Energy

What is it?

Oil is a fossil fuel, just like coal and natural gas. Such fuels derive from the rests of plants and animals which died hundreds of million years ago, when mankind had not yet appeared on Earth. Those plants and animals, as it happens today, have accumulated the energy coming from the Sun and, after their death, have remained buried for millions of years until they have turned into oil and coal. Prehistoric animals and plants today return the solar energy they accumulated in the past as heat and electric energy. Great part of the energy we use today comes from fossil fuels, especially oil. However, it is a non-renewable energy source which is bound to depletion sooner or later. More specifically, oil is a natural mixture of liquid hydrocarbons and other substances of fossil origin contained in sedimentary rocks and associated to smaller quantities of gaseous (natural gas) and solid (bitumen) hydrocarbons. All the molecules of the existing hydrocarbons include two types of atoms only: carbon and hydrogen atoms. According to the quantity of carbon atoms included in the molecule, hydrocarbons can be in gaseous (up to 4 atoms), liquid (from 5 to 16 atoms) or solid state (over 16 atoms).