The Western Australian Wholesale Electricity Market (WEM) experienced a major price spike on 12 May 2026 (AWST), with prices surging from $155.64/MWh to $689.33/MWh across two consecutive five-minute trading intervals commencing at 07:05 AWST. The spike reached a peak of $689.33/MWh, representing a more than fourfold increase above the preceding price level. The event was relatively brief, spanning only two intervals (10 minutes), suggesting a transient supply-demand imbalance rather than a sustained system stress event.
The price spike occurred during early morning hours when solar generation was minimal (92.9 MW), placing greater reliance on thermal and wind plant to meet demand; the binding frequency control constraints (F_MAIN+RREG_0220 and F_T+RREG_0050) suggest that regulation raise ancillary service capacity was constrained, likely limiting the ability of the market to respond smoothly to a sudden supply shortfall or load change. With OCGT units (334.29 MW) appearing to have been dispatched heavily as peaking plant alongside coal and CCGT capacity, it is probable that a generator trip or unexpected reduction in output forced expensive fast-response plant to the margin, driving up the spot price. The binding regulation raise constraints further indicate that system inertia or frequency response obligations were tightening available generation headroom, amplifying the price outcome during this short but sharp event.
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.