From the start of the NEM through until 2001, the NEM was typified by a pricing dichotomy with sustained rock-bottom pricing in NSW, Snowy and Victoria and high and volatile pricing in the extremities (Queensland and South Australia).
In 2001, the QNI interconnection and many generation projects were developed. This led to the convergence of prices between all regions, and the disappearance of price volatility – circumstances that were a real threat to generator profitability.
In response, generators adopted an approach that came to be known as “the economic withholding of capacity” to engineer volatility into the market throughout winter 2002 – and hence higher prices as a result., and generator behaviour.
A number of factors were probably contributing. Murraylink has been offline for several days and Heywood was severely constrained at the time of your snapshot. Pelican Point has had only one GT running for about a week but was completely offline since 0130. Solar was depressed late morning because of a weather front which has led to transmission line warning market notices for SA. Many of the gas peakers were called on during the day.