What is the source of energy in fossil fuels?
The source of energy in fossil fuels primarily comes from ancient organic matter, such as plants and animals, that lived millions of years ago. When these organisms died, their remains were buried under layers of sediment. Over time, the pressure and heat from the Earth's crust caused the organic matter to undergo chemical reactions, transforming it into fossil fuels, namely coal, oil, and natural gas.
To understand the source of energy in fossil fuels, it is helpful to know about the process of photosynthesis. Plants, through photosynthesis, convert sunlight, carbon dioxide, and water into glucose (a type of sugar) and oxygen. This glucose serves as the energy source for the plant and gets stored in its tissues.
When plants and animals die, their organic matter decomposes, but sometimes it gets buried under sedimentary layers without fully decomposing. Over millions of years, layers of sediment pile up, exerting immense pressure and increasing temperature deep within the Earth.
Under these high pressures and temperatures, the organic matter undergoes chemical changes called diagenesis and catagenesis. During these processes, the complex organic molecules in plants and animals break down and transform into simpler hydrocarbons, which are the main components of fossil fuels.
In essence, the source of energy in fossil fuels is the potential energy stored in the chemical bonds of the hydrocarbons that make up coal, oil, and natural gas. When fossil fuels are burned or combusted, the chemical bonds are broken, releasing energy in the form of heat and light. This energy can be harnessed to generate electricity, power vehicles, and provide heat for various purposes.