Solar Analytics identifies cloud of doom
On Friday 22nd of November 2019 Solar Analytics identified an unprecedented weather event in Sydney. As it turns out it was a unique opportunity to test our advanced algorithms and notifications systems across a vast number of customers.
Around 2.30pm, a huge weather system started rolling across the Sydney basin from the west and joined forces with significant smoke from the Gosper bushfires burning northwest of Sydney.
The intense storm cloud and thick smoke blackened Sydney’s sky bringing about a sudden and significant drop in solar insolation. Affectionately named the ‘cloud of doom’ at Solar Analytics HQ, it was so dark and formed so quickly it looked like the sun had set suddenly.
At 5pm, approximately 1,000 Solar Analytics affected customers and their installers started being notified that their solar system output had dropped to zero (Zero Generation fault). This means solar production was outside our normal expectations for this time of year at that time of day.
The sun did reappear briefly around 7:30pm before setting. For some systems that was enough to register the end of the zero generation event. Others resolved the next morning when production resumed with the rising sun.
The animated image below shows the event occurring between 3.05pm and 4.15pm. Each dot is a solar system with Solar Analytics monitoring. The colour scale (0-20) is system output in Watts.
Note the red changing to purple as solar energy production drops suddenly over the hour as the cloud closes over.
What is a zero generation fault?
A zero generation fault is when we detect that your solar PV system is not producing any energy at a time we expect that it should be.
Most of the time there is no danger associated with zero generation but our job is to let you know that you aren't getting the full value from your panels and that something may be wrong - so that’s exactly what we did.
In this case, the cause was an abnormal weather event and there was no cause for alarm.
This caused consternation for some system owners and we heard from a number of solar companies on your behalf. For those who looked at their system sites on the Solar Analytics dashboard the next day, it was apparent that their valuable solar production returned, and their system was operating as it should.
Often a zero production fault is caused by a circuit breaker tripping or your inverter shutting down due to high grid voltage or other problem so we do take zero production faults seriously, on your behalf.
Our sophisticated algorithms can detect the difference between cloud cover and a true zero production fault. When it is cloudy, your solar production normally slowly dwindles as the cloud comes over, with the occasional spike when some sun sneaks through.
The graphs below show the sudden drop of generation at one Sydney PV system site at around 2.30pm and a complete shutdown by around 4.30pm. Compare this to the day before where the system was producing around 4kW at 2.30pm and continued generating right through to almost 7pm.
Confluence of events
These storms also created a second event on energy networks around the Sydney basin and Ausgrid reported that around 20,000 homes lost power on the same day.
As we write this (Wednesday 27th November) 51,000 Sydney residents are again affected by weather-related network outages and, further afield, other parts of the New South Wales network are impacted by fires.
As a result, some Solar Analytics customers in Sydney and New South Wales may have also experienced power outages as a result of network issues and received notifications in addition to our under-performance alerts.
A word of thanks
We are grateful to the solar companies we work with for the prompt attention they gave in responding to emails and calls from customers. This is an example of the Solar Analytics’s analysis and support ecosystem functioning as it should to provide constant oversight of your investment.
We constantly review our algorithms and communications so that events such as these are more easily understood. This highly unusual weather event will help us enhance our service and continue to provide you with the most accurate information about your system’s performance available through any monitoring service.
As Rod Grono from Western Sydney Solar wrote to us on Saturday:
“Many of my customers got the system down email after 4pm today which caused a bit of panic and I had to do a bit of reassurance.
I'm happy with this as it helps reinforce the fact that Solar Analytics and Western Sydney Solar are ready to support our customers.”
Nice work Rod!
With warm regards
The Solar Analytics team