Renewable energy sources should be used more because they are more reliable and have a substantially lower impact on the environment than nonrenewable energy sources. Common renewable energy sources include solar power, wind power, hydropower and geothermal power.
All energy used by humans is simply energy transferred from one form to one that is more useful. For example, the energy from gasoline combustion powers the engine of a car. Renewable energy is generally the best type of energy, but often more expensive. Also, not all renewable energy sources are created equally. Solar power in certain regions of the world is more reliable than others, and also varies during different parts of the year.