Some energy sources need to be harvested extracted from the earth.

The earth contains fossilized remnants of plants and animals that died millions of years ago. These organisms decomposed and became fossilized. After burial and exposure to heat and pressure from the earth, the organic matter is transformed into fossil fuels such as petroleum, natural gas and coal.

 

Some energy sources are derived from other sources.

Electricity can be obtained by transforming another form of energy---like coal, oil, natural gas or wind---into electrical energy. Hydrogen fuel is not naturally available so it must be separated from another substance such as water that is composed of hydrogen and oxygen (H20).

 

 

Some energy sources need to be harnessed.

When the motion caused by wind is captured, it can be converted into electrical energy. The motion of the tides can be translated into electricity or other forms of energy.

Some energy sources are utilized in their natural form.

The sun's energy is absorbed into the roots and leaves of plants enabling them to grow. Some buildings are designed to be naturally heated by the sun's energy.