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How Do Solar Panels Work? (Everything You Need To Know)


Solar panels are actually made up of groups of photovoltaic (PV) cells that take energy from the Sun to produce electricity. These PV or photovoltaic cells convert sunlight into electricity by establishing an electric field between a positive charge on one side and a negative charge on the other.

PV cells are arranged together in groups to form PV panels that can generate electricity to power everything from handheld devices to entire communities. These solar panels can also be arranged together to form a solar array. The more panels you use, the more energy you can generate.

Recent advances in the technology of solar cells include the creation of cells that are just 1.3 microns thick and so light that they can sit on top of a soap bubble, yet are still able to produce as much energy as more traditional glass-based cells. These lighter cells open up more applications for solar power.

Each solar cell is made up of two slices of semi-conducting material (often silicon) which has been ‘doped’ with other materials to give each slice either a positive or a negative charge. The top slice is usually seeded with phosphorous to add electrons and create a negative charge, while the bottom slice has boron added, resulting in fewer electrons and a positive charge. Each layer includes metal conductive plates on one side, and the junction between these layers is where the electric field is created.

When a photon of sunlight strikes the cell it knocks electrons loose from their atoms. These freed electrons are then able to flow between the conductors and through the circuit to generate electricity.  This direct current electricity flows in one direction through the circuit, from the negative to the positive side. However, the current needs to be passed through an inverter to convert it into an alternating current (AC) electricity, which can then go to the Grid, be used in home solar systems or to power businesses. AC power pushes and pulls the electrons, periodically reversing the direction of the flow. This type of current is created with an inverter, which also provides system statistics and ground fault protection. Micro-inverters that optimise each solar panel in a system can improve the output of the entire system as a problematic panel (such as one that is dirty or in the shade) will not drag down the performance of the entire solar array.

The Sun is one of the world’s greatest natural energy sources, with enough potential energy reaching the Earth each hour to easily meet the global energy needs. In addition, solar power is a fully sustainable and renewable energy resource, which doesn’t release harmful greenhouse gases into the atmosphere.


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TWI provides our Industrial Members with support for a range of services related to renewable energy sources, including solar power. Among the projects we have worked on are the development of a coating to improve the performance of solar cells and defect detection methods for solar panels. In addition, we can provide solar reflectometry services, measuring solar reflectance and absorbance on surfaces to help mitigate climate change.

TWI is an Industrial Membership based organisation who can provide your company with an extension to your own resources. Our experts are dedicated to helping industry improve safety, quality, efficiency and profitability through all aspects of materials, joining, and allied technologies. Industrial Membership of TWI currently extends to over 600 companies worldwide, embracing all industrial sectors.

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Solar Panel Efficiencies

Solar technology is more efficient than many people believe. Solar cells don’t need bright sunshine to work and can produce electricity even on a cloudy day. Of course, they are most efficient in bright sunlight and there are also a number of steps you can take to improve the efficiency of solar panel electricity generation.

Different sizes, thicknesses and purities of PV cells will produce varying amounts of energy, with the purer types producing more electricity but also being more expensive. You should also orientate your solar panels to catch as much solar energy as possible. In the Northern Hemisphere, this means facing the panels towards the south, while the inverse is true in the Southern Hemisphere. The angle of the panels will also impact their efficiency as the seasons change and will depend on where in the world you are based. For example, solar panels on a roof in London, England are best placed at a 51-degree angle while, about 550 miles away, in Aberdeen, Scotland they are more efficient at a 57-degree angle.

It is also worth considering sources of shade, including trees, and remember that the amount of shade can change through the year if, for example, you have deciduous trees that shed their leaves.

Finally, the more panels you have and the larger they are, the more energy you will be able to produce. You can reduce the amount of space required by increasing the purity of the solar cells you use, but this will also have cost implications.

A Solar Panel for Use at Night?

Solar panels work by harnessing the energy of sunlight to create energy, but what if we could also use the technology to generate power when it is dark?

Research carried out at the University of California has led to the design of a night solar panel (NSP) that is able to produce 50w of power per square metre when used under the ideal conditions at night. This is around a quarter of the energy that can be generated using traditional solar panels, although it is hoped that further research will improve the power output and efficiency of these panels.

