Solar energy is a hot topic. More and more experts consider solar to be “the king of renewables” and put a lot of trust in it. But what exactly is solar energy and how do solar panels work? In this short article we’ll talk about the very basics of solar energy.
What is solar energy?
The sun is a giant natural nuclear fusion reactor. The protons or hydrogen atoms inside the star collide and fuse into helium. This results in massive amounts of energy produced which reaches us in the form of electromagnetic radiation. Photons from the sun land on Earth and in the 19th century humans accidentally discovered a way to convert them into plain electricity. The “the photovoltaic effect” was discovered and it is the very secret behind how solar panels work.
The photovoltaic effect explained
There are certain materials that produce current when they are hit by the light. These materials are known as semiconductors. The whole photovoltaic industry is built upon a so-called photovoltaic effect. Solar cells of the panels are mostly made of silicon which is one of the known semiconductors.
A solar cell has two layers of silicon inside of it. They are treated with phosphorus and boron to create a negative and positive side. Between them an electric field occurs. The electrons from this field are collected by metal plates and from there the current flows through the wires into the inverter and power your house.
Alternatives to silicon solar cells
Although 95% of solar cells are made out of silicon, it’s not the only material that can be used:
- Thin-film solar panels can be made out of different chemicals such as amorphous silicon, Gallium Arsenide or Cadmium Telluride. Thin-film panels are much lighter, but they are less efficient than rigid panels with standard silicon cells.
- Organic solar cells are made of carbon-based materials. They are also known as plastic cells. To make them, engineers dissolve organic compositions in ink and print them on plastic.
Additional important parts to solar panels
Standard solar cells can be either monocrystalline and polycrystalline. Mono-cells are made out of a single silicon crystal, whereas poly-cells are made out of lots of silicon fragments that are melted together. Mono-cells are by far the most efficient and popular type of solar elements today.
Solar cells usually have busbars which are thin metal ribbons that are laid across cells. They conduct current which is why they are usually made of copper. Some manufacturers, like Trina Solar, replace them with thin wires, because ribbons slightly shade solar cells.
Of course, solar cells have to be protected. This is why each panel has a frame made of anodized aluminum and a layer of tempered glass on the front side. The glass is treated with an anti reflective coating so that it doesn’t get in the way of energy production.