Carbon Forecast

Carbon intensity across the NEM is sharply bifurcated at 06:25 AEST. Tasmania sits at 0.00 tCO2/MWh on 100% renewables — entirely hydro and wind — while South Australia is the next lowest at 0.09 tCO2/MWh with renewables at 82.6%, driven by 547 MW of wind and backed by 116 MW of gas CCGT. At the other end, Victoria is the highest-intensity region at 1.01 tCO2/MWh with renewables at just 15.3% — 2,193 MW of brown coal dominates the mix alongside 133 MW of gas OCGT and a negligible 419 MW of wind. Queensland sits at 0.85 tCO2/MWh on 3.3% renewables, with 2,498 MW of black coal providing the near-totality of generation and solar output currently at zero. NSW reads 0.78 tCO2/MWh on 11.7% renewables, with 5,830 MW of black coal, 622 MW of hydro, and modest contributions from wind (115 MW) and solar (39 MW).

The intraday trajectory for NSW and Queensland tells a consistent story: both regions saw intensity fall during the morning solar ramp — NSW touched a trough of around 0.70 tCO2/MWh near 19:30–20:30 AEST as renewables peaked at ~20% — before solar output dropped and coal reasserted its share through the afternoon. Queensland showed a sharper reversal, with renewables collapsing from a brief ~23% overnight wind contribution back to under 4% by mid-morning as solar failed to materialise, leaving intensity locked above 0.84 tCO2/MWh for the bulk of the day. Victoria tracked similarly, with a midday dip to around 1.01 tCO2/MWh before intensity climbed back above 1.10 tCO2/MWh through the afternoon and is now easing slightly as evening wind picks up.

For carbon-sensitive scheduling, SA and Tasmania remain the clear low-intensity options throughout the day and into tonight. SA's intensity has been trending further downward through the afternoon — from 0.31 tCO2/MWh at 17:00 AEST to 0.09 tCO2/MWh now — as wind generation strengthens and gas backs off. That trajectory suggests SA will remain well below 0.10 tCO2/MWh through tonight. In NSW, the next viable green window will be tomorrow morning's solar ramp, typically commencing around 07:30–08:00 AEST, where intensity can drop toward 0.70 tCO2/MWh if solar conditions are favourable. Queensland offers no material green window during daylight hours given current rooftop and utility solar penetration levels — carbon-sensitive loads in that region are best deferred to overnight periods when wind occasionally lifts renewables above 20%. Victoria's brown coal baseload means intensity remains structurally elevated regardless of time of day, with the best relative windows occurring when wind output is elevated — watch for any increase above the current 419 MW as an indicator of marginal improvement.