The Australian national grid stretches from the tropics to the cold temperate zone from 16S to 43S. You might think that along those 40,000 kilometers of transmission lines there is always somewhere somewhere sunny at midday, but some days you’d be wrong.
James Luffman at WattClarity, noticed this extensive cloud arrangement affecting solar on Friday May 19th. On that day, a one thousand MW generator wasn’t there when it was expected to be.
Cloud patterns on Friday 19th May 2017 – leading to a day of low Solar PV output, NEM-wide
By James Luffman | Published Fri, 25 August 201
Cloud cover over Australia, map, preventing solar PV generation.
How often does this happen? Hard to say, since data on rooftop PV has only just started to be released. It may not be as often as wind turbines, which simultaneously flounder across the whole Australian grid every 10 days or so.
This kind of comma-shaped band of cloud is relatively common over eastern Australia, when you have moisture from the Coral Sea area feeding into a trough with a low-pressure system near SA or VIC.
In this particular case of 19th May, the band of cloud happens to cover most of the populated areas of the NEM, and the cloud is very thick over a large area. Being a widespread and slow-moving cloud feature, it shows up as a significant outlier in Paul’s daily aggregate graph, since it lasted most or all of the day over most of the NEM’s installed rooftop PV.
We should be grateful solar made it (nearly) to half its normal power:
….
Imagine if a coal plant was forecast to produce 2GW (only at lunch time) but some days, randomly, could only do half?
Would forward markets pay more for this energy?
ABOUT SOLCAST: Nick and Paul McArdle (WattClarity): started Solcast to assist with the integration of increasing solar PV into power grids, in association with a research project at the ANU led by Nick.