The amount of energy from the sun that falls on the Earth's surface is enormous. All the energy stored in the Earth's reserves of coal, oil, and natural gas is matched by the energy from just 20 days of sunshine.
Solar energy is a renewable, free source of energy that is sustainable and totally inexhaustible, opposed to fossil fuels, which are finite. It is also a non-polluting source of energy and does not emit any greenhouse gases when producing electricity. The solar electricity that is produced can supplement your entire (or partial) energy consumption.