As time permits, will flesh out an explanation of how the Scheduled category currently operates in the NEM, and how it has evolved.
(A) Summary of current arrangements
If a unit is registered with the AEMO … be it a Generator, or a Load (or a Bi-Directional Unit or Integrated Resource Provider following the IESS change) … that unit (i.e. DUID) can be registered as:
- fully Scheduled; or
- Non-Scheduled; or
- from 31st March 2009, Semi-Scheduled for VRE units (Wind and Large Solar).
(B) Chronology of evolution
In the following table, we’ve highlighted some of the key dates with respect to the evolution of registration in the NEM, as it pertains to the Scheduled category.
| Date | Description |
| 13th December 1998 (Start of the NEM) |
At the start of the NEM generators supplying the NEM were registered as Scheduled or Non-Scheduled. The Semi-Scheduled registration category did not exist. |
| Early 1999 | The aluminium smelters in Victoria were registered as Scheduled Loads for a brief time at the start of the market – however that registration status was allowed to lapse. |
| 31st March 2009 | At this point, the Semi-Scheduled category came into existence. At this point a number of larger Wind Farms, which were registered as Scheduled to that point, transferred to the Semi-Scheduled registration category. |
| When in 2017? | Registration threshold set at 5MW (i.e. down from the 30MW criteria that applies to slower-responding generators) was implemented for batteries in conjunction with the development of the Hornsdale Power Reserve. |
More context might be added later…
(C) Other useful references
On this WattClarity(r) site, any articles tagged with ‘Scheduled’ can be found here.
Will add in other links to useful references as time permits…