Carbon Forecast: Sunday 23 August 2026

Carbon intensity across the NEM spans a wide range this morning: TAS1 sits at 0 tCO2/MWh with 100% renewable output (hydro 902 MW, wind 363 MW), and SA1 follows closely at 0.016 tCO2/MWh with 96.8% renewables, driven by 1,199 MW of wind against minimal gas (0.1 MW OCGT). At the other end, VIC1 is the highest at 0.787 tCO2/MWh with renewables at 35.5%, reflecting brown coal generation of 4,311 MW against 2,321 MW of wind. NSW1 (0.657 tCO2/MWh, 25.3% renewable) and QLD1 (0.621 tCO2/MWh, 29.0% renewable) sit in between, both anchored by large black coal fleets — 5,346 MW in NSW1 and 4,758 MW in QLD1 — with wind and battery output providing secondary contributions.

The generation mix explains the spread directly: TAS1 and SA1 carry negligible thermal generation and rely on hydro and wind respectively, while NSW1, VIC1, and QLD1 all depend on coal for the bulk of their load, keeping intensity elevated whenever wind and solar output is moderate. Over the past 24 hours, NSW1 and QLD1 both show a clear overnight trough — NSW1 fell to 0.333 tCO2/MWh around 01:00 AEST as wind generation lifted renewable share to 62%, before climbing back above 0.70 tCO2/MWh through the afternoon peak as demand rose and solar contribution stayed low. SA1 tracked an even deeper pattern, spending most of the afternoon and evening period below 0.02 tCO2/MWh with renewable penetration above 97%, reflecting sustained strong wind output.

For today's outlook, expect NSW1 and QLD1 intensity to remain in the 0.60-0.71 tCO2/MWh band through the middle of the day given the current mix, with the best green window opening overnight into the early hours of tomorrow (roughly 00:00-05:00 AEST) as wind typically strengthens and demand eases, potentially pushing NSW1 back toward 0.33-0.40 tCO2/MWh. VIC1 should track a similar but higher-intensity overnight improvement given its larger brown coal base, likely bottoming near 0.65-0.70 tCO2/MWh rather than approaching NSW1 lows. SA1 and TAS1 remain the standout low-carbon windows all day and are the preferred regions for any carbon-sensitive load shifting, with SA1 likely to stay under 0.05 tCO2/MWh for extended periods whenever wind holds above 1,000 MW, and TAS1 continuing at or near zero given its hydro-dominant baseload.