Where normal photovoltaic cells work by absorbing sunlight an NSP uses thermoradiative cells, which radiate heat as infrared light. Because outer space is incredibly cold, if you take a warm object and point it at the sky, it will radiate heat and infrared light upwards. This effect allows the thermoradiative cells to generate electricity using similar physics principles as those used by photovoltaic cells. Where regular solar cells absorb light to cause a voltage to appear and the electric current to flow, a thermoradiative cell works in reverse, emitting light and making the voltage and current flow in the opposite direction.

While improvements are needed for these cells to reach the efficiencies seen in traditional solar cells, researchers believe that these NSPs could provide 24-hour energy if they are shaded or pointed away from the Sun during the day.


How do Solar Panels Work on a House?

Solar panels work by absorbing sunlight and converting it into direct current (DC) electricity. This DC electricity is then converted into alternating current (AC) electricity using an inverter, as AC electricity is the type used by most electronic devices and appliances.  This electricity is now ready to be used or stored at the grid.

How do Solar Panels Work at Night?

Strictly-speaking, solar panels do not work at night. This is because they rely on sunlight as the source of their energy and there just isn’t enough around at night-time to produce electricity. However, energy generated by photovoltaic cells can be stored and used later.

Despite this, there are investigations underway into a new type of panel, known as a night solar panel (NSP), which can generate electricity at night using thermoradiative rather than photovoltaic cells. You can find out more about these above.

At What Temperature do Solar Panels Work Best?

Most solar panels are rated to reach peak efficiency at temperatures of between 59 and 95°F. They are tested at 77°F, but can reach temperatures of around 150°F. When the panels reach these higher temperatures they lose efficiency, so heat is not always good for solar panels.

What Hours do Solar Panels Work?

Solar panels are at their most efficient when the Sun is at its highest in the sky and when the weather is clear and sunny. This means that, for most places, they are at their most efficient around noon. However, the exact hours when solar panels will work depends on where you live and what time of year it is as, the longer the daylight lasts, the more hours can be spent generating power.

Where do Solar Panels Work Best?

Solar panels are at their best in places that receive lots of strong sunlight and work most efficiently when the Sun is at its highest during the summer months. They produce less power when the Sun is still rising or going down or during the winter. The direction the panels face also has an impact on productivity, depending on whether you are north or south of the equator.

Do Solar Panels Work Forever?

Most common solar panels last for between 25 and 30 years, offering decades of use. However, technological advances, self-cleaning coatings, and other innovations could see the effective life of solar panels increase further.

How do Solar Panels Work When It Snows?

A thick layer of snow will block the sunlight from reaching the PV cells and prevent them from working until it is removed (or eventually melts). However, a small amount of snow should melt away or blow away, meaning that solar panels can still be used in snowy environments.

How do Solar Panels Work When It's Cloudy or Raining?

Because solar panels work on the visible light spectrum, they only need the same amount of light as you take to see. This means that they can still operate on cloudy days, although the stronger the sunlight, the more power solar panels will generate. It is the same when it comes to rainy conditions although the amount of power generated is lower still.

Average figures for solar panel power generation during monsoons show that solar panels generate 30-50% of their optimum generation on cloudy days and 10-20% in heavy rain.

When do Solar Panels Start Working?

Solar technology starts working as soon as there is enough light to convert into energy. This is generally the same as the amount required to see, although the stronger the sunlight, the more energy solar panels will produce.

When do Solar Panels Stop Working?

Solar panels can stop working for a range of different reasons – when it gets dark being the most common, as they generally require sunlight to work. However, they can also stop working if they get too hot, if they are covered (by thick snow, for example), if they get dirty or simply as a result of components breaking down or getting damaged.

When do Solar Panels Not Work?

Solar panels will work throughout the year to generate electricity in all seasons, provided their isn’t a fault, they aren’t damaged and the conditions are right. However, they will produce less energy in lower light or in winter when the days are shorter.


Most solar panels are made from photovoltaic cells grouped together to convert sunlight into electricity by creating an electric field between a positive and a negative charge. Panels can be arranged together into larger solar arrays to increase the amount of energy being delivered.

There are a number of factors that impact the efficiency of solar panels, such as cleanliness, light levels and heat. However, once installed, solar panels provide emission-free, renewable energy using just the natural power of the Sun.

Solar energy provided by solar panels, either on a domestic or an industrial level will play a part in a wider renewable energy mix as nations move away from the use of fossil fuels.

Related Frequently Asked Questions (FAQs)

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