subject: The Effect of Shading on a Photovoltaic Array [print this page] Copyright (c) 2010 Aaron DicksPerformance of PV Systems can be affected massively by the effects of shade and lower light conditions. Lower energy yields are gained when the PV system is not under optimum sunlight. This could be because of cloud cover, the effects of shade or partial shade, and even the incorrect installation angle. Due to the nature of Photovoltaic Cells manufacture and installation practises, they are wired in series.This means that the whole array will only be able to perform as well as the worst performing cell. Because of this, it is important that you have a specialist installer install the system, as they will be able to calculate the incidence of shade and ensure your system can perform to the maximum all year round. If one panel falls under partial shading, this can severely affect the yield of the system - especially when one panel could be a tile, as the percentage shaded by a small object would be a lot higher. Tiles, like panels are also wired in series to a grid-tied inverter. During winter, snow has the potential to build up on tiles, which will effectively render the panels useless unless they are brushed down. When dirt, leaves or snow does cover or partially cover panels, this should be removed as soon as possible. Due to the angle of installation, rain water or melt water will remove any debris. Not only is it important to keep your panels performing to the maximum because of your home energy supplies, but it is also an imperative measure to ensure that you benefit from the United Kingdom Feed-in Tariff. Panels can be mounted in various methods - on roof, in roof, and on the ground. On roof systems are installed on a mounting system, raised off of the roof by brackets which sit on the roof rafters behind the tiles. This is an ideal method of getting a system fixed to your home with little disruption. Any domestic properties can have an installation within a day. In roof systems are generally utilised when a building is being re-roofed, or on new build installations. They sit at the rafter level in between the tiles or slate. Generally, tiles would be used in this situation, as they look cleaner; however there are methods of mounting panels amongst tiles, which look very clean and professional. Ground mounted projects are generally for larger installs, such as commercial, farm owners and land owners. By using a large amount of panels, it is possible to gain large returns through the feed in tariff.
