Solar panels are a growing method of producing clean and renewable energy in homes and businesses. However, a typical query that many individuals have prior to the installation of a solar system is whether or not solar panels require direct sunlight to operate.
The short answer is no-solar panels do not require direct sunlight to operate but they do operate best when they have access to direct sunlight. Solar panels are still able to generate electricity on cloudy days or in shaded areas but they do not do it as efficiently as when they are exposed to full and direct sunlight.
How Do Solar Panels Work?
To determine whether solar panels require direct sunlight, it is important to first learn how they work to produce electricity.
Solar panels are made up of photovoltaic (PV) cells. These are cells that trap sunlight, that is, photons of sunlight and convert it into electricity through a phenomenon known as the photovoltaic effect. When the sun beams touch the surface of the panels, they stimulate the electrons in the PV cells, and this results in the flow of electricity.
The greater the amount of sunlight the panels get, the more energy they can generate. That is why solar panels are usually mounted in places where they receive the most sunlight, e.g. rooftops or open fields.
Direct Sunlight vs. Indirect Sunlight
So, what is the difference between direct sunlight and indirect sunlight and how do they impact solar panel performance?
What Is Direct Sunlight?
Direct sunlight is the sunlight that has not been blocked or filtered. On a clear day, with the sun shining directly down on your solar panels, they are in direct sunlight. This is the optimum situation when solar energy can be produced because the panels are able to work to their full potential.
What Is Indirect Sunlight?
Indirect sunlight is sunlight that has been diffused by clouds, trees, buildings, or other obstructions. Even on an overcast or cloudy day, the rays of the sun do reach the ground, only not as strongly. Solar panels will still be able to capture this diffused light and convert it to electricity, but the amount of power generated will be reduced compared to that generated in full, direct sun.
Can Solar Panels Work Without Direct Sunlight?
The answer is yes; solar panels do not need direct sunlight to operate but their efficiency will decrease. Here are some of the common conditions in which this may occur and what to expect:
Cloudy Days
Solar panels continue to generate power even on cloudy days albeit at a lower rate. The percentage of your panels producing electricity may range between 10 and 60 percent, depending on how thick the cloud cover is. Although this is much less than when the sun is out, it is enough to keep your home partially powered, especially when you have a battery backup system.
Shaded Areas
Shade caused by other trees, buildings or chimneys can prevent the sunshine and decrease panel efficiency. The extent of performance loss will vary with the extent to which the panel is shaded and the duration during the day. Fortunately, most of the modern solar systems are designed to include such technologies as microinverters or power optimizers that reduce the effects of shading on the overall system performance.
Early Morning and Late Afternoon
The solar panels generate most energy when the sun is at its peak in the sky- usually between 10 a.m. and 4 p.m. Early morning or late afternoon sunlight is at an angle with the panels, and this causes a reduction in energy generation. Nevertheless, when these times occur, the panels still produce power but not at their peak.
How Location Affects Solar Panel Performance
The location where you are geographically is a major determinant of how effective your solar panels are. Regions that have more sunshine during the year will tend to generate more solar energy, e.g. the southwestern U.S. Nevertheless, in such states as Oregon or New York, where cloudy days are frequent, solar panels have the capability of saving a significant amount of energy in the long run.
The key is in the system design. A properly designed solar system will consider local weather patterns, roof orientation, and shading in order to maximise efficiency over the year.
What About During Winter?
The other worry that most people have is whether solar panels work during the winter. The short answer is yes–solar panels can work in cold weather. Actually, they tend to work more effectively in a lower temperature. In winter days are shorter and cloud cover more frequent, so energy production is usually lower than in summer.
When your solar panels are covered in snow, it can temporarily prevent sunlight. Fortunately, majority of the panels are installed on an angle, and thus the snow tends to slide off by itself. Solar panels are also made to be long lasting and can withstand cold and snow.
Maximizing Solar Panel Efficiency Without Direct Sunlight
Even when your home does not get full sun throughout the day, there are a couple of ways to improve the performance of your system:
Optimize Panel Placement
Install your solar panels so that they face the direction that receives the most sun, which is typically south-facing in the Northern Hemisphere. Avoid shaded areas that receive long hours of the day.
Trim Nearby Trees
Shade trees on your roof can significantly decrease the amount of solar exposure that your roof gets, so trimming or cutting down these trees can be a great investment. Always check with local regulations before removing trees.
Use Microinverters or Power Optimizers
Conventional solar systems have a central inverter that can lower production when only a single panel is in the shade. Microinverters or optimizers enable each panel to work individually, reducing losses in shaded areas.
Consider a Solar Battery
Having a solar battery installed would help you save the extra energy that is generated during the day and use it at a later time when there is little or no sunlight. This may be particularly useful on cloudy days or at night.
