Life is sustained by the energy from the sun. Without the sun all plants and animals would die. The sun provides 99.98% of the energy, which naturally flows through the surface environment of the earth. Put another way, the sun supplies 5000 times more energy than all other sources combined. This emphasizes the importance of solar energy to us. Solar energy arrives at the earth at 170 thousand million joules every second! About 30% of the radiation energy is reflected straight back into space. The icecaps and particles in the atmosphere form good reflectors. It is thought that...
to make large scale use practical and the weather makes it unreliable but it does have some applications in electronics where the energy required is small- calculators and radios work well on solar power with a storage or back-up battery. Solar energy is used to power satellites and a 50cm square panel should produce enough energy to run a light.

The advantages of solar energy are that the energy from collector panels is produced quite cheaply. Solar cells are made from silicon. The disadvantages are that they are very expensive and it only works when the sun shines.