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Shadows on solar panels and optimizers

Shadows on solar panels may be unavoidable at some times of the day and in certain installations. However, with proper installation it is possible to minimize this inconvenience without affecting energy production.

How do shadows affect solar panels?

Solar panels are installed to obtain electricity from sunlight and therefore the energy production depends directly on the amount of sunlight that the installation receives. The shadow of a tree, a pipe, a billboard or any other object that stands between the sun and the photovoltaic cells can considerably reduce power generation. This is something that must be taken into account when carrying out the preliminary study of the installation to prevent shading from reducing the efficiency of the system, and that malfunctions can damage any of the module’s components.

A small shadow at a certain point in the photovoltaic system can greatly reduce the production of the entire system. In addition, when one of the cells of the solar panel is shaded, its resistance increases and causes it to overheat. This can create a hot spot over time and cause the cell to rupture. There are several solutions to minimize the inconvenience of shadows on solar panels .

Impact of shading on series and parallel connection

According to some calculations made by experts in solar energy , the shade on one of the cells of a small and standard photovoltaic module of 36 cells, can reduce production by more than 75% , so one of the main problems caused by shading is the reduction of the efficiency in the operation of the installation . Solar panels combine a certain number of photovoltaic cells that can be connected together in series or in parallel . The impact is different in one system and another. In a series connection, power losses can reach 50%. In the case of a panel with a parallel connection, the losses are higher, reaching up to 90%.

Example of installation of solar panels on a façade with shadow effects

In the following image we can clearly see how there are several shadows that affect the solar panels installed on the facade of this building. To solve it, it is essential to install optimizers. Tree branches and urban lighting furniture cast shadows on the solar panels.

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Shading Types

Shadows on solar panels can be of two main types: vertical and horizontal . A shadow that measures approximately 1 meter can reduce the operation of up to 6 meters of photovoltaic installation. This means that the study of possible shadows is one of the most important steps during the initial analysis and design of the solar panel installation. Therefore, it is essential to carry out a field study to evaluate potential and eventual obstacles, at the present time and in the future, that could cause a blockage of light and affect the performance of the system. Solar energy experts resort to certain mathematical formulas that allow them to accurately calculate the solar shadow, and thus be able to propose the most suitable system to the client and provide realistic expectations of the amount of energy that the installation will be able to supply.

How to avoid shadows on solar panels?

To solve the problem of shadows on solar panels there are two factors that must be taken into account. The first is the calculation of shadows , essential especially if it is a large installation or a module with several panels connected in parallel or in series. With these data, an installation with solar panels placed at the most appropriate minimum distance can be designed. In this way we will avoid producing shadows between each other and avoid possible shadows from other objects.

The second point is to know the inclination that the solar panels should have at the solstices, also taking into account the country and the region. In Spain , the ideal inclination is between 20º and 40º, depending on the latitude. The smaller the distance to the equator, the smaller the angle of inclination, as the rays strike the plates more perpendicularly. In the south of the peninsula, for example, the inclination is 20º-25º, and in the north, it should be around 40º. The inclination and the distance between the panels of the installation are two important keys to avoid shadows.

What are shadow optimizers

The shadow or power optimizer is a component that is part of the photovoltaic installation that is used to reduce possible losses that may occur in the panels due to shadows generated by obstacles, and even by dirt. It helps to maximize the efficiency of the module as a whole.

The optimizer, unlike the inverter, has to be placed in each panel. This way you can work individually and optimize the maximum power point separately. It does not transform the energy, but rather maximizes the direct current before redirecting it to the inverter.

Check the roof and roof orientation before installing solar panels

Another aspect that must be studied to avoid shadows on solar panels is orientation. The ideal is the south orientation or azimuthal angle of 180º , since in this way the installation can receive the maximum solar irradiation during all possible hours of the day, and the performance of the installation will be optimal. If the roof is not correctly oriented or shadows are produced, it is advisable to assess other surfaces on which to carry out the project. It can be on the ground, above the garage, or even on the wall, on one of the facades of the house or building. Analyzing different options you can find the best solution to enjoy solar self-consumptionand a solar installation that can provide the best performance.

Free study for the installation of solar panels with EFC SOLAR

If you have a well-oriented space without shadows, you are in luck. With solar panels adapted to your needs and a quality inverter , you can enjoy a good electricity supply. This will cover a good part of your energy demand. If you have it a little more complicated and your roof is not well located or has obstacles that generate certain shadows, it is advisable to bet on a system of optimizers with which you can take full advantage of the installation.


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