Maintenance services

Lichen on solar panels

Lichen is a term used to describe a composite organism that consists of algae living in a symbiotic relationship with a fungus. This relationship has advantages for both and allows them to flourish in areas where many other organisms are not able to establish themselves. This ability to withstand harsh circumstances allows lichens to grow on solar panels, reducing the amount of light that hits their surface and causing concentrated 'hot spot' damage. If left unchecked, this damage will eventually lead to solar panel failure so it is essential to remove any lichen frequently.

Lichen on solar panels

The lichen family’s ability to enter a dormant state for long periods of time when water is unavailable and then to recommence growth once conditions improve enables them to grow and flourish in areas where plants can not.  This includes the surface of solar panels, where the microscopic pitting in the glass surface allows the organism to fix itself and create a base from which to spread.

This characteristic ability of lichens to attach themselves firmly to a surface at a microscopic level, combined with the facility to enter a dormant state almost indefinitely is what makes lichen so difficult to remove fully.

Lichen copy

Effect on solar panels

Anything that obstructs light from reaching the surface of a solar panel will reduce its output. This effect can be more pronounced than expected because modules are constructed with series circuits and strings of panels are also co-dependent in many instances.  If one module’s generation is reduced then this will cause a knock-on effect for every module in that string, meaning that a small amount of shading can cause a magnified reduction in output.

DSC_2483Over the longer term, if an area is shaded for an extended period then this can cause what is known as “hot spot” damage.  This is a far more serious issue, since hot spot damage will eventually cause a module to fail completely.  It is mainly for this reason that removing lichen is extremely important before it creates a serious problem.


NWT use specially designed chemical treatments and powered brushes to kill and remove the fungus and algae that combine to cause lichen growth. If there is a lichen problem with your system we will contact you to discuss removal options.

Although the process is more time consuming than standard panel cleaning, removing lichen will increase your electricity production and protect your system from further damage.