Carbon Forecast: Tuesday 25 August 2026

Tasmania is running the cleanest grid in the NEM this morning at 0.053 tCO2/MWh with renewable penetration at 91.8%, underpinned by 1,182 MW of hydro output against just 125 MW of gas OCGT. South Australia sits second-lowest at 0.432 tCO2/MWh with 26.8% renewables, though this is well up from the sub-0.02 tCO2/MWh readings SA posted overnight when wind and solar covered close to 98% of demand — a reminder of how sharply SA's intensity can swing within a single day. Queensland carries the highest intensity at present, 0.779 tCO2/MWh with renewables at just 11.2%, reflecting 5,962 MW of black coal generation against only 234 MW of wind and negligible solar at this hour. NSW (0.707 tCO2/MWh, 19.1% renewable) and Victoria (0.841 tCO2/MWh, 30.0% renewable) sit in between, with Victoria's brown coal fleet contributing 4,258 MW alongside a strong 1,221 MW of wind.

The trajectory across NSW, VIC, QLD and SA over the past 24 hours shows a consistent pattern: intensity troughs in the early morning hours (03:00–06:00 AEST) as overnight wind generation peaks and demand is low, then climbs sharply through the morning as solar has yet to ramp and gas/coal cover the demand build. Intensity typically peaks in the late afternoon to early evening (16:00–19:00 AEST) as rooftop and utility solar fall away ahead of sunset while evening demand rises — QLD hit 0.857 tCO2/MWh and SA reached 0.496 tCO2/MWh at those points yesterday. Expect today's mainland regions to follow this same shape: intensity easing through the morning solar ramp, a modest midday dip in NSW, VIC and SA as rooftop and utility PV peaks, then a steady climb into this evening's demand peak.

For carbon-sensitive loads, the best windows today are pre-dawn (00:00–05:00 AEST) across all mainland regions when wind generation is typically strongest relative to demand, and a secondary midday window (11:00–14:00 AEST) in VIC and SA where solar penetration lifts renewable share meaningfully — VIC touched 36% renewables and SA topped 68% around midday in the prior session. QLD's solar contribution remains structurally smaller, so its lowest-intensity window is likely to stay confined to the early hours before sunrise rather than midday. Tasmania requires no timing strategy — its hydro-dominated mix keeps intensity low and stable across the full 24 hours, making it the standout region for any load shifting or carbon-optimised scheduling today.