Aggregate Scheduled Target (AggSchedTarget)

On this page we explain the metric ‘Aggregate Scheduled Target’, which we sometimes abbreviate as ‘AggSchedTarget’.

(A) About the metric

This metric is a useful proxy for the requirement for Firming Capacity (in every Dispatch Interval), in that it can be trended since the start of the NEM in order to ascertain what’s changing, and what remains the same:

1) is calculated individually for all ~110,000 dispatch intervals each year

2) represents the simple sum of dispatch Targets for all ‘firming’ capacity in the NEM:

(a) Hence it:

i. looks at supply-side units (i.e. injections into the grid);

ii. counts all Scheduled units

iii. covers a range of different technology options – including:
1. older thermal technology (coal, gas and liquid-fired), plus
2. hydro
3. plus also batteries and negawatts.

(b) The one criteria is that the units must be fully dispatchable … so this does not take account of Targets for Semi-Scheduled units (which don’t have to follow targets) and Non-Scheduled units (which don’t even get given targets).

(c) Being fully dispatchable is just one component of the ‘keeping the lights on services’ we first wrote about in the GRC2018.

This metric is useful in absolute terms, but also in understanding such aspects as:

1) aggregate ramp rates required (across the day, or from one dispatch interval to the next); and also

2) The predictability of the requirement … which we can assess using a ‘Forecast Convergence’ approach.

(B) Use of this metric

This metric has been used in a variety of locations, including:

(B1) In the WattClarity Deeper Insights reports

This metric was first introduced in Appendix 15 within GenInsights21 … with analysis then continued into GenInsights Quarterly Updates (in Appendix 4 therein).

(B2) Articles on WattClarity

Here on WattClarity, you will find articles utilising this metric:

1) Collated under the ‘Requirement for Firming Capacity’. category; and or

2) Tagged with any of the following:

(a) AggSchedTarget; and/or

(b) ‘Aggregate Scheduled Target‘; or occasionally

These articles include a growing number of Case Studies