I argued with my friend about this subject. His answer to the question, “do solar panels need direct sunlight to produce energy?” was a resounding yes! Like most people, he thought solar panels tap into the heat from the sun to produce electricity.
This article will give you valuable insight if you think like that. But before we dive into the gist of this discussion, let’s set the record straight.
Solar panels do not need heat from the sun to produce electricity; rather, it converts the sun’s rays or light that falls on its photovoltaic cells into solar energy.
Now, let’s answer some questions that will help us answer the main question- how long can solar panels last without the sun?
If you wonder How Much Energy Solar Panels Generate in Winter, please read this article.
Do Solar Panels Need Direct Sunlight?
Solar panels can work without direct sunlight to generate power. Since photovoltaic cells in solar panels absorb sunlight, not heat, they can function even when direct sunlight is blocked.
In fact, my discussion with my friend pushed me to research this subject further, and I unearth interesting stuff that I will share throughout this article.
But what about when there are clouds? Do solar panels work on cloudy days? The answer is yes. The sun does not disappear on cloudy days. You will still see the light even when it is about to rain, and that light is what solar panels need to generate electricity.
The panels can utilize “diffuse light”- light that reflects the earth after hitting particles like clouds in the atmosphere. This light may not be intense as direct light, but solar panels utilize it to produce power.
The free electrons on the solar panel’s cells move when hit by sunlight (directly or indirectly). And when they move, they create current that generates electricity.
Do Solar Panels Work At Night?
Solar panels need sunlight to produce electric power for your home. At night, there is no sunlight because the sun has set. Therefore, solar panels cannot generate electricity at night.
This is an interesting question, but the answer is apparent based on what we have discussed thus far.
But, then, can solar panels benefit you at night? You can invest in solar power backup batteries. Your solar panel system will absorb sunlight (Direct current) during the day and convert it into alternating current (AC), which you use in your home.
If you wonder how to choose batteries for solar panels, I wrote a whole article that I encourage you to read.
However, when sunlight is intense, the solar panels produce excess power than needed. Where does the extra power go? If you don’t tap it and store it, it is lost.
So, what solar power backup options do you have?
1- Solar Power Batteries
You can take advantage of excess solar power and store it in solar battery power banks. Check out a list of the best solar battery storage you can buy.
These batteries store solar power you can use during the night when the sun goes down.
During the day, when no one uses power from your panels, they generate power, and the batteries stores it. At night, you light your home through stored energy. Your electricity bill has no choice but to shrink.
2- Net Metering
Net metering is another way you back up the excess electricity generated from your solar panel system. What is net metering?
Net metering is where you install home solar panel systems while still connected to the grid. But when you produce excess electricity from the solar panels, you channel it back to the grid instead of storing it (Source: Solar Energy Industries Association)
You become an electric power produced. The utility company takes note of your contribution and compensates you monetarily or through a reduced electricity bill.
Net metering is like lending credit to the utility company or saving your power with them during the day and utilizing it at night when your panels are not generating energy.
This idea ensures your home remains connected to the grid. This means you will still have power even if circumstances do not permit your solar system to produce maximum electricity.
Do Solar Panels Work Without The Sun?
Solar panels may not need direct sunlight to generate electricity, but saying they can work without the sun, is an exaggeration. Solar panels without backup storage batteries do not store the energy you can draw from when the sun has risen.
The panels need the sun (even if it is invisible). Without the sun, what do on the sky, what will we have?
Darkness. And solar panels cannot work in darkness.
Can Cold Weather Affect Solar Panel Efficiency?
The truth is that solar panel work more efficiently in cold temperatures than hot ones. In fact, during extremely hot temperatures, the performance of solar panels drops by around 10-25%. The panels are like any other electronic gadget affected by heat.
If the heat goes beyond 25°C, solar panels degrade. However, at cold temperatures, the electrons are closer to the protons, thus generating a huge power difference.
I know many people ask this question because major solar power plants are located in deserts.
The fact is that solar panels work perfectly well in cooler temperatures. You rather have shorter periods of intense sunlight in cool weather than long hours of extreme heat.
Technological Innovations That Make Solar Cells Work Without Sunshine
Technology has propelled many industries, and the solar industry has benefited from various innovations.
Here are some brilliant innovations that improve solar panels’ efficiency when the sun is not bright.
1- Using Bacteria To Convert Sunlight Into Energy
The future looks brighter for the solar energy industry as scientists turn to biophotovoltaics to generate electricity.
This process uses bacteria (cyanobacteria) responsible for photosynthesis to generate an electric current from sunlight.
Researchers from the University of British Columbia in Canada found that cyanobacteria can split water molecules into hydrogen ions, oxygen, and an electron.
Photosynthetic microorganisms can be used to convert sunlight into biophotovoltaics. Scientists hope to make biological solar panels with these bacteria or embodied E. coli.
This is a promising application that could enhance solar harvesting in cloudy conditions. Furthermore, the bacteria release huge amounts of lycopene with great potential of generating more electricity from heat.
Biological solar panels would generate electricity even in the depth of the sea and mines. We hope that it will become a reality soon.
2- Generating Electricity From Raindrops
When it is raining, the sun is likely not shining. But can raindrops coupled with solar panels provide electricity?
Chinese scientists developed thin graphene layers and applied them on solar panels to generate power when raindrops hit them.
But how? Rainwater has elements of salt, including calcium, sodium, and ammonium. And when raindrops fall on the panels, they split into ions. Ions, water, and graphene are a perfect combo for generating electricity.
Another way raindrops generate electricity is through piezoelectric materials. When the rain hits the surface of these materials, it creates kinetic energy, which is converted into electrical energy.
Do Solar Panels Produce Electricity In Winter Or Snowy Days?
Rain, clouds, and snow often characterize winter times. The sun could shine for a few hours, thus limiting the amount of energy you can generate by solar. Your solar system will still produce electricity because the sun provides light from the sky, although covered by clouds.
What about snow? Most solar panels are installed on a slanting slope without frames to prevent snow accumulation. But if some snow still covers part of your solar panels, you can remove them to allow the light to reach them.
You should expect to generate less energy during winter because the sun is up in the sky for a short period.
Are Solar Panels Efficient Without The Sun?
We have established that solar panel systems do not need direct sunlight to produce electricity. However, direct sunlight matters because it affects the efficiency of photovoltaic cells.
So, solar panels’ efficiency will drastically drop without direct sunlight. One more thing to remember is that your solar panels’ efficiency also depends on their power output and size.
Smaller panels will take more time to generate solar energy than their larger counterparts. So, when installing solar panels, choose larger units.
The type of solar panels also determines their efficiency. For instance, polycrystalline and monocrystalline differ in efficiency, with the former working efficiently in various weather conditions.
Monocrystalline solar panels can generate more energy from minimal spaces. They also have a longer life expectancy but perform poorly in shady and cloudy conditions.
You can learn the difference between monocrystalline and polycrystalline from our recent blog.
What to read next:
- Difference Between Single Axis And Dual Axis Solar Trackers Explained.
- Are Solar Panel Trackers Worth It? (Including their pros and cons)
- Different Types of Solar Tracking Systems and how they work?
How long will solar panels last without the sun? Solar relies on sunlight to generate electricity. Solar panels cannot generate electricity when the sun goes down and darkness sets in.
However, if you have solar storage battery backups, you can continue to light your home as long as the batteries still have power. They can take you for a whole night, depending on the number and types of batteries you have.