First Year's PV Performance

[NSS]

Our 4k solar PV went live in mid-January 2016 so I now have the total kWh generated in the first year @ 3,340 kWH. Our system has 2kW @ 084^o, 0.855kW @ 174^o and 1.14kW @ 264^o (roof angle is 42^o ) so we get a reasonably good yield across daylight hours, the aim being to generate power when we're most likely to be at home using it rather than generating the max possible (by having it all south-facing) but using much less of it. This is particularly important given the comparatively low FiT rate we get (we only get the lower rate as there was no EPC when the system was commisioned).

 

Anyway, the reason for this post is that I am wondering how our output compares to that of others with 4kW installations? I know location will influence others' results, but would appreciate if some of you could post your total kWh generation (and array size/orientation) for the last 12 months, please.

[ProDave]

Highlands, near Inverness.

 

2KW system, been in use 5 years. Total so far 7565KWh, so an average of 1513KWh per year. So your 3340 for 4KW being further south sounds about right.
 

[NSS]

5 minutes ago, ProDave said:

Highlands, near Inverness.

 

2KW system, been in use 5 years. Total so far 7565KWh, so an average of 1513KWh per year. So your 3340 for 4KW being further south sounds about right.
 

Cheers Dave.  I should have mentioned we're on the South Coast. 

[AliG]

My 4K system has been generating around 3.1kw a year since installed. Unfortunately the figures are a bit messed up due to the meter breaking for a few months in 2015 before I noticed.

 

Recently has been the best period of production. I generated 2920kWh between 7 March and 18 November 2016.

 

I'm in Edinburgh and it faces almost exactly due south at 45 degrees.

 

 

[Ferdinand]

I was wondering about reporting on this.

 

I received my first 95% of a year report recently, and we did a total of 4068.5 kWh, on a 9.98 kWp 80% east / 20% west system installed Jan 2016, with a total payment of £541 pus whatever we have saved by using self-generated electricity, which I estimate at another £150.

 

The meter reading this AM came out at 4093.3 kWh.

 

All that says is that it will pay for itself eventually, and the results are seriously mucked up because more than half of it was behind trees for months, and some of it is still behind trees :-). The contingencies of meeting dates for subsidy !

 

Previously I predicted about 5500kWh, but there is considerable environmental finessing still to be done, which may involve our other neighbour's TPO trees which are looking a little dodgy and may be towards DDD (Dead, Decaying, Dangerous) condition. For a substantially better result

will need to finesse some (perhaps 10-12 for a 16 / 12 / 8 ESW mix) of the panels onto a south-facing carport roof which only exists in my head at present. But that will need care to keep an attractive 'face' on the house.

 

Ferdinand

 

Edited January 16, 2017 by Ferdinand

[jack]

We have an 8.5kW array on two sections of flat roof on the Hampshire/Surrey border.  About 40% of them are facing directly south at a fairly shallow angle.  The remaining 60% are in a flat east-west concertina shape with a very slight tilt towards the north.

 

There's some morning shading throughout the year.  We went for Enphase microinverters following modelling that showed how much more power would be generated.

 

This is the summary from about half an hour ago:

 

 

It's dull and rainy here this morning, so I'm surprised we even have that much being generated.

[Barney12]

Our Phase 1 PV went live on the 22nd July.

 

South West England

 

Batmoral Array: Facing South East (ish. More East than South!). 1.5kw.

Total generation: 472kwh

 

Cluckingham Palace and Recycling Center Array: Facing South: 1kw.

Total generation: 278kwh

 

[TerryE]

14 hours ago, NSS said:

Our 4k solar PV went live in mid-January 2016 so I now have the total kWh generated in the first year @ 3,340 kWH. Our system has 2kW @ 084^o, 0.855kW @ 174^o and 1.14kW @ 264^o (roof angle is 42^o ) ... I am wondering how our output compares to that of others with 4kW installations?

 

Out of interest have you compared this to the PVGIS prediction for your configuration?

[NSS]

1 hour ago, TerryE said:

 

Out of interest have you compared this to the PVGIS prediction for your configuration?

 

Hi Terry, the PVGIS predicted output was 3,276 so we've actually done very slightly better than projected in the first year.

[SteamyTea]

The UK had a brighter than usual year last year, unlike 2012 (I think), when it was unusually dark.

[jack]

Wasn't 2015 pretty dim too?  I seem to recall people talking about day after day towards the end of the year with zero production!

[SteamyTea]

You can get the data here, if you ask nicely.

https://badc.nerc.ac.uk/data/surface/radt_file_format.html

I don't have time to look at it at the moment.

Edited January 16, 2017 by SteamyTea

[bassanclan]

Our system was installed in mid Jan 2016 too:

 

16x250w 8.33 eternity moncrystalline (4kw system)

 

35 degree roof pitch

30 degrees from south

shading factor 1

zone 6 Birmingham

 

Predicted: 3648 KWH

Actual: 3337 KWH

 

Not as much as I had hoped for, but not terrible and certainly worth rushing to get in before the FIT cuts

[TerryE]

1 hour ago, NSS said:

the PVGIS predicted output was 3,276 so we've actually done very slightly better than projected in the first year.

 

Neil, even if the model was totally accurate, you would still expect 5-10% variation from the predictor year to year.  That the actual is 2% above the PVGIS to me underlies my view that this is a reasonably good model / predictor of solar radiance on surfaces. 

 

Thanks for this.

[SteamyTea]

Quick chart to show the variation of solar radiation over a few years.