Commodity Demand — TAS1: Wednesday 2 September 2026
Tasmania demand sits at 1,105 MW as of 06:30 AEST, with spot price at $10.98/MWh after overnight volatility that saw prices swing from negative territory (-$4.69/MWh at 03:35 AEST) to a spike of $100.06/MWh at 11:10 AEST yesterday. The overnight low around 17:00-18:00 AEST saw demand trough near 892-895 MW with prices pinned near zero to $0.01/MWh, confirming Tasmania's near-100% renewable supply (wind 523 MW, hydro 153 MW) is easily covering base demand with minimal marginal cost. Price sensitivity to demand is pronounced above the 1,050 MW threshold — once demand pushed past 1,050 MW yesterday morning, prices jumped from the $25-60/MWh band into the $70-100/MWh range within a few dispatch intervals, indicating tighter dispatch conditions and reliance on higher-cost marginal generation as hydro/wind output is optimised against transfer constraints.
Today's forecast trajectory points to a sharp escalation from mid-morning. AEMO's forecast RRP holds near $0-19/MWh through to 06:00 AEST, consistent with current low-demand, high-renewable conditions, but then steps up materially: $109.94/MWh forecast for 07:00 AEST, climbing to $144-166/MWh through the 09:00-10:00 AEST window, and peaking at $183.57/MWh at 12:00 AEST. This mirrors yesterday's pattern where demand build from ~1,000 MW at 07:00 AEST to a peak above 1,240 MW around 08:20-08:25 AEST drove sustained $70-80/MWh pricing, with the true price peak lagging the demand peak by roughly 2-3 hours as afternoon dispatch conditions tighten further.
The critical driver today is the active constraint from the Tungatina 110 kV substation outage (unplanned, from 21:00 AEST yesterday), which has invoked the T-PMWA constraint set affecting the T-V-MNSP1 interconnector — this directly reduces Tasmania's import/export flexibility via Basslink and likely explains why price responses to demand increases are steeper than the underlying generation mix would suggest. With today's weather showing modest wind potential (12.2%) and better solar potential (8.1%) than recent days, and no heating/cooling demand pressure (max temp 11.5°C), the demand-side risk is manageable, but the binding transfer constraint means traders should expect price volatility to track the 07:00-13:00 AEST demand ramp closely, with the $150-180/MWh range plausible during the midday peak unless the substation outage is resolved.
Overnight low-demand windows remain attractive for flexible load: the 00:30-01:30 and 04:00-05:00 AEST periods are forecast at -$3.40/MWh and -$5.97/MWh respectively, offering roughly $187-190/MWh savings versus the midday peak for any shiftable industrial or storage charging load.