Solar panel shading
If you are deciding if solar is worth it and, your rooftop is subject to shading, then you need to understand that shading can affect the performance of your panels considerably. You also need to know that there are solutions.
How shading affects panels
A solar power system is normally split into strings of panels; a small system can consist of one string, or it may have multiple strings. If one panel or part of a panel is subject to shading, the output of that string can be eliminated. The effect of solar panel shading can be difficult to calculate because you need to determine how much of your system is likely to be subject to shading.
Solar shading issues should not necessarily deter you from installing solar panels. Even if your property is subject to shading for up to two hours per day, there may still be benefits to installing solar, especially if you do not typically use electricity during the hours of shading. If your property is subject to partial shading, there are some excellent solutions available.
What causes solar panel shading?
Nearby buildings, trees, branches, chimneys, fallen leaves and other debris are all causes of solar shading. While fallen debris may not be classified as shading as such, it has a similar effect on the output of the solar panels.
Solar shading solutions
Avoid shading where possible
The best way to mitigate against solar shading issues is to eliminate them. Consider installing your solar system in another location on your rooftop that is not affected by shading.
Address shading issues at your property
If your rooftop is subject to shading from a tree or the branch of a tree, it may be possible to remove the offending limb.
Partial shading of your solar array can be mitigated with microinverters. Microinverters allow each solar panel to operate independently of the panel adjacent to it. They do not operate like a typical string inverter, so if one panel is subject to shading, the other panels will still generate solar power.
- Adding microinverters to a system can add to the overall cost of installation by as much as 20%.
Power optimisers are small boxes that are attached to the back of each solar panel in a system. Power optimises combat solar panel shading by eliminating the power mismatch between solar panels in a string. Solar power optimisers are similar in many ways to microinverters; only there are two key differences: they can work in conjunction with string inverters, and they are far more cost effective.
Purchase high quality, advanced panels
It is also possible to minimise the effect of shading by purchasing technologically advanced panels. The Maxeon cell technology in SunPower panels reduces the loss of output through shaded cells. SunPower panels are also highly efficient in unshaded conditions, but they are at the pointy end of the market in terms of price.
Ask your installer
A good solar installer company should be able to perform shade mapping for your rooftop to determine the impact on the system production. The installer can then design a system that minimises the effect of shading. If you are