Maintenance services

Cleaning Demonstration & Performance Boost

Testing the effectiveness of solar panel cleaning is not always straightforward because no two days will provide exactly the same conditions. Any increase in production could simply be attributed to more sunshine. Our site manager Gary Haines took the opportunity to test two strings of a ground mounted array under identical conditions whilst it was awaiting relocation on to the roof of a newly erected agricultural building.

Cleaning Demonstration & Performance Boost

Dirt builds up on the surface of solar panels over time, reducing the amount of light that can reach the panel surface.  Periodic cleaning is essential to maintain peak performance of a system.  This series of videos shows the difference cleaning makes whilst all other conditions – the irradiation, pitch, orientation, temperature, inverter etc. – all remain the same.

Solar PV arrays are generally connected in “strings” which comprise a number of individual modules linked together and then connected an the inverter.  By comparing two such strings we can get an idea of to what degree performance improves.

Using the dirtier string of 19 panels as a “control” group, Gary was able to quantify the impact that the cleaning equipment had made.  Using testing apparatus it was possible to measure the exact voltage and current of both strings, under exactly the same conditions.  Here you can see some of the specialist cleaning equipment NWT use in action, followed by the test of the cleaned string.

Switching over to the other string, with exactly the same number of identical panels in the same location & at the same orientation, we can see there is a reduction in the output, despite the fact that there was only a comparatively modest amount of dirt on most of the panel surface.

This difference in output will have a marked effect over time, and will be multiplied across all of the strings in the array.  With a Feed-in Tariff agreement lasting 20 to 25 years, these kind of discrepancies will have a substantial impact on the amount of electricity your solar PV system generates and how much revenue you achieve from it.

Test Comparison

How often solar panels need to be cleaned will depend on site-specific circumstances and the amount of particles in the air, as well as the presence of wildlife.  If the surface dirt is allowed to build too much it becomes difficult to remove it effectively, meaning the work takes longer and therefore costs more to rectify.  As a general rule, we recommend cleaning your system at least annually to ensure robust performance.

Contact us for a free consultation to discuss how NWT can ensure that you are getting the most out of your solar PV system.