Guide to How Solar Panels Work

Introduction

In this guide we will look in detail at how a solar panel works. Using a step-by-step guide on the process of generating electricity from sunlight.

Firstly, solar panels work through a process called the photovoltaic effect. This enables the panels to convert sunlight into electricity that we can use in our homes, businesses, organisations, and communities.

Photovoltaic

Photo – Light

Voltaic – Volts or electricity

Section 1 – How it works

  1. Sunlight Absorption
    Solar panels are made up of a number of solar cells, which are usually comprised of silicon. They are made of silicon to reduce costs, increase efficiency, and increase the solar panel’s lifespan. When sunlight hits the solar panel, photons, which are particles of light, are absorbed by the silicon cell.

Solar Cell

A device, on solar panels, that converts sunlight directly into electricity

      1. Electron Excitation
        The photons that are absorbed transfer their energy to the electrons within the silicon atoms. This causes the electrons to become excited, giving them higher energy levels, which allows them to break free from their atoms.
      2. Electric Field
        The structure of the solar cell then creates an electric field. This electric field, which is formed by the combination of different layers within the cell, guides the free electrons in a specific direction.
      3. Electron Flow
        The free electrons move within the cell, under the influence of the electric field which guides them in a specific direction. This movement creates a flow of electrons, which generates an electric current. This current is known as a DC or direct current of electricity.
      4. Current Collection
        Metal conductive plates that are on the top and bottom of the solar cell collect the current that is being generated and transfer it out of the cell. To increase the overall voltage output multiple solar cells are connected in a series.
      5. Inverter Conversion
        The direct current (DC) electricity that is generated by the solar panel is sent to an inverter. The role of the inverter is to convert the DC electricity into an alternating current or AC. AC electricity is the type of electricity that can be used to power our homes, businesses, organisations, and communities, as well as our electrical devices and appliances.
      6. Electrical Grid Connection
        This AC electricity can either be consumed directly within the premises or it can be fed into the electrical grid. With grid-connected systems, any excess electricity that is generated by solar panels can be exported to the grid. If solar generation is insufficient, electricity can be imported from the grid.
      7. Energy Consumption
        The AC electricity is then used to meet the energy needs of the property. A net metering system can also be added to track the energy exchanged between the solar panel system and the electrical grid.

The efficiency and the output of the solar panels can be affected by several factors including the intensity of the sunlight, the angle the solar panel is installed, and how shaded the area is. Optimal performance and longevity can be ensured with proper installation, regular maintenance and monitoring of the system.

Section 2 – The layers of a solar panel

There are a number of layers that make up the solar panels, these are:

  1. Top Transparent Layer
    This layer is typically made of glass or a transparent polymer. This layer is to protect the panel from any external factors that could damage it, whilst also allowing sunlight to pass through it.
  2. Antireflective Coating
    This is applied on top of the transparent layer. This coating reduces reflection and enhances light absorption to improve the efficiency of the panel.
  3. Semiconductor Layer (Active Layer)
    This layer is typically made of crystalline silicon or a thin-film material, such as cadmium telluride (CdTe) or copper indium gallium selenide (CIGS). This layer absorbs the photons from the sunlight and generates electricity through electron excitation.
  4. Back Contact Layer
    This layer is located at the back of the semiconductor layer. This helps to facilitate the flow of electrons within the solar panel.
  5. Encapsulant
    This layer is made up of a transparent material that encapsulates the semiconductor layer. It protects the semiconductor layer from moisture, dust, and mechanical damage. The material used is usually ethylene-vinyl acetate (EVA).
  6. Back sheet
    The back sheet is located at the back of the solar panels, and it provides further protection to the solar panels from environmental factors. It also serves as an electrical insulator.
  7. Frame
    This is the outermost layer, and it is usually made from aluminium or steel. The frame provides structural support, rigidity, and protection for the entire solar panel assembly.

Be aware that depending on the type of solar panel and the manufacturer, specific composition and layer arrangement may vary.

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