Shading of the Solar Array

Include a shade analysis when doing a site assessment.

Shadows reduce solar production

Passing shadows  reduce the productivity of a solar array. Shadows are cast by trees, buildings, passing clouds, falling leaves….but we love trees!

If there are shading concerns, we include in the site assessment an analysis using a “Sun Eye” or similar device. Its report will accurately forecast the monthly energy shortfall.

Nowadays most central inverters have 2 inputs so at worst half of the array would be affected until the shadow passes.

We recommend micro inverters or Optimizers to minimize loss when shading is an issue.

Both maximise the efficiency of individual panels by their MPPT technology. (Maximum Power Point Technology).

Optimizers are small devices attached to every solar panel in the array and have the effect of bi-passing the affected panel or panels so that the remainder of the array is not affected by the shadow. 

In some cases just a few optimizers can be placed on modules directly affected by shading.

Optimizers are usually  more cost effective than microinverters.

Central Inverters at ground level teamed with optimizers on the roof reduce the need for workmen to climb on the roof, saving wear on shingles.

Micro- inverters and optimizers both perform the additional function of maximizing production of the individual solar panel by their MPPT algorithms and can add 5% productivity to any array even without shading. They both  provide web based monitoring of individual panels and useful reports.

Its addictive to view either on line display to see how the show on your rooftop is displaying and to compare production between months or years.

We have had good results using Solar Edge Central Inverters with Optmizers. Here’s a link to their website:

www.solaredge.com/us/

The original microinverter is Enphase. Here’s that link: www.https://enphase.com/en-us/residential-solutions

Either solution brings more on line fun than plain vanilla reports from central inverters can provide as the homeowner can view on line how each solar panel is functioning.

 

Author: MarkO

More than 12 years experience with home solar installation and sales.

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