overnight when wind output was highest and renewable share topped 94%, then rising to 0.2908 tCO2/MWh around 04:25 AEST when wind eased and thermal generation picked up the load.

Predispatch forecasts point to a volatile session ahead. Prices are expected to fall further overnight, dipping into negative territory from around 23:00 AEST through to 06:00 AEST tomorrow (17 September), with troughs near -$8/MWh persisting for several hours — consistent with continued strong overnight wind generation against low demand. From 07:30 AEST tomorrow, forecast prices escalate quickly, reaching $132-170/MWh through the 08:00-12:00 AEST window as morning demand ramps against a lighter renewable contribution, before easing back to the $80-100/MWh range by late afternoon. Traders should note the wide forecast range (up to $170.44/MWh) reflects genuine tightening risk during that morning block.

Several active AEMO notices are relevant. A foreseeable market intervention for voltage support in SA has been flagged from 00:30 AEST today, continuing a pattern of near-daily voltage-related interventions and directions to AGL SA Generation (Torrens Island) seen through September. Separately, AEMO has issued a Minimum System Load (MSL1) advisory for 19 September, forecasting demand could fall to -178 MW between 11:30-14:30 AEST that day — a reminder of SA's ongoing minimum demand management challenge as rooftop solar and wind penetration grow. No transmission constraints specific to SA are currently active, though the VIC-SA negative settlement residue constraint was noted earlier this week.