A major binding constraint (N_QPSFB_L_9INV) with an exceptionally high shadow price of $812,000/MWh was active in NSW1 on 18 July 2026 during the 08:15–08:40 settlement period, whilst the regional reference price remained stable around $90.49/MWh. The constraint significantly exceeded the marginal value of other active constraints by several orders of magnitude, indicating severe congestion or operational limitation in the constrained element.
The unusually high shadow price suggests the constraint was actively restricting dispatch and limiting available capacity to serve demand or maintain system security. The generation mix at the time comprised predominantly dispatchable sources (black coal 6,851 MW, battery 1,092 MW, hydro 1,628 MW) alongside substantial wind generation (640 MW), but the binding constraint's extreme marginal value indicates that physical or operational limitations—rather than fuel scarcity or generation availability—were the limiting factor preventing lower-cost or preferred dispatch outcomes.
Causal analysis generated by gridIQ's synthesis model from live AEMO market data: dispatch prices, generation mix, interconnector flows and market notices in the interval surrounding the event.