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Solar Panel Maintenance and Cleaning – 2021

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Do dirt and other pollution affect the electricity production of solar systems? And if so, how much does it drop? Is cleaning really necessary? 

When is solar panel maintenance and  cleaning necessary?

Photovoltaic modules are attached to the outside of the house roof and can therefore get dirty quickly. But just because pollen, leaves, pine needles or bird droppings have collected on the system, this does not directly mean the need to clean a solar system. Light soiling is usually washed off the solar module with the next rain shower – without hiring a specialist company. In the case of particularly stubborn PV contamination, cleaning can be useful, but this seldom occurs and usually depends on the location of the solar system.

Less yield from the solar system due to pollution

Many private operators of solar systems are concerned with the question of whether a dirty solar module reduces the yield of the photovoltaic system. Basically, pollution is not a reason for a noticeable reduction in yield. In the event of a typical natural occurrence of dust or parts of plants that collect on the modules, a modern solar system continues to work constantly without any noticeable loss of performance. With the Maximum Power Point Tracker integrated into the inverter and, if necessary, module optimizers, the PV system can compensate for contamination in electricity production. The principle follows that of the (partial) shading of one or more solar modules. In addition, soiling of solar modules only lasts for a short time – the next rain shower will wash the glazed modules and remove soiling. Incidentally, this is also the effect of snow, which collects on the glass surface and slides off the solar modules together with deposits at warmer temperatures.

Do I have to clean my solar system?

Due to the natural removal of dirt on PV modules, cleaning of private solar systems is usually not necessary. The situation is different in rural areas. If your solar system is installed near a farm, more stubborn pollution can arise from the respective production facilities than in urban catchment areas. If you suffer from an increased amount of ammonia or emissions and dust from foundries or power plants, cleaning your solar system can be useful.

The angle of inclination at which the solar modules are attached to the house roof can also have an impact on the soiling of the solar system. Basically, an angle of inclination of the solar modules of less than 12 degrees is considered to be susceptible to deposits, since with a slight inclination rain showers or snow cannot wash dirt off the glass surface so easily. However, since most pitched roofs have an inclination angle greater than 12 degrees and elevated modules are installed at a suitable angle on flat roofs, this case rarely occurs.

Preventing pollution by maintaining the solar system?

The pollution of PV modules is one of the reasons for private photovoltaic system operators to carry out regular maintenance of the solar system. Many also expect maintenance to identify technical weaknesses or age-related wear and tear before they can have a negative impact on the performance of the PV system. When servicing a photovoltaic system, all components are first examined for wear or damage. At the same time, the degree of soiling is assessed and, if necessary, photovoltaic cleaning is carried out.

The technical components of a solar system are solar modules, inverters, solar cables and, in many cases, power storage devices for storing solar power. During the maintenance of the PV system, all components are checked for functionality, possible damage or a reduction in performance. Cables, for example, are examined for their insulation, as this ensures low-loss transport of solar power. The solar modules are also checked for technical performance and for possible disruptive factors such as dirt deposits. Contact points are secured, thus ensuring that the solar system will work properly in the long term. PV maintenance gives many solar system operators the security to be informed at regular intervals about the technical status and the performance of the photovoltaic system and thus to recognize possible defects quickly. In principle, regular maintenance is not necessary, as the built-in components meet a high technical standard and, with long guarantee periods, already provide a high level of security for the operator. With constant monitoring and the option of remote maintenance, deviations from normal operation can be quickly identified and corrected at the right place.

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When does it make sense to clean the solar system?

In the case of more stubborn deposits, you should first find out whether and to what extent the dirt affects the performance of your PV system. To do this, you create an invoice by means of which you can offset the loss of earnings due to a reduction in performance against the costs of cleaning. It makes sense to calculate the monthly yield of your own PV system based on your own consumption and the profits from the feed-in tariff. Compare periods of time when you think pollution may have reduced yields with your normal yields. When doing such a rough calculation, always take into account the weather conditions. Useful information such as the measured global radiation can provide information about

You should leave the cleaning of the solar system to professional cleaning companies. Even though the solar modules are glazed and many system operators often clean them like window panes, solar modules need special treatment. As a rule, PV modules are made of special glass which, due to its nature, must not be cleaned with conventional cleaning agents. In most cases, water is enough to remove dirt from the modules – soft cloths and not brushes should be used. The work of a professional cleaning company also eliminates the risk of falling while cleaning the roof. In addition, the manufacturer’s cleaning specifications may have to be observed. If solar modules are cleaned contrary to the recommendations for action,

In principle, offers should be obtained from possible cleaning companies and the estimated costs should be compared with the losses from the performance calculation of the solar system. Cleaning should only be considered if you find out that your system is actually showing losses in electricity production, also taking into account the irradiation conditions. For it to be worthwhile, the loss would have to be higher than the cost of cleaning.

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The maintenance or cleaning of the solar system are processes that usually only make sense under certain conditions. Through natural washing cycles, for example rain or snow, solar modules are freed of dirt and deposits and can work effectively without any reduction in performance. In some cases it may be necessary to clean the PV modules – for example in the immediate vicinity of agricultural operations, the emissions of which have an impact on the performance as deposits on the glass surface of the solar modules. Due to the nature of the glazing of modules, the cleaning of a solar system should only be carried out by professional companies. Damage to the solar modules caused by incorrect handling with cleaners or cleaning aids can have a negative effect on the manufacturer’s guarantee. Solar system operators who are interested in professional cleaning of the PV system should definitely compare the costs for the cleaning company with those of the actual financial losses due to the pollution, as performance reductions due to modern solar systems can usually be offset and no noticeable losses can occur. Regular maintenance of a solar system includes checking the deposits on the modules and checking the technical properties of the solar components. With a correct installation, manufacturer guarantees ensure a mostly smooth replacement of defective components, so that most maintenance is not necessarily necessary. In fact, once your solar system is installed on the roof of the house, it works

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