SA1 experienced sustained negative pricing at -$1.02/MWh during the 12:30 settlement interval, with a secondary negative interval at -$0.49/MWh at 12:35, representing a minor pricing event. Prices declined sharply from $18.49/MWh at 12:05 to near-zero levels within 15 minutes before turning negative. The generation mix was dominated by wind output of approximately 1,861 MW, supplemented by battery discharge of 172.5 MW combined, with minimal gas and solar contributions.
The negative pricing was driven by binding constraint F_T+RREG_0050, which maintained consistent marginal values between $3.40 and $3.44 across all five settlement intervals, indicating a persistent network or dispatch constraint limiting generation offtake or requiring downward pressure on prices. High renewable generation (predominantly wind) combined with the binding constraint's restrictive effect created oversupply conditions in SA1, forcing the market into negative pricing to manage excess energy and maintain system security.
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.