Energy sources can be classified into two types: renewable and nonrenewable. Nonrenewable resources, such as fossil fuels and nuclear material, are removed from the earth and can be depleted. These resources have been the most used type of energy in the modern era. Renewable energy is also known as alternative energy source which comes from natural resources such as sunlight, wind, water and geothermal heat. In the early part of the twenty-first century, renewable sources have become more popular as nonrenewable sources have begun to be depleted. Alternative sources will be needed within next fifty years.
There is variety of renewable energy sources and most common energy sources are solar energy, wind energy and hydro energy.
Solar energy is derived from the sun's rays. Solar energy is converted directly to electricity through solar photovoltaic panels. Solar rays, collected off reflective surfaces, heat an object in a process that creates solar thermal energy. There are several types of solar appliances. The most common device is a solar panel. The solar panel is usually used as electric energy for home. It is mounted on the roof of the house to get the most sunlight. Unfortunately people cannot afford to have their own solar technology at home because solar technology is still very expensive and does not provide sufficient energy for today. Moreover, some scientists believe that the solar panel absorbs the sun radiation and destroys ozone layer.
Wind energy can be created from the movement of the wind. Wind is created over the earth's surface due to uneven heating patterns of the atmosphere. When the wind is caught in mill propellers, the propeller shaft is forced to rotate and turn a generator creating electricity. Wind power energy has also been used for more than thousand years to do simple tasks such as pumping water and grinding grain. The cost of wind technology is higher than paying for traditional electric provider. However Wind power energy has not stopped. Wind power energy can be enough to be used for residential purposes. Only Wind power energy counts as safest, harmless to environment energy source. It is considered to be a clean energy source.
Hydro energy can be obtained