What the Guru says
Hi Solar Guru – will solar panels still work ok in shade? I do not want to cut down my lovely trees.
Well, they are not called Solar Panel for nothing. The more sunlight there is on your solar system the better it will perform and the longer it will gong to last, because it is not under stress.
However in the real world a lot of solar systems are shaded these days. if your house is shaded and you are getting a new solar system there are new technologies and new inverters that can help you to optimise the output of your solar system.
So do not worry, you can still do it - but just make sure your solar installer has really done their homework and has chosen the best technology you can get to take into account your shading.
Solar and Shade – the Ying and Yang of renewable energy
Solar panels do need the sun to generate the most renewable energy. They do generate electricity even in shaded conditions. But their performance is significantly reduced compared to when they receive direct sunlight. When it comes to shade, there is the shading of just 1 panel, partial shading of the system, or strong shading most of the time. You can find a detailed FAQ question on this matter here.
Here are a few critical matters to be aware of
Partial shading
If only a small portion of the panel is shaded while the rest remains in sunlight, this is called partial shading. The overall result of a PV panel’s performance by partial shading is that the impact on system performance may be relatively minor. However, it’s important to note that shading even a small area of a solar panel can reasonably affect its output.
Panels connected in a string
Solar panels are connected in series e.g. plus DC connected to minus DC connector. This creates a higher voltage in the string and starts the electron flow. In a string inverter setup, if one panel is shaded, it can significantly reduce the performance of the entire string of panels. For this reason, especially if you have a string inverter. It is essential to minimise shading on any part of the PV system.
Inbuilt panel shade protection
Modern solar panels have half-cut cell technology, meaning if there is shade at the bottom of the panel. The top half will still produce well, and the shade only leads to a 50% loss of output. Panels also feature bypass diodes, which also assist in dealing with shading. These diodes allow the current to bypass the shaded portion of a panel, minimising the overall power loss. Bypass diodes that are exposed to strong shading year in and year out can suffer fatigue and fail. Leading to actual panel failure, as they now lack protection. Usually, such failure is not covered by the panel warranties.
What technology to use when shade is an issue?
You might have already heard that microinverters or power optimisers offer a solution in case of a roof with shade issue. This technology will add to the cost of the system overall but is, in some instances, the only option to generate a worthwhile solar power system. These small devices are installed on the back of the panel, on the roof, not on a wall-like string inverter. They allow each panel to operate independently. So if in a group of 20 panels, 3 are shaded – the other 17 are not also reduced, like in the string inverter technology, but power away full throttle.
What else can you or the solar installer do about shading?
If close trees cause the shade, see if cutting back any branches can assist. Trimming trees strategically can reduce the amount of shade and improve the system’s performance. Alternatively, you could explore relocating the panels to an area with less shade, such as another part of your roof. Not much can be done if the issue is a neighbouring building. On the other hand shading from plumbing pipes, antennas, or satellite dishes can be minimised via relocations or a smart choice of panel location on the roof.
Ultimately, we all need trees to generate oxygen, so we do not suggest cutting down trees to improve solar performance. It’s important to strike a balance between preserving your trees and optimising solar panel performance. Consulting with a professional solar installer can help you assess the shading situation and determine the best solution for your specific circumstances.
