Solar panels are a great way to generate your own electricity using the power of the sun, helping you save money on your energy bills and reduce carbon emissions – paving the way for a greener, more sustainable future. But have you ever wondered how solar panels actually work?
Photovoltaic Effect (PV)
Solar panels convert light energy, gained from the sun, into electrical energy in a process called the photovoltaic effect. Solar panels are made up of individual solar cells – this is where the photovoltaic effect takes place. The majority of modern solar cells are constructed of monocrystalline-silicon, a semi-conducting material. When sunlight, composed of particles called photons, hits the solar cell, the photons transfer energy to the electrons of the semi-conducting material.
These electrons then become excited, reaching a higher energy state. The electron is then ejected out of the material, leaving behind a gap. This represents the flow of electrons and is how an electrical current is generated.
Monocrystalline-Silicon
Monocrystalline-silicon is currently the first choice for solar panel construction. It consists of pure silicon and has a continuous, unbroken chemical structure called a crystal lattice. Silicon is the second-most abundant element in the Earth’s crust, making it readily available and cheap to produce. It has a relatively small band gap, meaning less energy from the sun is required to excite electrons in order to reach their higher energy state. Silicon also has the unique ability to be doped with other elements, in order to alter its electrical properties. Monocrystalline-silicon is cut into thin wafers to be used in solar cell production.
N-type and P-type Semiconductors
Monocrystalline-silicon wafers are doped intentionally to produce two different types of semi-conductor; N-type and P-type. The ‘N’ stands for negative and the ‘P’ stands for positive.
N-type semiconductors are created by doping with an element with an excess of electrons, ready to give away, such as phosphorous. P-type semiconductors are created by doping with an element with an excess of spaces, e.g. boron, ready to receive electrons from the N-type material. N-type and P-type semiconductors are joined together to create a p-n junction, which generates an electric field as electrons move from the negative side to the positive side.
Electricity Generation
Using the photovoltaic effect, solar panels are able to produce a direct current (DC) which must be converted into alternating current (AC) before being used for electrical appliances. This process occurs within an inverter. For further information on how a solar PV system is setup, please click contact us and we can run through the configuration of a system
Solar panels are a renewable source of clean energy, helping to not only reduce carbon emissions and save the environment, but also lower your monthly electricity bill. Adding a battery to your system is a great way to store this clean energy for later use, or when the sun goes in.
Glossary:
- Light Energy – A form of electromagnetic radiation that travels in waves. The only form of energy visible to the human eye.
- Electrical Energy – A type of kinetic energy caused by the movement of electrons. The faster the electrons move, the more energy they carry.
- Photovoltaic Effect – The process that generates voltage or an electric current when a photovoltaic cell is exposed to sunlight.
- Monocrystalline-Silicon – A material formed completely of pure silicon, used in virtually all electrical equipment.
- Semi-conductor – A material that has an electrical conductivity value higher than that of an insulator (e.g. glass) but less than that of a conductor (e.g. copper).
- Photons – A tiny, massless particle that makes up light and other forms of electromagnetic radiation.
- Electron – Sub-atomic particle that has a charge of -1.
- Electrical Current – The flow of charged particles.
- Crystal Lattice – Repeating 3D pattern of atoms, forming a crystal.
- Band Gap – The distance between the valence band of electrons and the conduction band.
- Valence Band – The outermost band of electron orbitals around the atom that electrons are able to jump out of, when they reach a higher energy state.
- Conduction Band – The band of electron orbitals that electrons can jump into from the valence band, when excited.
- Doping – Process of adding trace amounts of impurities to alter a semi-conductor’s electrical properties.
- N-Type Semiconductor – Semiconductor containing an excess of electrons. Usually created, in this case, by adding phosphorous.
- P-Type Semiconductor – Semiconductor containing an excess of spaces. Usually created, in this case, by adding boron.
- P-N Junction – The point at which an N-Type and a P-Type semiconductor meet.
- Direct Current – Flow of electron charge is always in the same direction.
- Alternating Current – Flow of electrons constantly switches back and forth.
- Renewable Energy – A source of energy that does not deplete and is able to replenish itself (solar, wind, hydro, nuclear, geothermal, tidal and wave).
