Rainy Days & Solar Panel Efficiency: Expected Energy Performance

February 12, 2021
By John Cole

Sharing is caring!

When we think of solar panels, we think of energy from the sun. When we consider weather patterns, we become aware that sun is not a guarantee. The question is then raised, what happens to efficiency of  solar panels in the rain?

To make an investment in solar panels, we want to know that they are going to provide the energy we need. To put the effort into converting to a new resource for the production of energy, we have to consider many factors. We have to consider what is known about them, what benefits are available, what limitations exist, as well as what is uncertain or risky. Fortunately, in the world of solar panels, research is being conducted to determine which products can withstand weather and elements, and continue to perform. In addition to the performance of research, there are options available that help refine continuous improvements. 

How Much Less Sun Do Rainy Days Provide?

Cloudy days and rainy days provide less sunlight overall, which reduces the resource of sun available for the solar panel to function. On rainy days there is up to 90 percent less sunlight, which is a significant decrease in resources. Even when we do not see direct sunlight, there is still some sun available for absorption. Does 90 percent less sunlight directly translate to 90 percent less effectiveness?

Some additional considerations are to look at the molecules used in solar energy panels, how they work,  how they respond to sunlight over time, and how much sun is required to achieve energy production from a solar panel. Having significantly less light available does raise some concerns on how the solar panel can remain effective. Less sun does indicate limitation, which is what is frequently explored in research to create low-cost, high-efficiency solar panels that maintain the output of energy in all conditions. 

Materials Used in Solar Panels & the Relationship to Weather Conditions 

close up of solar panels on a home roof

In the last few years, it has been determined and proven that perovskite materials are more effective while meeting low-cost goals. Perovskites are a class of materials that have superconductivity properties and display a similar structure. Perovskites have additional properties, and further research looks to make these materials more stable. The structure of perovskites is a crystal.

Developments in Solar Materials Used

The most recent materials for perovskite solar cells studied are methylammonium lead halide. This has been an upgrade from materials previously used in multiple realms. This material has increased efficiency and has eliminated the instability factor of a corrosive liquid layer. This progress in itself has made great strides and improvement, though it should be noted that even further improvements to stability and efficiency are being explored.

solar materials used

The lead absorption layer increased sunlight to energy conversion significantly, and now silicon is being explored to increase conductivity. An overall increase in efficiency means greater output on even the days with the worst weather conditions! Increased conductivity increases the efficiency of the solar panels.

Reactions within the materials are mobile due to the separation of bromine and iodine that takes place during illumination. The specific material combinations, the shape of the molecules, and the reactions that take place all coordinate together to receive and absorb sunlight that is transferred into produced energy. There is also a variety of materials and combinations in this material class that can be tested for improved outcomes. 

Additional Research Trends in Performance of Solar Panels

With a known issue of limited resources however, trends in research are looking at materials that help absorb blue light and reflective light to increase the ability of solar panels to produce energy. The goal of current research is to design a solar panel that can operate more efficiently, and also withstand the weather conditions while also serving to be low cost.

Research requires consideration of thermomechanical properties and chemical instabilities.  Thermomechanical properties are what explain the process of the cell in the solar panel absorbing the sunlight, and converting that light to energy that can be utilized. The chemical instabilities relate to chemical reactions to molecules in the air, and in rainwater.

rain water on the ground impacts solar panels

Advancing the Research on Tandem Cells

In addition to achieving effective, low-cost molecule options, research is looking to apply tandem cells to solar panels. Tandem cells allow the solar cells to absorb and harvest photon energy, or light. This absorption allows the resources for conversion to be on hand to continue conversion to energy when the direct light resource may be limited. 

Finding Materials That Are Stable & Affordable!

In addition to finding a material that allows an attractive cost, an efficient conversion of light to energy, research is also looking at how to create a stable material that can also be mobile enough to perform the conversion desired from an energy panel.

