Solar Panels and Shade

Shading can have a big effect on the performance of your solar power system. The amount of shading and the time of day may determine whether it is worthwhile putting solar panels on at all. Small amounts of shading at the start and end of the day may have minimal effects on output due to the losses being imposed on a reduced initial output. Ideally you want to have clear access to sunlight during the middle of the day between 9am to 5pm. Clouds will reduce the output of your solar system, but the panels will still receive dispersed light, its direct shading from trees, vent pipes and other objects that are of most concern.

Below is an example of electricity flow in a solar panel affected by shading.

The best way to assess the impact of solar on your rooftop is to have a shade analysis done. Green Energy Options use a SunEye to assess the impact of shade on your rooftop. The SunEye is a professional tool that takes a photograph of the surrounding objects through a fish eye lens, it then lays a sun path chart across the image showing the time of day and time of year that shading affects the location being assessed. The impact of shading for each month of the year is then calculated. We include the shading report in our estimates on your solar system’s output giving you an indication on how we expect your system to perform. Generally once you get above 10-20% of shading you need to consider if the solar system is going to have the effect that you intended, our aim is to put you in a position where you can make an informed decision.

 

SunEye Shade analysis

SunEye Shade analysis

It is important to be aware that in a standard solar system with a string inverter and 10 panels, shading on one panel can have a “weakest link” effect on the rest of the array, reducing the output of the whole string of 10. One option for reducing the impact of shading is to use micro-inverters. Micro-inverters individually optimise the output of each solar panel, so that shading on one panel doesn’t affect the output of its neighbors.

 

Shading micro-inverter vs string inverter

Shading micro-inverter vs string inverter

Image courtesy of Greenstar Micro-inverters

Green Energy Options can provide a detailed shade analysis of your site as well as options for both string and micro inverters. Give us a call to find out how you can go solar 1300 931 929.