…. because it’s not as simple as some might initially think
[This article was initially written as part of this article here on the same day, but has been extracted separately so it can be separately referenced in future]
Those readers who want for the gory details can read them here, but the short story is that there’s essentially three measures of demand that are commonly talked about, and they are not really interchangeable. Starting from the top and working down…
| # | Measure of demand | Brief Explanation |
|---|---|---|
|
#0 |
‘Absolutely Everything Consumed’ |
This is something we don’t hear much spoken about because it would include other things, on the top of ‘Underlying demand’ in that we’d also add in energy consumed via Scheduled Loads (i.e. in charging batteries from the grid and the few pumped hydro as well). |
|
#1 |
‘Underlying Demand’ |
This measure is increasingly used, to represent ‘real’ consumption for purposes other than just time-shifting energy:
Given the invisibility of some aspects of this ‘behind the meter’ consumption, and also the ongoing opacity of rooftop PV (which is growing in volume) it seems most people estimate this by adding onto ‘Operational Demand’ the estimate of production from <100kW rooftop PV. |
|
#3 |
‘Operational Demand’ |
As we can see from the chart noted in this article on 1st Feb 2025, this measure the AEMO has only been publishing since late 2014 (and then only on a half-hourly basis). So only ~11 years of history in a market that’s >26 years old. Some might think about this as ‘Grid Demand’. AEMO increasingly refers to this because it most closely relates to the consumption that they can ‘see’ in real time, and hence relates to their ‘keeping the lights on’ functions. |
|
#3 |
‘Market Demand’ |
This measure the AEMO has been publishing on a 5-minute cadence (i.e. for every dispatch interval) since the start of the NEM. It’s a number that is fed into NEMDE and hence which plays a key role (along with bidding behaviour) in determining price outcomes. The MMS field name is ‘TOTALDEMAND’, but ironically it’s not ‘total’ in the layperson sense! Whilst AEMO increasingly looks at ‘Operational Demand’ many in the wholesale market still look closely at ‘Market Demand’ because that most closely relates to:
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