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How do shadows affect solar panels? Are they really one of the biggest enemies of our photovoltaic panels?

Although it may not seem like it, shadows, whether total or partial, are one of the main enemies of solar panels . And this is because they will reduce the amount of electricity that the photovoltaic system can generate. In addition, over time they can generate hot spots and damage the cells of the solar panels. Therefore, they should be avoided at all costs.

However, there may be occasions in homes and buildings where shadows may be unavoidable given the location of the installation. And even then, the installation can be interesting, since there is photovoltaic technology that can reduce the impact of shadows.

This is why we at Cambio Energético strongly insist on the need to carry out a study prior to the installation of solar panels . For the case that concerns us, it is especially important to take into account the possible shadows when locating and placing the solar panels. And in case shadows are unavoidable, it is important to consider them when calculating the dimensions of the installation. Because if we don’t, it can affect the performance of the entire installation, in addition to slowing down amortization and not covering your consumption.

We say that the main effect is the reduction of the production of solar panels, but how much can it be reduced? Does the same thing happen in all types of photovoltaic installations? Is there a way to minimize the effect of shadows? In this article we will seek to clarify these issues, so that you can save as much as possible with clean energy.

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How much does shade affect solar panels?

The main effect of shadows on your solar panels is the reduction of photovoltaic production .

In the following monitoring of one of the photovoltaic installations that we have carried out, the reduction to which we refer is graphically observed.

Shadow monitoring example

In this case, the shadows coincide with the first and last hours of solar production. The production with the shadows ranges between 180 and 230 W and happens between 8 and 10 in the morning. This monitoring is carried out in the month of September 2020, a period in which at the indicated hours the photovoltaic production should be higher.

In this case, the percentage of production in the hours with shadows with respect to the maximum production of the day (4,079 W) ranges between 4.5% and 5.5%. 

Example of monitoring with maximum production point

Let’s take another example of monitoring another installation, also carried out in the month of September. As you can see, the production curve presents a greater regularity in the increase in production with the hours of the day.

Monitoring example without morning shadows

In this case, the production in the same hourly period is much higher, reaching 786 W. If we compare it with the moment of maximum production of the day (1,884 W), we have that in the same hours of the previous example, the production would be approximately 41.72%.

Therefore, if we compare both examples, we see that the effect of shadows can reduce performance by around 35%.

As we say, these calculations are approximate and based on real examples of installations carried out by Cambio Energético.

How do solar panels installed in string affect shadows?

With traditional chain or string systems, if one of the solar panels sees its production reduced, all the plates in the series will be affected. Thus, for example, if a panel is at 90% of its normal performance, the rest of the panels will equal the production of the solar panel with the least production.

String photovoltaic system

However, photovoltaic technology has been advancing to reduce the impact that shadows, cloudy days or dirt have on your photovoltaic modules. Let’s look at some examples of technologies that help minimize these impacts.

What are the Power Optimizers used for in cases of shade in our solar panels?

Power optimizers are a device that can help you minimize the impact of shadows on solar panels

The SolarEdge brand has specialized in the development of power optimizers. These are small devices that accompany each solar panel, so that they can be controlled and monitored independently.

System with SolarEdge power optimizers

Translated to the case of shadows, when a photovoltaic module with a power optimizer is affected in its performance, it will not revert to the rest of the panels . In other words, if one of the panels has less photovoltaic production, the rest will continue to work at maximum power.

How does a photovoltaic installation with Microinverters work against the shadows?

Brands such as Sunpower or SMA have opted for microinverters as a solution to the conditions that solar panels can have.

APSystem Microinverter

In the same way as the power optimizers, these microinverters are located in each panel, facilitating both individual control and monitoring.

Following the same logic, when one of the solar panels sees its performance reduced, the rest of the system will continue to work at maximum power.

Comparison of string system and Enphase microinverter

If you want to know more about this or if you should do an installation with microinverters or power optimizers, you can consult the article Differences between SolarEdge inverters and Microinverters .

Does the type or brand of solar panel used influence the shadows?

If your installation is affected by shadows and you do not have much space to install more solar panels, you can opt for higher quality solar panels . Although they are more expensive, they can assure you a greater production.

Opting for split cell solar panels is practically mandatory if we are going to have to deal with shadows. High-efficiency split-cell solar panels have the advantage that they respond better to shadows that may occur when they do not completely affect the panel but only part of it.

In addition to using higher quality and better efficiency solar panels, there are also other solutions on the market such as SunPower solar panels, which combine Enphase microinverter technology with Maxeon 5 solar panels with AC output as standard .

These panels are designed so that the entire front surface of the solar cells captures solar radiation. The efficiency of these modules is 22%, compared to 19% for conventional panels. In turn, although the useful life of solar panels is usually between 25 and 30 years, that of Maxeon 5 panels can reach 40 years.

In this article we have seen how careful we must be with shadows in our photovoltaic installation. We have also seen how we can reduce this impact thanks to technological advances. However, if you still have questions, contact us at Cambio Energético. We can advise you for free on which option is best for you to achieve greater savings with your photovoltaic self-consumption . We work with the best brands and we can offer you our services throughout the national territory. Ask us for a budget without commitment that we will gladly adapt to your needs. If you think of clean energy, think of Energy Change.

Summary: Frequently asked questions about how shades affect solar panels

How do shadows affect solar panels?

Shadows reduce the performance of your solar panels, that is, when your solar panels are affected by a shadow, they will reduce the amount of energy they are capable of producing.

How much is the performance of solar panels reduced by the effect of shadows?

Depending on the shade and the equipment you have (plates, inverters, optimizers, etc…) the energy produced by your shaded solar panels can be reduced by around 35%.

How can the effect of shadows on solar panels be reduced?

Advances in photovoltaic technology make it possible to reduce the impact of shadows on our photovoltaic production. The use of split cell solar panels, power optimizers or installations with microinverters that work at the panel level can help us reduce the impact of shading on solar panels. This is because if a shadow affects a solar panel it will only affect this panel and not the entire string. There are also high-quality solar panels that reduce the impact of shadows.

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