Solar panels are devices which generate electricity from sunlight. There are various factors which affect this generation. Depending on these factors, solar panel’s electricity generation can vary vastly. In other words, the efficiency of solar panels increases with favorable factors and decreases with non-favorable factors. Cleaning is an important factor. This guide talks about how to clean solar panels, why is it necessary to clean them and how often should you clean solar panels.
The most important factor of the many factors that determine the efficiency of solar panels is “Cleanliness”. Cleaner the panels, the better will be the generation and vice versa. Various studies have been carried out all over the word on this topic. All these studies show that power generation can be doubled and even tripled by periodic cleaning of solar panels.
Why is it necessary to clean solar panels
To explain this, let us look at the solar panel structure (without going into much detail) in the figure given below.
You can see in the figure that, the topmost layer facing the Sun is cover glass. Then comes anti-reflection coating and then the top–metal contact. Below this, are solar cells where all the major action takes place.
Now, when hindrances such as dust, bird droppings, pollen grains etc. accumulate on cover glass of solar panels, the sunlight reaching the solar panels can’t get to the solar cells which generate electricity. The more the dust on solar panels, the less sunlight will reach solar cells and and consequently, power generation will suffer.
Even one dirty solar panel can affect the solar power generation drastically. This is because, dirty solar panel acts as a blockage in the entire series and reduces generation.
So, for the solar panel and consequently the whole solar plant to work at its maximum efficiency, all solar panels should be clean. I will call it both important and necessary.
So, let’s get started with how to clean solar panels
Unlike many important things, cleaning solar panels is very easy. It is just like cleaning any other glass window. Here, are a few factors you should consider before cleaning solar panels. Also, ways you can employ to clean solar panels and get best generation.
Time of Day: Solar panels provide maximum generation in the afternoon, mostly between 10:00 a.m. to 4:00 p.m. Nobody wants to disturb power generation in peak hours. Also, during these peak hours, especially in summers, solar panels become very hot in the sunshine. Considering both these factors, the best time of day to wash solar panels is either in the morning or in the evening. The best would be to wash solar panels either before 8:00 a.m. or after 5:00 p.m.
Using Wiper and Water: This is one of the easiest, cheapest and most employed way to clean solar panels. You can pour water onto the solar panels (either from hose or a bucket; although hose will be simpler) and wipe away all the dust and dirt on the panels with a wiper.
Using Mop/Cloth and Water: This is also one of the easiest, cheapest most employed way to clean solar panels. This is just an alternative of the above method. The method remains the same. Just pour water from either hose or bucket and use mop or a soft cloth to clean solar panel. This one and the one above are best cleaning options for small rooftop installations.
There are many different types of mops available in market at various prices. Some even have integrated water spray at its wiping brush. So, you don’t have to carry a separate bucket or hose all the time.
There are various automatic cleaning systems available for cleaning of solar panels. These are sophisticated cleaning equipment. These are used in large plants (generally, megawatt scale installations) and these can be very expensive.
How often should I clean my solar panels
Now, the question arises, How often should I clean my solar panels? The answer to this question varies from place to place. In dusty places like North India, you may have to wash your solar panels once in every one or two weeks. At more clean places, you may wash them once in two or three weeks. So, period of washing solar panels needs to be determined according to the various ambient conditions such as climate and pollution etc.
Various cases have been studied till date by various organisations to record performance improvements of solar panels after being clean. These studies show that, periodic cleaning of solar panels can increase the electricity yield from solar panels by huge percentages.