Modern solar panels have been innovated to work well in both perfect and poor lighting conditions. However, shade does still have certain impacts on their efficiency. Understanding how shade can affect your solar systems is a good way to make proper improvements so that you can exploit their benefits to the most.
Sources of Shade
Finding out common sources of shade that affects the solar system can help you come up with correspondingly feasible solutions to this problem.
Clearly, trees growing within the vicinity of solar array can be a leading factor to shading. Many households are now located in green spaces with tree planting being paid much attention to. Thus, you may risk having solar panels covered by growing trees and foliage during their 25-year average lifespan.
When it comes to sun angles and periods of shining, several parts of the roof may become a matter. For example, chimneys or dormers can block sunlight from reaching certain panels.
Clouds undoubtedly act as a blockage to sunlight, but they still allow a specific percentage of sun rays to pass through. Thus, the solar system can still produce energy at a lower efficiency than usual.
No wonder the fast growth of tall buildings in densely-populated areas has certain effects on the production of solar systems. Someone may build a house right next to yours that doesn’t let sunlight reach your panels.
In addition to trees and roof, solar panels are likely to be shaded by nearby ones. Panel installation can subject lower panels to being cast shadow over by neighboring panels in the same system. This is often the case as for ground installations.
Effects of Shade on Solar Panels
Shade Can Reduce Solar Systems’ Efficiency
A solar panel is constituted by separate solar cells, which are connected in a series string. Because of this, even if the smallest segment stops working under the influence of shade, the performance of the whole system will suffer. The weakest cell tends to bring others down to the same performance level.
While some cells cease to operate, the rest continues to run. Therefore, if there are 30% of cells covered by heavy shade, the pane’s total energy production will decrease by 30% in comparison with normal operation in full daylight. The longer duration a panel remains in shade, the less power it can produce.
Shade Can Shorten the Lifespan of Solar Panels
Like other electronic devices, solar panel cells’ high sensitivity doesn’t allow them to remain completely intact after being constantly switched on and off. In case some cells stop working, other cells in the same panel will have to work harder in compensation for the lost energy. Thus, compared to those in shade, such cells run higher risks of burning out due to overheating, getting the lifespan shortened. Even in full sunlight, those panels suffering from damages caused by shading are found to underperform.
In the long run, it may cost you great expenses of frequent maintenance or replacement for a better system. Besides, the discrepancy in power efficiency between non-shaded and shaded parts may add up to the reduction in the total energy output of the system.
Tips for Improvement
Install solar systems in shade-free locations should be the ideal solution, but this is not feasible in every case. You can change the structure of your house roof; calculate the number of sun rays reaching the system, or trim tree branches but not control the appearance of clouds. Alternatively, there are several ways to minimize the effect of shade on your solar systems.
Linking cells in the solar system, bypass diodes are used to restrict the amount of power lost in the shaded part in comparison with the whole panel. They create another route for currents flowing from the non-shaded part instead of passing through the shaded. This may cause a slight decrease in the amount of power due to the voltage drop, but as a whole, the output remains higher than power produced without the bypass diodes. Moreover, when panels don’t be covered by shade anymore, these diodes are automatically deactivated to protect the solar system.
The advent of micro inverters has marked the innovation of solar system technology. While conventional systems use only one inverter for the entire panel array, the inverter model equips each solar panel with a micro inverter. If one panel is blocked, others will still operate at their peak efficiency. This helps to produce more energy, minimize damages caused by outgoing high-voltage DC electricity and monitor each panel’s performance at will.
Power optimizers are similar to the combination of micro-inverters and string inverters. On the contrary to micro-inverters, they condition the DC electricity produced by each panel before transmitting it to a string inverter. As a result, they are helpful in preventing non-shaded panels from adversely affecting the entire system.
Maximum Power Point Tracking
MPPT, or Maximum Power Point Tracking, has become a must-have in any quality inverters. It serves to track the output of every panel and average them out. By this way, panels’ capacity can be assured even if they are covered by shade. This is simply due to their drop to below the output threshold.
Inverters with no application of MTTP technology may risk getting the energy from weaker strings lost when dipping below the preferred threshold.
Generally speaking, shade can expose solar panels to a reduction in operational efficiency and damages unless their designs include internal protection. Thus, it is important that you take proper measures to minimize those adverse impacts promptly. Refer to tips above, and you can lengthen the solar systems’ lifespan while saving a great deal of repairing cost. If shading is unavoidable, bear in mind to go for the right kind of solar panels.
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