Carbon Forecast: Saturday 12 September 2026

South Australia's carbon intensity sits at 0.038 tCO2/MWh this morning, the lowest in the NEM, with renewables covering 93.5% of demand — wind alone is contributing 1,665 MW against just 73 MW gas OCGT and 43 MW gas CCGT. Tasmania follows at 0.119 tCO2/MWh with 81.8% renewable penetration, underpinned by 344 MW hydro and 218 MW wind. At the other end, NSW carries the highest intensity at 0.746 tCO2/MWh with renewable share down at 15%, as 4,392 MW of black coal dominates the mix alongside modest wind (324 MW) and battery output (244 MW). Queensland sits at 0.648 tCO2/MWh (26% renewable) with 4,341 MW black coal and 1,381 MW wind, while Victoria reads 0.505 tCO2/MWh with renewables at 58.6%, driven by strong wind output of 3,014 MW offsetting 2,144 MW brown coal.

The overnight-to-morning pattern across the eastern regions shows intensity troughs typically forming in the early hours (00:00–04:00 AEST) as demand eases and wind generation holds up, then climbing sharply through the morning ramp as coal and gas cover the breakfast demand peak and solar has yet to build. NSW's trajectory over the past 24 hours illustrates this clearly: intensity fell to a low of 0.324 tCO2/MWh around 01:00 AEST with renewables near 63%, then rose steadily to peaks above 0.75 tCO2/MWh through the afternoon and evening as coal output firmed and renewable share fell below 15%. Victoria and Queensland show a similar but less pronounced overnight dip, bottoming near 0.53–0.60 tCO2/MWh in the late morning as wind ramps up, before climbing again into the evening peak.

For carbon-sensitive loads today, the clearest low-intensity window is South Australia continuously, given renewable penetration rarely drops below 90% through the day. Tasmania offers a secondary reliable window given hydro's consistent baseload contribution. In NSW, Victoria and Queensland, the most favourable period is likely to fall in the late morning to early afternoon (roughly 10:00–14:00 AEST) as rooftop and utility solar peak, mirroring the renewable percentage lift seen in yesterday's equivalent period across VIC and SA. Loads with flexibility should avoid the evening ramp (17:00–21:00 AEST), when solar drops away and thermal generation fills the gap, pushing intensity back towards the day's highs across all mainland regions except SA.