Energy exists freely in nature. Some do exist infinitely (never run out, called RENEWABLE), and the rest have finite amounts (they took millions of years to form, and will run out one day, called NON-RENEWABLE).

Non-renewable energy is energy from fossil fuels such as coal, crude oil, natural gas, and uranium. Fossil fuels are mainly composed of carbon, formed 300 million years ago when the earth was a lot different in its landscape. Scientists believe that the earth had swampy forests and very shallow seas. That period is known as the Carboniferous Period.

Fossil fuels are usually found in one location as their formation is from a similar process. Let us take a look at the diagram below to see how fossil fuels formed.

1. Millions of years ago, dead sea organisms, plants, and animals settled on the ocean floor and inside porous rocks. This organic matter had stored energy in them as they used the sun’s energy to prepare foods (proteins) for themselves (photosynthesis).

2. With time, sand, sediments, and impermeable rock settled on the organic matter, trapping its energy within the porous rock. That formed pockets of coal, oil, and natural gas.

3. Earth movements and rock shifts create spaces that force to collect these energy types into well-defined areas. With the help of technology, engineers can drill down into the seabed to tap the stored energy. This stored energy is commonly known as crude oil.

• The good thing is about fossil fuels is:
  Unlike many renewable energy sources, fossil fuels are relatively less expensive to produce, hence its higher demand as it tends to cost less.
  
  
• The bad thing about fossil fuels is:
  Fossil fuels are made up mainly of carbon. When burned (used), they produce carbon compounds (carbon dioxide and other greenhouse gases) that hurt the environment in many ways. Air, water, and land pollution are all consequences of using fossil fuels.

Now we shall look at what each source of non-renewable energy is and how they are harnessed.

Note that not all non-renewable energy comes from fossil fuels. There is also uranium, which is not a fossil fuel.