Fossil fuels are nonrenewable sources of energy. These nonrenewable sources of energy (like coal,petroleum, natural gas) are present in a limited amount in the earth. Once exhausted, they will not be available to us again.
The sun is the source of all energy. The sun is a renewable source of energy. It provides us heat and light energy free of cost. The energy obtained from the sun is called solar energy. The energy coming from the sun contains heat rays, visible light, ultraviolet (UV) rays and some gamma rays.