Shading can significantly reduce the efficiency of a solar panel system, with some experts estimating potential energy losses of up to 40% due to shade. This occurs because shadows reduce the amount of sunlight reaching the panel’s surface, directly impacting power output. However, there’s no need to worry—effective solutions exist to minimise or eliminate the effects of shading.
In this blog, we’ll explore how shading affects solar panels and discuss the best ways to tackle this challenge.
Solar panels are often connected in series through parallel "strings." If one panel in a string is shaded—by a tree, chimney, or other obstruction—the power output of all the connected panels in that string can be reduced to match the output of the shaded panel. This is because the system is wired so that the weakest-performing panel determines the performance of the entire string.
For example, shading a single cell in a module by half can cause the entire module’s output power to drop by 50%. In extreme cases, completely shading one cell can reduce the module’s output to zero, regardless of the number of cells in the string.
When installing a Solar PV system, it’s essential to consider different types of shading. Shading can vary by location and season, and at TJS Solar, we categorize shading into two types:
1. Dynamic Shading
Dynamic shading is temporary and caused by factors like moving clouds, falling leaves, snow, bird droppings, or dust.
2. Static Shading
Static shading is caused by fixed obstructions such as trees, buildings, chimneys, or satellite dishes. Because these are permanent, they can often be accounted for during system design.
Although shading can pose a challenge, it is not insurmountable. With careful planning and smart technology, its impact can be mitigated effectively. Below are some of the best strategies to handle solar shading:
By installing bypass diodes, you can isolate shaded cells, rerouting the current to “bypass” underperforming cells. While this prevents the shaded cells from affecting the entire system, it also means losing the output of the bypassed cells.
For better performance, you can use module-level power electronics (MLPEs) like DC optimisers and microinverters. These devices work at the module level to boost performance.
At TJS Solar, our advanced design software allows us to plan layouts that minimise shading impacts. Our experts account for factors like the time of day and year when shading occurs and its duration. A well-positioned solar array that experiences minimal shading during peak sunlight hours (especially midday in summer) can achieve optimal performance without requiring additional solutions.
In a traditional series connection, shading on one panel reduces the performance of the entire string. By using parallel connections, you can isolate shaded panels to specific strings, ensuring unshaded panels operate at full capacity.
Microinverters further enhance this approach by connecting each panel in parallel, allowing them to function independently at their peak performance.
At TJS Solar, we understand that shading can be a critical factor in solar panel performance. That’s why, during our site surveys, we perform detailed shading analyses to identify and address any potential issues. By booking a free survey with our accredited team, you’ll receive expert advice on how to optimise your solar system for your property.
When considering solar panels, don’t forget to evaluate potential shading risks. Are there plans for nearby high-rise buildings? Does a neighbour's tree cast a shadow on your roof? While shading can be a challenge, it’s one that can be overcome with smart design and innovative technology.
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