What is solar energy?

Source of Solar Energy

Solar energy comes from within the sun itself. Like any other star in the universe, our sun also acts like a giant nuclear reactor. It is a big ball of gas that consists mainly of hydrogen and helium. The energy of the sun originates from its core by a process known as nuclear fusion. During fusion, the extremely high temperature and pressure conditions cause the hydrogen atoms to split, and their nuclei (core of the atoms) combine and form one helium atom. Subsequently, a lot of radiant energy is emitted as a byproduct of nuclear fusion. This radiant energy travels a distance of 93 million miles in about eight minutes to the earth’s surface.

Amount of Radiant Energy Absorbed

Not all radiant energy sent to earth gets received on its surface; around 15% is reflected back to space by the earth’s surface. Of the remaining energy, 30% gets consumed in water evaporation, which is an important phenomenon for maintaining the water cycle. Plants and oceans also absorb some part of this radiant energy. The rest of it can be used to fulfill our growing energy needs.

Solar energy can be used to power a number of devices for commercial and non-commercial use. Two main types of solar energy technologies that make it possible to harness solar energy effectively are photovoltaic (PV) and concentrating solar power (CSP).