Carbon Forecast: Tuesday 21 April 2026

Tasmania is running at 0.00 tCO2/MWh with 100% renewable generation — hydro (360 MW) and wind (133 MW) covering the entire state load with no thermal on the system. South Australia is next at 0.18 tCO2/MWh with 64% renewables, wind supplying 386 MW alongside a 216 MW gas CCGT baseload unit. Both regions represent the lowest-intensity consumption windows on the NEM right now and have sustained those positions across the full dataset period.

Victoria sits at 0.72 tCO2/MWh with 39% renewable penetration, driven by 1,084 MW of wind alongside 1,562 MW of brown coal and 110 MW of gas OCGT. Intensity in VIC1 tracked above 1.00 tCO2/MWh during the 07:00–08:30 AEST morning peak before wind generation progressively pushed it down through the afternoon to its current level. NSW1 and QLD1 are the highest-intensity regions on the NEM, both sitting at approximately 0.86 tCO2/MWh with renewable penetration below 3%. NSW1 is almost entirely black coal (5,391 MW) with 93 MW wind and 65 MW solar, while QLD1 runs 2,566 MW of black coal with hydro at 64 MW and negligible other renewables.

The data shows NSW1 had its lowest-intensity window of the day around 09:00–09:30 AEST (0.78 tCO2/MWh, ~11% renewables) as solar contributed to the morning mix before dropping back. That modest solar uplift is now gone as the dataset extends past 06:30 UTC (06:30 AEST is 16:30 AEST — noting the interval timestamps are UTC, so the 20:30 UTC entry corresponds to 06:30 AEST the following morning). Correcting for UTC+10: the latest data point at 20:30 UTC is 06:30 AEST on 22 April. The morning solar ramp for NSW1 and QLD1 is therefore imminent — based on the prior day's trajectory, expect NSW1 intensity to dip toward 0.78–0.79 tCO2/MWh between approximately 09:00–10:00 AEST as solar generation ramps. QLD1 showed minimal solar response in the prior period, with renewables staying below 3% through the day, so no meaningful intensity relief is expected there.

For carbon-sensitive loads, SA1 and TAS1 remain the optimal dispatch windows throughout the day. SA1 sustained sub-0.10 tCO2/MWh intensity from roughly 10:30–17:30 AEST in the prior day's profile, with the midday solar peak pushing renewables above 89%. A similar window is likely today between approximately 10:00–16:00 AEST. VIC1's best window was the 14:00–19:30 AEST period at 0.55–0.58 tCO2/MWh; that range is likely to recur today as wind holds. Flexible loads in NSW1 and QLD1 should target the 09:00–10:30 AEST solar window if deferral is possible, as that represents the only period of measurably reduced intensity