Measuring Solar PV

We’ll expand this page in future when we have more time.

For now, we just wanted to be able to highlight that there are essentially three different size categories generally discussed in relation to solar.


Type of Solar Brief description
Large Solar

The growing number of Semi-Scheduled solar units in the NEM (plus a handful of Non-Scheduled units) have metered generation measured by AEMO and reported in real time through the MMS in the ‘Initial MW’ field.

Collectively, these solar farms are referred to as ‘Large Solar’

Medium Solar

‘Medium Solar’ refers to installations that are too large to qualify for the SRES scheme (i.e. above 100kW) but too small to be of individual interest to the AEMO sufficient to have live SCADA data fed into the MMS.

The Royalla Solar Farm (Max Cap = 20MW) is currently the smallest solar farm that has real-time visibility in the AEMO’s MMS.

Above 100kW but below (say) 20MW are a growing number of installations which operate invisibly in the electricity grid.  As such, these invisible solar farms are a form of Villain no 8.

This is particularly problematic as

Small Solar

On Friday 17th June 2016 we wrote about ‘The opacity of distributed, small-scale solar PV output’…. and we followed this up with a subsequent article ‘The (ongoing!) opacity of distributed, small-scale solar PV output’ on 2nd December 2019.

These articles talked about the ‘sample and extrapolation’ method used to estimate contribution from rooftop PV with two main variables used:

1)   An aggregate of some real-time samples obtained from several data aggregators (e.g. PVoutput and various others), scaled by the reported installed capacity of these individual systems; and

2)  Extrapolation using the reported installed capacity of all rooftop systems in that location (from the Clean Energy Regulator database of rooftop solar PV systems awarded SRES credits … so limited to under 100kW capacity).

Clearly this method is not perfect – but it is the best method available at this point in time.

We’ll continue this later…