Poor Generation stats - what do I need to check / is this explainable?

I’ve had my system for a year now and it has only generated 4,432kW which is only 75% of the estimated. I have GivEnergy 5kW Inverter, Tigo optimisers & 15 415w Perlight Delta panels so 6.22kW total. I am in southern England and roof is South West facing with a slightly steeper pitch than average. I get some shading from neighbours trees in the late afternoon which definitely impacts performance.
Looking at the last few days with good weather I am getting 26-31kW per day with a maximum of 5.3kW in an hour. The maximum seems to be 15.30-16.00 or around then.
Looking at past months my daily maximums each month are 12th Feb 14kW, 3rd March 24kW, 30th April 29kW, 9th May 34kW & 2nd June 33kW. Spring performance is better relatively, probably due to lack of leaves on trees and potentially roof pitch vs peak summer.

And the weather hasn't been great...

There's a thread on another forum where people compare their monthly generation figures with the average (10 or 20 years, I forget which) data from pvgis data source. A lot of people have said it's their worst year since their solar was installed.

There's a site pvoutput.org where people can upload their generation stats. This is a good way to compare your system with others nearby.

APROPHET Your post is hard/impossible to understand! Please try to rewrite it with meaningful units. kW is instantaneous power kWh is energy.

APROPHET

I have started to look at my 13 year old system in more detail to understand if all is ok with it.

Some things to check.

Monitor your inverter readings of each string to ensure they are operating broadly in a similar fashion if they are evenly split.

So if each string has same number of panels check the volts and Amps are broadly the same at the time you check.

Ideally check them at peak operation, i.e when sun is the strongest and hitting the panels at peak - depends on panel orientation and when peak should be.

By doing this you should be able to see if panels are performing as expected at peak.

This has absolutely been the worst year for solar since my system went in. June doesn't look like it is going to be good either.

The joys of global warming...

mrand31 So sorry for the typo - kWh. Surely you understand what I am saying? Pedantic nonsense

As @TX200 says the weather hasn't been great this last year.
If you are getting shading in the afternoon then that's going to degrade your peak generation ability, but if you are getting over 5kW at what would be peak time for a SW facing array then you aren't being too badly affected by the shade.

Are you getting clipping in the afternoon when your generation reaches 5.3kW?
If so consider modifying your battery charge rate on sunny days so that it is still charging during the peak generation - that will allow your inverter to harvest more than 5kW in an hour.

Consider producing your own estimate from one of the many tools on the internet.

APROPHET I understood you.

This year so far has not been great. One point is that although your panels may be able to generate more than 5.3kWh once you have charged your batteries (if you have any) the max you will get is a 5kwh plus a bit from the solar. The GE inverter will have hit its limit at this point. This is what many will call "clipping"

There are things you can do to minimise clipping and gain the full potential generation.

APROPHET Surely you understand what I am saying? Pedantic nonsense.

Driving 115mph from London to Bristol will get you arrested. Driving 70 miles from London to Bristol won't get you as far as Swindon. Pedantic nonsense? Surely you understand what I am saying...

mrand31 but you did understand the original post, right? I mean everyone else did...
I bet you could even replace kW, kWh with unicorns or flowers and you one could still makes sense of what's what

Back on topic, @APROPHET are your Tigos connected to "the cloud"? If not, there is a kit that does that for around £100 and probably that would your best bet at seeing if / what is wrong with your system

dragos.balaban I had to read it three times to work out what @APROPHET was saying.

It's really not difficult to use the correct units , just as one does in other subjects.

M_J Is there an easy way to tell from the volts and amps figures whether the issue is with the panels or is with the inverter

Maxwell I hope to have time today to try and expound on my thoughts of how I can check performance. Mid day I will be in the attic reading the inverter to see what each string is inputting into the inverter.

My thoughts are you should be able to compare the specs of the panels with what is actually being generated at peak.

Today being a near perfect solar day with minimum clouds the panels should be at max. Of course heat might mess that up a bit...