How Solar Energy Works: The Basics

What Is Solar Energy?

Solar energy is radiant energy, or heat, from the Sun directly applied to human needs. The energy level of the sun can vary based on the time of day and year, but as long as there is sunshine, there is always the possibility of producing energy.

In summer, the Sun is at its peak and can produce a lot of energy, which means that it is hot enough to run most heat-related appliances and drive most forms of transport. Conversely, in winter, when the Sun is at its lowest point and gives off the least amount of energy, it can be a struggle to heat homes and businesses, especially in Northern and Southern countries alike.

Where Does The Energy Come From?

The Sun provides energy to the Earth in the form of light and heat. When light is composed of a large number of photons, it can become energetic enough to break chemical bonds, or in other words, to ionize certain molecules. When this happens, the photons lose some of their energy and are no longer able to ionize other molecules. This is called photoelectricity and is what allows for energy conversion via solar cells.

The Sun is a natural source of energy, but human activities such as manufacturing, driving, and heating have put a lot of pressure on the Earth’s atmosphere and oceans. As a result, the climate is changing, and the effects are being felt in all parts of the world. In order to combat climate change, we must look to renewable energy sources such as solar energy.

How Does Solar Energy Work?

When the Sun shines on a solar cell, it produces an electric current.

This may be as simple as a direct connection between the two, but in reality, it is a bit more complicated. The amount of energy produced by a solar cell depends on a number of factors, the most significant of which is the size of the cell. The larger the solar cell, the more energy it will produce. The cell’s efficiency decreases as the temperature increases, so it is best to keep the temperature as stable as possible. This can be achieved by covering the cell in a greenhouse or enclosing it in an airtight container.

What Are Solar Cells Made Of?

A solar cell is made up of three layers: a p-n junction, the contact layer, and the emitter layer. The p-n junction is the layer of atoms that separates an n-type material from a p-type material. Most often, the p-type material is silicon and the n-type material is copper or aluminum.

The contact layer is the layer where electric contacts are made to the device to allow for an electric current to flow. The charge carriers (i.e., electrons and holes) move across the p-n junction to this layer, where they are collected and deposited on the surface through a series of electric contacts. The final layer is the emitter layer, where light-induced electron-hole pair (e.g., photoelectricity) are produced and collected to generate electricity.

How Do Solar Cells Work?

When light interacts with a solar cell, the photons of light are absorbed by the cell, causing the electrons in the cell to migrate to the point of impact, or in other words, to the atoms that produce the p-n junction. This effect is the photoelectric effect, and it is what allows for the production of electricity via solar cells. When light is absorbed, it gives off a certain amount of energy that is directly proportional to the frequency of light absorbed. Light with a higher frequency gives off more energy than light with a lower frequency, all other factors being equal. This ability to convert energy from one form to another is what makes solar cells so versatile and so valuable.

Although the photoelectric effect was first observed and studied over one hundred years ago, it was not until 1931 that Dr. Albert Einstein coined the term “photoelectricity”. In that year alone, he published three papers on the subject, each with stunningly brilliant conceptualizations and mathematical formulas that still hold true today. One of these papers, “Solar Energy”, described how sunlight can be converted to electrical energy via a solar cell. In essence, the power of the photoelectric effect leads to the production of electricity without the need for any other energy source. This is why solar cells are often called “sunlight concentrators” or “photovoltaic cells”.

Where Can I Buy Solar Cells?

You can purchase solar cells in large retail stores or small, independent solar cell producers. Large retail stores that stock a variety of electronic products also tend to have some solar cells on offer, while independent solar cell producers sell directly to electronics companies, aircraft manufacturers, and scientific research facilities.

What Are The Different Forms Of Solar Cells?

There are many different types of solar cells, but they all operate using the same basic principles. The light-dependent conductivity of the cell allows for the transport of electricity, and with it, the ability to power electronic appliances and vehicles. This property makes silicon-based solar cells ideal for this purpose, and over the years, a number of silicon-based solar cell varieties have been developed with the sole purpose of powering various technologies. 

Nowadays, it is possible to find all kinds of solar cell products, from small, lightweight cells used in calculators and laptops to medium-sized solar cells suitable for use in satellites and space stations. However, even the largest and most powerful cells can be damaged by exposure to high temperatures, making them unusable above a certain threshold. It is also vital to keep an eye on the Sun’s intensity as the seasons change, particularly in the northern and southern hemispheres, where the intensity fluctuates greatly and regularly, making it more difficult to predict how much energy a solar cell will produce. As a result of all this, the best way to ensure you always have a steady supply of electricity is to use storage devices such as batteries or superchargers.

How Many Watts Can A Solar Cell Output?

The power of any wattage is defined by the formula: 

$$ P = I^2R $$

Where P is the power in watts, I is the current in amps, and R is the resistance in ohms. The power of a solar cell is measured in watts and expressed in terms of the current (amps) that flows through it and the resistance (ohms) that occurs at that current. The formula for the power of a solar cell is simple enough, yet it takes into account all the factors that can affect a cell’s efficiency, namely the current, the voltage, and the resistance. If we rearrange the equation a bit, we get:

$$ P = IR^2 $$

Where R is the resistance (ohm) and I is the current (amp) flowing through the device. This equation shows that the power of a solar cell is directly proportional to the square of the current (I²R²). As we already established, sunlight contains a large amount of energy, which directly translates to a high current. This leads to a solar cell’s wattage being expressed in the form of I²R², where I represents the current in amps and R represents the resistance in ohms.

What Is The Voltage Of A Solar Cell?

The voltage of a solar cell is the difference between the maximum voltage and the minimum voltage that can be produced by the device. The formula for the voltage of a solar cell is: 

$$ V = IR $$

Where V is the voltage (volts) of the device and I is the current (amps) flowing through it. Once again, as we established earlier, the power of a solar cell is directly proportional to I²R²; this can also be expressed as V=IR. In this instance, R represents the resistance of the device (in ohms) and I represents the current (amp) flowing through it. When we put these two formulas together, we get:

$$ V=IR^2 $$

Which again, shows that the voltage of a solar cell is directly proportional to the square of the current. As we established earlier, solar cells produce a high current, and with it, a high voltage. The difference between the high voltage and the low voltage (directly proportional to the intensity of the Sun) in a solar cell makes it possible to store electricity in the form of electrical charge. The ability of a solar cell to store electrical charge is known as its capacitance (uF).

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