For some protection from elements, additional research sources are looking at a spray coating on the panels, that allows the molecules inside to react to light, but not react to weather circumstances. Stanford University engineering uses a rapid spray plasma processing layer to make the panels more resistant to outside elements, while still being efficient.

Potential Elimination of Lead Use with Solar Panels

Furthermore, there are concerns with solar panels that are also being researched. These concerns are not limited to the encapsulation of perovskite solar cells to protect them from the environment, and help predict how long the panels will last, and eliminating the use of lead in the perovskite materials to reduce lead toxicity. Encapsulation provides an outer barrier to the perovskite, or solar cell that also allows light to come through. While lead proves to be a superconductor, there are concerns about it being used as a prevalent material because of its nature to be toxic and harmful to health in large quantities.

With support from the Washington Clean Energy Testbeds, there is also work with a high-resolution printer to print electrodes in screens, so energy can be pulled out of solar cells without any sunlight being blocked. There are a variety of research topics to address multiple goals. Overall goals consistently include improving the efficiency of solar panels, maintaining a low cost, and keeping the materials safe with advanced technology. 

Do Solar Panels Work When it's Raining?

So, it is cloudy on rainy days, but does the rain have any additional impact on solar panels? The water itself can interact with the perovskite materials, and change the conversion of energy or prevent it.

Research in regards to film and encapsulation are working to prevent the rain from causing interactions, and increase efficiency through all weather. This will also help to improve the stability of solar panels, by allowing a more consistent efficiency.

In addition to affecting the conversion, the rainwater can cause additional interactions. This additional interaction can cause lead to be removed from the perovskite, and be released into the environment. Rainwater contains additional chemicals that could cause more of a reaction than water alone. This reaction utilizes energy differently and can prevent the reaction from producing energy for use.

In the research, circumstances that represented the worst-case scenario were the circumstances utilized to evaluate environmental concerns, and these concerns were fairly low at those levels, let alone in real-time situations. While there is potential for additional concerns on rainy days, the largest limitation remains the simple lack of sunlight on rainy days. 

How Can Materials Be Improved to Overcome These Limitations?

solar panels on a sunny day

With a variety of materials available for use, there are options to explore the most effective combination for energy conversion. There are also a lot of approaches to improved protection, and improved options in supplementing energy when resources are limited. A lot of the current research is looking to overcome these limitations by creating a more stable product. Factors that involve encapsulation or changes to film material seek to protect perovskite cells without creating a barrier for the sunlight to be absorbed.

Further refinement  of materials keeps the solar panels low cost, safe for the environment while simultaneously improving the efficiency. For solar panels to be utilized as an energy source, they also need to work all the time, and not just in ideal conditions. For that purpose, there are continuous advancements and production of hybrid solar panels that work in sun and rain. These hybrid solar panels convert energy from the sun and energy from the force of rain hitting the film. 

a rainy day impacting solar panel efficiency

Instead of allowing the rain to be a limitation, finding a way to utilize it for conversion output advances the potential for solar energy to be a productive source of energy. The force is utilized through triboelectric nanogenerators which transform rain into energy when the sun isn’t as bright for a supplement source of energy. This helps more people utilize solar panels for energy regardless of the environment and conditions. While the science isn’t entirely new, a lot of factors relating to solar panels continue to be researched and improved for a more effective green approach to creating usable energy. 


Overall, solar panels have made great progress in recent years. Moreover, solar panels have also made improvements in working under a variety of circumstances and conditions, which reduces some of the limitations of their function overall. As research is performed and refinements are made, the effectiveness improves a little bit at a time. The functional measurements still provide some limitations to solar panels as a sole energy source, though they can still be a productive supplement. Research provides upward trends in materials used targeting solar efficiency during less than ideal weather condtions, though it appears there is plenty more to continue to learn and explore.

For more information about your home solar panels, get in touch with Green Energy Geeks to learn about the benefits of solar panel installation today!

Leave a Reply

Your email address will not be published. Required fields are marked *

Copyright © 2024 Green Energy Geeks. All Rights Reserved.
Green Energy Geeks