One of the most important things to think about when installing solar panels is roof shading.
Shading can significantly impact the amount of electricity your solar panels produce. It’s why it’s critical to understand how much of your roof is shaded and how that will affect your solar output.
It’s also crucial to understand how to overcome shading issues and maximize the output of your solar panels.
How Much Could Shading Effect Efficiency?
Shade could be causing homeowners to lose up to 40% of their solar PV installation’s potential production, according to some experts. It isn’t because the entire panel is sitting in the shade, either. According to some statistics, just 10% shadowing of a solar PV panel can result in a 50% reduction in efficiency. The reduction is due to the way an array of solar cells is connected within the system.
Solar panel arrays are traditionally connected in a series of parallel ‘strings.’ If one array is shaded, the losses are passed on to the rest of the cells in the chain. Bypass diodes are frequently included in the installation to prevent all of the cells from failing altogether. The current is then rerouted to avoid the underperforming cells. Despite preventing the array from failing completely – similar to how a set of Christmas tree lights turns off when one bulb burns out – it limits the cells’ energy and lowers the string’s voltage.
The inverter must choose between optimizing the voltage for the underperforming string and maximizing the energy captured from the strings that haven’t been affected. In any case, the inverter will be forced to choose one of the two inefficient options.
Causes of Shading
Roof shading can be caused by a number of different factors, both natural and man-made. The following are the most likely culprits when it comes to throwing shade on your solar panels.
Trees: The most noticeable and ubiquitous source of shade are trees. While trees are beautiful to have surrounding your home, they might interfere with solar panels. The shade cast by these trees can prevent sunlight from reaching your panels, resulting in a significant reduction in their energy output. This shadow can be as little as a branch or two, or the entire tree may be shadowing the whole roof.
Solution: To make room for more sunlight, trees might be pruned or cut down. While you may worry about the environmental impact of cutting down trees , it may still be a feasible idea. A 25-year solar installation can offset more CO2 than the average tree can ingest. In other words, removing trees to make way for a solar system may reduce your carbon footprint.
Buildings: Other structures can also provide shading on your solar panels. These can be structures on your own property, such as a barn or shed, or structures on the property of others, such as houses or commercial buildings.
Solution: Building shading can be a little more difficult to deal with. If the structure is on your land, you can either demolish it or modify it so that it no longer blocks the sun. If it isn’t on your land, you may need to reconsider your solar panel placement.
Obstructions: Obstructions on the roof, such as chimneys, skylights, vents, and even other solar panels, can provide the final type of shadow. The amount of shading caused by these impediments may not be as severe, but they can’t always be easily remedied.
Solution: Roof obstacles don’t usually produce a lot of shading problems. Vents are generally thin enough that they don’t cast a lot of shadows, or they can be redirected to avoid shading. Skylights are often small and provide little or no shading. While chimneys can be quite large, the panels are usually built around to reduce or eliminate shade issues.
Is Shading a Solar Power Deal Breaker?
It has been suggested that the impact of shade is sometimes overestimated, particularly during peak yield seasons. Because the sun is high and straight overhead, shadowing of well-placed solar PV panels on a property at midday and throughout the summer should be low.
With this in mind, shading is a challenge for solar PV that any potential customer should consider and investigate. Shading can take many different forms, only be an issue seasonally, and vary depending on the things that provide the shade.
It may even be avoided by taking measures such as avoiding the installation of panels on roof parts that would be shaded, removing trees, or even contemplating a ground-mounted system.
Ask The Experts
Request a solar analysis from a solar panel specialist if you’re not sure whether your roof is too shadowed for solar panels.
The solar expert will likely take satellite photographs and analyze the amount of shade your roof receives using modern solar analysis equipment. They can develop a personalized solar study based on the collected information, which will illustrate where your solar panels can be installed as well as your estimated energy savings over time.
