Potential solar energy is energy stored in the sun, which can be converted to other forms of energy. Only a very small fraction of the energy available to us on earth from the sun is trapped and used by humans. Most renewable energy sources available on the planet originate from the energy of the sun. The only exceptions to this are geothermal and tidal energy.
Potential solar energy arrives at the surface of the earth in the form of waves of light, which have traveled from the sun through space. The wavelengths of this solar energy vary, with most of the light being in the infrared or visible ranges and some in the ultraviolet range. When light waves arrive at the earth’s atmosphere, about a third of the energy is reflected back into space. The remainder of the energy is absorbed by the atmosphere, clouds, land, and the sea.
Some of the potential solar energy that is absorbed by the earth is converted into other forms of energy that can be used by humans to generate power. Solar energy causes water to evaporate, which contributes to air movements such as wind. Wind power can be used to generate electricity.
Even the power created by burning fossil fuels originally comes from solar energy. Photosynthesis by plants traps the potential solar energy and converts it to chemical energy, which creates new carbon based matter. In this way plant matter, food, wood, and animal matter all originate ultimately from the solar energy of the sun.
As well as using potential solar energy indirectly by burning fossil fuels or using wind and other natural phenomena to generate electricity, humans also trap some solar energy and directly convert it to electricity. One of the main technologies used to do this is photovoltaics. At the atomic level, photovoltaics works because certain materials have the ability to absorb light waves and then release electrons. The electrons that are released can be captured as an electric current. Silicon is one such type of material.
The science of photovoltaics was first discovered as long ago as 1839. For over a hundred years, the technology was too expensive to have any widespread use. In the 1960s, potential solar energy was used to create power on spacecraft. Modern technology has now advanced to a point where potential solar energy can be tapped efficiently, leading to many personal and commercial applications.