How to calculate the generation in kWh of the PV Panels

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Bob Smith

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Hello everyone

I have this website I would like to share it seems it has not been shared here (at least I could not find it)


I only use it to estimate the kWh generated all the savings etc.... I am not interested it is missing information to be correct.
The estimated kWh is based on the rate of sunlight in your area and some characteristics of the installation

For information, I already have PV since 2016. As an average, they generate 3850kWh per year. The installer at that time has given me 3200-3400kWh.
The website finds 3360kWh.

I have done this check to see if I could rely on it or not to see how much additional panels could generate.

Does anyone know any other websites?

Thanks
 

binky

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find your roof pitch and orientation to south in the document below, and multiply by the size of your array. Unfortuanetly this site wont allow me to attach the full excel file as outputs will vary by region, but you can search this online.
 

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binky

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shade evaluation tool, this really needs to be printed onto acetate and placed in a little viewing holder, but if you curl it in your hand and squint a bit it should give you some idea, for every square that shading affects, you knock off 1%, so if shade affecs 10 squares, you knock off 10% from the annual figures.
 

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Bob Smith

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Thanks Binky, I have seen this diagram before. I did not realised you need it to print it out. I'll try

The website I provided the link has a parameter for the shade, It ranges from
<20%
20-60%
60-80%
>80%

It might not be as accurate as your diagram though.
 

Bob Smith

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find your roof pitch and orientation to south in the document below, and multiply by the size of your array. Unfortuanetly this site wont allow me to attach the full excel file as outputs will vary by region, but you can search this online.
OK thanks
 

binky

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Thanks Binky, I have seen this diagram before. I did not realised you need it to print it out. I'll try

The website I provided the link has a parameter for the shade, It ranges from
<20%
20-60%
60-80%
>80%

It might not be as accurate as your diagram though.
it's a rough guide, shading is also dependent on distance from the array, the further away it is, the more indirect / ambient irradiance you get so the less performance drop.

Also forgot tp say the official average outputs are also out of date, panel efficiency has improved since that was constructed, so you can expext to do better than those figures.
 

Bob Smith

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find your roof pitch and orientation to south in the document below, and multiply by the size of your array. Unfortuanetly this site wont allow me to attach the full excel file as outputs will vary by region, but you can search this online.
Did you try the website I have found?
 

Bob Smith

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it's a rough guide, shading is also dependent on distance from the array, the further away it is, the more indirect / ambient irradiance you get so the less performance drop.

Also forgot tp say the official average outputs are also out of date, panel efficiency has improved since that was constructed, so you can expext to do better than those figures.
I agree on both points
and it will depend if the shading is cause to a tree 20m or 100m away or a building.

For your second point, I have considered that point because I am lucky enough to be able to check the calculation with real figures based on 6 full years.
If I am happy with the minimum or worst case scenario then I'll be over the moon with the real data :)
 

Bob Smith

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I have found another website but this one is very primitive


very little number of options and choices and it does not give the results in kWh
 

Bob Smith

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Another useful reference

https://www.inbalance-energy.co.uk/solar_pv_information_calculators.html.

This site contains a list of many websites that will help size up a new system, calculate the generation in kWh and much more. It is a lot more technical. It should provide references for most, if not all, what is needed to size a new PV system.

One website listed is this one


It looks like this

1659686282251.png
 
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