Carbon Forecast: Wednesday 19 August 2026

NEM-wide carbon intensity spans a wide range this morning, from 0.060 tCO2/MWh in Tasmania to 0.835 tCO2/MWh in Victoria — a 14-fold difference that reflects each region's generation mix rather than demand alone. Tasmania sits at 90.8% renewable penetration on hydro (868 MW) and wind (359 MW), holding intensity below 0.10 tCO2/MWh for most of the past 24 hours. South Australia is the next-cleanest at 0.223 tCO2/MWh with 62% renewables, running on wind (505 MW) and battery output (241 MW), though gas (OCGT and CCGT combined around 457 MW) is covering the balance.

At the other end, Victoria's intensity has climbed to 0.835 tCO2/MWh with renewable penetration down to 30.5%, as brown coal generation (3,898 MW) dominates the mix alongside wind (1,367 MW). Victoria's trajectory data shows intensity has been rising steadily since midday, up from around 0.67 tCO2/MWh at 22:00 AEST yesterday to over 0.86 tCO2/MWh through the evening peak — a pattern consistent with wind easing off after the morning window. NSW (0.620 tCO2/MWh, 29.4% renewable) and Queensland (0.623 tCO2/MWh, 28.9% renewable) sit in a similar band, both leaning on black coal (5,554 MW in NSW, 5,285 MW in Queensland) with wind contributing over 1,100 MW in each region.

Looking at the trajectory pattern from the past 24 hours, all mainland regions show a consistent overnight low between roughly 01:00 and 05:00 AEST, when NSW intensity dropped as low as 0.415 tCO2/MWh (52.8% renewable) and Queensland fell to 0.402 tCO2/MWh (53.9% renewable) on stronger overnight wind output. Intensity then climbs through the morning as wind eases and demand builds, peaking in the early-to-mid afternoon window (roughly 13:00–15:00 AEST) across NSW, Victoria, and Queensland as coal and gas cover the bulk of load with minimal solar contribution in these outputs. For carbon-sensitive load-shifting today, the best windows remain the pre-dawn period (01:00–05:00 AEST) for NSW and Queensland, and continuously through Tasmania and South Australia given their consistently low intensity profiles. Victoria's window is narrower and shallower than the other regions, with even its overnight low only reaching the high-0.6 tCO2/MWh range.