What is solar energy
Solar energy is radiant energy that is produced by the sun. Every day the sun radiates, or sends out, an enormous amount of energy. The sun radiates more energy in one second than people have used since the beginning of time! Where does the energy come from that constantly radiates from the sun? It comes from within the sun itself. Like other stars, the sun is a big ball of gases––mostly hydrogen and helium atoms.
The hydrogen atoms in the sun’s core combine to form helium and generate energy in a process called nuclear fusion. During nuclear fusion, the sun’s extremely high pressure and temperature cause hydrogen atoms to come apart and their nuclei (the central cores of the atoms) to fuse or combine. Four hydrogen nuclei fuse to become one helium atom. But the helium atom contains less mass than the four hydrogen atoms that fused. Some matter is lost during nuclear fusion. The lost matter is emitted into space as radiant energy. It takes millions of years for the energy in the sun’s core to make its way to the solar surface, and then just a little over eight minutes to travel the 93 million miles to earth. The solar energy travels to the earth at a speed of 186,000 miles per second, the speed of light.
Only a small portion of the energy radiated by the sun into space strikes the earth, one part in two billion. Yet this amount of energy is enormous. Every day enough energy strikes the United States to supply the nation’s energy needs for one and a half years! Where does all this energy go? About 15 percent of the sun’s energy that hits the earth is reflected back into space. Another 30 percent is used to evaporate water, which, lifted into the atmosphere, produces rainfall. Solar energy also is absorbed by plants, the land, and the oceans. The rest could be used to supply our energy needs.
How to convert solar energy into power
Energy from the sun can be converted into solar power in two ways. The first way involves the use of solar thermal applications. Solar thermal applications use the sun’s energy to provide direct heat to air or liquid (like Thermosyphon solar water heater). Solar thermal panels can be used for both residential and larger-scale applications.
The second way of obtaining solar power involves the use of photoelectric applications. Photoelectric applications use photovoltaic cells in converting energy from the sun into electricity. Photovoltaic cells are considered low maintenance and well suited to remote applications. They use semiconductors like silicon to convert energy from the sun into electricity.