Carbon Forecast: Thursday 13 August 2026

Tasmania holds the NEM's lowest carbon intensity this morning at 0.051 tCO2/MWh, underpinned by 92.2% renewable penetration as hydro (970 MW) and wind (487 MW) supply nearly all of the region's load. South Australia sits second-lowest at 0.410 tCO2/MWh with renewables at 29.3%, though its mix currently leans on gas OCGT (444 MW) and CCGT (346 MW) alongside 110 MW of wind and a fully drawn-down battery. At the other end, Victoria carries the highest intensity at 0.866 tCO2/MWh, with brown coal (4,362 MW) dominating the mix and renewables at 28.2%. NSW (0.681 tCO2/MWh, 22.5% renewables) and Queensland (0.704 tCO2/MWh, 19.6% renewables) both sit in the mid-high 0.6-0.7 range, with black coal supplying the bulk of load in each — 6,832 MW in NSW and 5,678 MW in QLD.

Overnight-to-morning data shows a clear diurnal pattern repeating today. NSW and QLD both hit their lowest intensity overnight between 0300-0500 AEST, troughing near 0.456-0.507 tCO2/MWh as wind generation firmed and demand eased, before climbing sharply through the morning ramp as coal plant ramps to meet rising load. NSW intensity peaked near 0.786 tCO2/MWh around 1900-2000 AEST as solar dropped away and evening demand built. SA showed the widest swings, troughing at 0.154 tCO2/MWh around 0500 AEST on strong wind output, then spiking above 0.53 tCO2/MWh through midday as wind eased and gas plant filled the gap.

For carbon-sensitive loads today, the best windows are pre-dawn through mid-morning, roughly 0200-0600 AEST, when wind generation is typically strongest across NSW, SA and QLD and coal ramping hasn't yet picked up for the day's demand curve. Tasmania offers a consistently low-carbon window all day given its hydro-wind base, making it the most reliable region for continuous low-intensity operation. Expect NSW, QLD and VIC to track back toward their evening peaks (0.75-0.92 tCO2/MWh) as today's afternoon transitions into the 1800-2000 AEST demand peak, when solar output falls away and thermal plant carries more of the load. SA remains the most volatile region to watch — its intensity can swing by a factor of three within hours depending on wind output, so traders targeting green windows there should track intraday wind forecasts closely rather than relying on time-of-day alone.