If you’ve ever wondered how sunlight can give you electricity, be prepared to find out. Here’s the mildly technical explanation of where all that power comes from.
History of Solar Electricity
Did you ever play in Science class with an accumulator, or battery, made up of two electrodes in a liquid? Well, ages ago a Frenchman called Becquerel was doing something similar, and he noticed that the battery’s output varied depending whether the electrodes were exposed to light. This was the first noting of what’s called the photoelectric effect. A while later, but still in the 19th century, an experimenter, William Adams, discovered that an element, called selenium, produced a very small amount of electricity when exposed to light – this wasn’t very interesting, as the power was too little to do anything useful. However, in 1883 an American, Charles Fritts, used this effect to produce the first real solar cell.
Science of Solar Electricity
If you did Science, then you’re familiar with the basic concept of an atom – a core, made up of neutrons and protons (with a positive charge), and electrons (with a negative charge) circling round. You may also have heard of the theories about light – at one time it was thought to be an electromagnetic wave, but then the scientists decided that it was actually discrete particles, called photons, that made up light. Photons, by the way, have no mass and move at 186,000 miles per second, the speed of light.
The theory goes that a photon in the light hits an electron in the atom of certain materials, and knocks it out of the atom. This immediately makes the atom positive, and the loose electron is negative. Almost as immediately, the atom becomes neutral again, as it attracts the electron back – unless there is a way that the charge is carried away to do work. Photovoltaic cells have such a way – a grid or conductor on the face.
Solar electricity Today
If you’re wondering how we came to a level of development of solar cells that they can actually power a house, then we must just mention a couple of other breakthroughs. In the 1950s, Bell Laboratories were playing with the new semiconductor materials, and accidentally discovered that silicon could be used to make the first practical solar cell, that could be used to power something. The space program helped speed the development of solar cells, which were used for satellites and spacecraft, and further development with other materials brought us to the current stage, which has fully useful although still somewhat expensive solar cells available for the general public to buy.