Regional Outlook — SA1: Sunday 23 August 2026
South Australia's spot price sits at $49.43/MWh at 06:30 AEST, down from a volatile overnight and morning session that saw prices swing from $118/MWh during Saturday evening peak demand down to negative territory (-$7.86/MWh) through the low-demand overnight trough, before spiking again to $100/MWh at this morning's 08:25 demand ramp. Demand currently sits at 1,370 MW, easing from the 1,605 MW peak recorded mid-morning. The 24-hour pattern shows the now-familiar SA signature: negative or near-zero prices overnight on wind oversupply, a sharp morning ramp as solar hasn't yet built and demand rises, then moderation through the day.
Generation mix is heavily wind-dominated this interval: wind is contributing 1,358 MW against total generation of roughly 1,411 MW, with gas CCGT at 42.7 MW, battery discharge at 10.6 MW, gas OCGT negligible at 0.11 MW, and solar at zero (overnight/pre-dawn interval, reinforced by 100% cloud cover today). Renewable penetration sits at 96.97%, consistent with SA's pattern of near-total renewable supply during high-wind overnight and early-morning periods. Carbon intensity is correspondingly very low at 0.0149 tCO2/MWh, though the carbon history shows this fluctuates significantly through the day — climbing to 0.32 tCO2/MWh at 07:30 AEST as gas generation stepped in to cover the morning demand ramp when wind output eased, before falling back toward 0.014-0.015 tCO2/MWh through the afternoon.
Predispatch forecasts point to a further price decline through the evening: $44/MWh at 21:00, easing to $13/MWh by 22:30 and turning negative overnight with a trough near $0/MWh around 03:00-04:00 AEST tomorrow, consistent with continued strong wind output and low demand. Tomorrow's morning ramp is forecast to be sharp — prices lift to $67.50/MWh by 06:30, $92/MWh by 07:30, and peak near $109.96/MWh around 09:30 AEST as demand builds ahead of any solar contribution, with today's forecast showing zero solar potential given full cloud cover. Wind potential firms modestly to 5.9% tomorrow but weather outlook shows limited solar recovery until midweek.
Active market notices show a cluster of AEMO interventions in SA over the past several days tied to voltage control: directions were issued to AGL SA Generation's Torrens Island (TORRB2, TORRB3) and Barker Inlet units to synchronise and follow dispatch targets, with AEMO citing insufficient synchronous generation to maintain secure voltage control during periods of high renewable output. The Barker Inlet direction was cancelled as of 11:00 AEST 23 August, and the Torrens Island direction was expected to run until 13:30 that day. These interventions are consistent with SA's recurring need for synchronous plant to support grid strength during high wind/low synchronous generation periods — traders should watch for further voltage-related directions given today's continued high wind share and thin gas generation.