Sunlight falling on the earth's surface equals 50,000 times the energy used each year by man. Almost all our energy comes from sun.
The sun's nuclear energy is responsible for the tidal energy, heat energy stored in water, the chemical energy stored in plants, and the kinetic energy stored in the wind, from which we can obtain electrical energy.
This is the indirect use of solar energy. We can also harness solar energy directly. The world is rediscovering the most readily available fuel source of all. Solar water heater and solar cells are some of them.
