Solar Energy
The ultimate source energy is the sun which provides the earth with light, heat and radiation. Every hour the sun radiates onto the Earth more than enough energy to satisfy global energy needs for an entire year.
When sun's energy is harnessed and made useable it is called solar energy. While many technologies derive fuel from one or the other from form of solar energy, there are also technologies that directly transform the sun's energy into electricity.
Solar energy is our earth's core source of renewable energy since generating electricity directly from sunlight does not deplete any of the earth's natural resources and supplies the earth with energy continuously.