Pv kWh produced vs installed capacity. How's yours doing?

[Scrambler]

I have 25 kWh of solar pv on a south facing 15 degree pitch barn roof. It's just had it's 7th anniversary and produced a total of 172195 kWh. That's 984 kWh per year per 1 kWh installed capacity. That's at the top end of where I hoped it would be, but they have produced about 6% less the last couple of years than they did in the first 5.
It would be interesting to know how others are getting on.

 

[f0ster]

have you ever had to clean them? a 50kw install we were at adding an extra couple of strings was very soiled, the new strings were giving out more then double the existing strings.

 

[Scrambler]

They’ve never been cleaned. That’s one of the reasons it would be interesting to compare. I think a certain amount of degradation is to be expected.

 

[akaPABLO01]

Depends on string cable size. You get 2mm (2/4kW) 4mm and 6mm

I always put 6mm on anything above 4kW and never used 2mm. Makes a big difference.

 

[Exfarmer]

Be aware that annual output can vary quite a bit year to year. We are only into our 6th. year but have noticed significant differences. However I think you should have a close look at them to see the level of dirt build up. If you ask around local window cleaners hopefully if the panels are not too difficult to access , you may find one with a long pole to clean them. they must use pure water but many are geared up for that. However you will not see a vast improvement unless the panels are very dirty.

 

[curlietailz]

Mine is an 2x4kW domestic arrays. In their 5th year. I’m very happy with the performance so far. Never washed or cleaned them.

 

[upnortheast]

Ours 30 kw system has been running 4 years this week
Total 112970 - so 941 kw installed / year. About 1000 kw / year higher than the installer`s prediction
Never cleaned, doesn`t show much sign of needing it