While all fossil fuels are generally used for the same purpose, producing energy, there are different types of fossil fuels. Fossil fuels are the hydrocarbon fuels that are found underneath within the Earth. They were produced millions of years ago during the Carboniferous period of history. These fuels are very important to the Earth's population, as most of our energy is produced by their burning. Formed from decayed plant and animal matter that was both compressed and heated underground, fossil fuels are a non-renewable resource because they are no longer being created.

The three major types of fossil fuels are coal, oil and natural gas. Coal has been used for thousands of years since cavemen first began burning it to heat their caves and cook their food. A solid, shiny black substance, coal is a carbon based fuel that became especially important in the 1800s when both the industrial revolution and the locomotive combustion engine relied on its use. Machinery, as well as transportation, grew quickly once coal was found to be a portable and easy to use power source.