How Does Solar Panel Work? (Power Generation Principle)

Solar power is a renewable and infinite energy source that creates no harmful greenhouse gas emissions. Not only is solar power good for the environment, but you can earn money selling back excess power to the grid. Solar panels work by harvesting the sun's energy and converting it into electricity. In this article, we will learn how solar panels work, how they are made, and how they generate electricity.

What Are Solar Panels?

Solar panels are those devices which are used to absorb the sun's rays and convert them into electricity or heat. Solar panels are usually made of solar cells (made from the element silicon), wiring, a metal frame, and a glass cover. Lots of small solar cells spread over a large area can work together to provide enough power to be useful. A typical solar panel is about four feet wide, and six feet tall.

In addition to residential and commercial use, there is large-scale industrial or utility use of solar. In this case, thousands or even millions of solar panels are arranged into a vast solar array, or solar farm, which provides electricity to large urban populations.

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Additional Important Parts to Solar Panels

Aside from their silicon solar cells, a typical solar module includes a glass casing that offers durability and protection for the silicon PV cells. Under the glass exterior, the panel has a layer for insulation and a protective back sheet, which protects against heat dissipation and humidity inside the panel. The insulation is important because increases in temperature will lead to a decrease in efficiency, resulting in a lower solar panel performance.

Solar panels have an anti-reflective coating that increases sunlight absorption and allows the silicon cells to receive maximum sunlight exposure. Silicon solar cells are generally manufactured in two cell formations: monocrystalline or polycrystalline. Monocrystalline cells are made up of a single silicon crystal, whereas polycrystalline cells are made up of fragments or shards of silicon. Mono formats provide more room for electrons to move around and thus offer a higher efficiency solar technology than polycrystalline, though they are typically more expensive.

How Solar Panels Are Made?

How solar panels are made

The main component of any solar panel is a solar cell. Specifically, a number of solar cells are used to build a single solar panel. These cells are the part of the device that converts sunlight into electricity. Most solar panels are made from crystalline silicon-type solar cells. These cells are composed of layers of silicon, phosphorous, and boron (although there are several different types of photovoltaic cells). These cells, once produced, are laid out into a grid pattern. The number of these cells used depends largely on the size of the panel being created, as many different sizing options exist.

Once the cells are laid out, the panel itself is sealed to protect the cells within and covered with non-reflective glass. This glass protects the solar cells from damage, and is non-reflective to ensure sunlight can still reach the cells. Once sealed, this panel is placed into a rigid metallic frame. This frame is designed to prevent deformation, and includes a drainage hole to prevent water from building up on the panel as a buildup of water could reduce the efficiency of the panel. Additionally, the back of the panel is also sealed to prevent damage.

How Does Solar Panel Work?

How solar panels work

Solar panels work by letting photons from the sun's rays knock electrons free from atoms inside of photovoltaic cells (PV cells) to generate a flow of electricity. The main part of the solar panel that does this is the photovoltaic (PV) cell. Each solar panel has 60 or so PV cells connected together that convert sunlight into electricity. Multiple panels (modules) can be wired together to form a solar array. The more panels you can deploy, the more energy you can expect to generate.

Inside each PV cell are two thin layers of silicon sandwiched between two metal contacts. When sunlight hits the top layer of silicon, its electrons are 'excited' into flowing down towards the bottom layer as a direct current (DC). With the help of the metal contacts, this movement becomes an electrical circuit. This process is called the photovoltaic effect, and is the foundational chemical and physical process behind the vast majority of solar technology.

But this isn't enough to power a home. Household appliances can't use this type of electricity and so it needs to be converted into a different kind of current. Here's where the inverter comes in. An inverter converts the direct current (DC) produced by your solar panels into the alternating current (AC) that your electrical appliances need to work. It's probably the most important part of the whole system.

How Do Solar Panels Generate Electricity?

PV solar panels generate direct current (DC) electricity. With DC electricity, electrons flow in one direction around a circuit. This example shows a battery powering a light bulb. The electrons move from the negative side of the battery, through the lamp, and return to the positive side of the battery.

Principle of powering a light bulb

With AC (alternating current) electricity, electrons are pushed and pulled, periodically reversing direction, much like the cylinder of a car's engine. Generators create AC electricity when a coil of wire is spun next to a magnet. Many different energy sources can "turn the handle" of this generator, such as gas or diesel fuel, hydroelectricity, nuclear, coal, wind, or solar.

AC electricity was chosen for the U.S. electrical power grid, primarily because it is less expensive to transmit over long distances. However, solar panels create DC electricity. How do we get DC electricity into the AC grid? We use an inverter.

A solar inverter takes the DC electricity from the solar array and uses that to create AC electricity. Along with inverting DC to AC power, they also provide ground fault protection and system stats, including voltage and current on AC and DC circuits, energy production and maximum power point tracking.

How Long Do Solar Panels Last?

Solar panels are surprisingly durable — they can last up to 25 years or more with little to no maintenance. Electrons are the only moving part in a solar cell, and they all go back to where they came from. In order to maintain optimum output, though, you'll want to regularly clean your solar panels and have any damaged panels replaced.

Most solar panel manufacturers predict a degradation rate of about 0.8% every year. After 20 years, solar energy production should be around 84% of the efficiency standard. Typically, residential panels come with a performance warranty that lasts between 10 and 25 years, which may not cover the full life span of your system.

Final Words

The solar energy market is constantly evolving and changing to meet the growing demands for renewable energy. Installing a solar energy system in your home is a sustainable way to decrease your energy costs and carbon footprint. Solar panels have no moving parts and require little maintenance. They are ruggedly built and last for decades when properly maintained.