We have been asked this question by a number of people (with references to several articles we have published on WattClarity®), as there are a number of different ways of reporting “demand”.
Depending on the source of the data (i.e. which software package we used), it could be any of the following:
NEM-Watch (for a real-time view)
NEM-Watch provides a real-time view of the National Electricity Market.
As such, it updates two different data sets from AEMO/NEMMCO:
1) Dispatch Data is the 5-minute data AEMO uses to dispatch the market.
(a) This data is produced in the NEMDE dispatch engine at the beginning of each (5-min) dispatch interval and applies as the end of the dispatch interval.
(b) The measure of demand is called the Dispatch Demand Target.
(c) Hence it is a forecast (at the beginning of the dispatch interval) what the demand will be at the end (hence the name “Target”).
(d) NEMMCO/AEMO calls it “TOTALDEMAND”. Because of the small time-scale involved, it tends to be reasonably accurate, but is not the same as a metered demand.
2) Trading Data is the 30-minute data AEMO uses for commercial transactions in the market.
(a) The Trading Demand Target is just the simple (i.e. time-weighted) average of 6 x 5-minute Dispatch Demand Target numbers in the trading interval.
(b) Hence, this figure (too) is not a metered demand
NEM-Review (for historical analysis)
As trading (30-min) data is what is used for all commercial transactions in the market, the NEM-Review package provides updates of just this data set.
Hence, the demand numbers shown in NEM-Review at Trading Demand Target.
NEMforecast (for forward-looking data)
Data published in the PASA process by AEMO is for a given half-hour (or, in the case of MT PASA, for the highest demand half-hour in the day), hence it is the equivalent of Trading Demand Target.