Does shading impact solar panels?

If shading isn’t considered when installing solar panels, the efficiency of not only individual solar panels being shaded, but the whole solar array can be reduced. According to several studies, shading on solar panels can reduce the array efficiency by as much as 40-50%, impacting the amount of electricity produced and therefore the potential savings. Even with just 10% of a single panel being shaded, this can reduce the panel efficiency by as much as 50%. With considerate planning at the installation stage, shading can be minimised, and the technology put in place to ensure the wider array isn’t impacted by potential shading.

Solar panels are typically connected in a series of strings, with each of the panels within that string only being as efficient as the least efficient panel within the string. As such, if any of the panels within a string is impacted by shading, all of the other panels within that string will only be as efficient as that shaded solar panel. As shading can impact the efficiency of a solar panel by between 40-50%, all the other panels within the string will lose between 40-50% of their efficiency.

Shading can be caused by several everyday circumstances such as clouds, dirt, leaves and bird droppings. There is very little that can be done to prevent these everyday types of shading; however, cleaning and maintenance of the solar panels will help reduce the impact this shading has on the solar panels.

Types of shading that are more troublesome for a solar panel system and should be considered during the installation process include shading from chimneys, trees, buildings and even satellite dishes. This type of shading can be considered, and the placement of solar panels can be designed to ensure shading either has minimum or no impact on the system.

• Solar panel diodes and microinverter

If shading can’t be avoided during an installation, utilising microinverters between panels will ensure that the deficit in efficiency isn’t passed on to the rest of the panels in the string. Another option is to utilise bypass diodes which will bypass any underperforming panels which will ensure they don’t impact other panels within the string, however, these underperforming bypassed panels won’t be contributing to the system output at all.

• System design and solar panel placement

If enough space exists at the installation location, avoiding areas where shading occurs is often the best course of action. This will ensure that all panels can always work to maximum efficiency.

• Group of strings - shaded and non-shaded strings

If shading can’t be avoided during the design/planning and installation process, grouping panels into strings that are both shaded and unshaded will ensure that only shaded panels are impacted, and panels that aren’t impacted by shading are kept within a separate string to allow for maximum efficiency.

• Bird Proofing

Ensuring that any panels have the appropriate bird-proof mesh is important to reduce the chance of birds nesting underneath the solar panels. Once birds nest under the solar panels, typically there is an increased chance of bird droppings on the panels as well as an increased fire risk with the various nest debris under the panels.

• Maintenance of solar panels

Ensuring that the panels are periodically cleaned will remove any excess dirt or dust that can build up on the panels over time, causing a barrier that will reduce sun light reaching the panel.