London City Bond has 250kW of solar PV spread across a vast area of its roof surface in blocks. These mounts allow the panels to face South, which means that they will generate more electricity over the course of a year, and also mean that the clear roof sheets are left unobstructed.
This also makes them difficult to reach given the large distance from the edges. Nonetheless NWT’s cleaning and maintenance unit were able to access all areas of the installation using dedicated 100m hoses attached to the rotating cleaning brush heads
Over time, almost all solar panels will have accumulated a layer of dirt, but this happens more rapidly when they are mounted with a shallow pitch or positioned in a particularly dirty environment. In this case the site is on industrial land in the Thames Estuary, which has quite a lot of airbourne dust and also suffers from higher-than-usual bird droppings.
Using the QLEEN rotating brush system we were able to remove the entire layer of dirt and substantially improve the performance of the system – up in this instance by more than 10%. Cleaning PV panels properly should be undertaken at least annually to ensure that you continue to receive the correct amount of income from your system.