Natural gas is the product of millions of years of decay. Dead plants, trees, animals and sea creatures that existed hundreds of millions of years ago have long since decomposed, creating thick layers of soil and mud, which over time have become rock. Centuries and centuries of pressure and heat then turned this organic matter into coal, oil and gas – also known as fossil fuels.
In some areas, gas escapes naturally from the gaps in rocks and is released into the air. Scientists quickly got to grips with the potential of this gas and realised that there were vast energy resources beneath the ground waiting to be extracted.
Nowadays, when a company is looking for natural gas, they look for certain types of rock formations above the ground. Measuring sound waves and gravitational pulls also gives clues about where these pockets of natural gas lie.
Once a natural gas reserve has been discovered, wells are dug around 6,000 feet into the ground, and the gas is extracted by pipelines and sent to power plants and factories where by-products such as butane and propane are separated, and chemicals are added to the gas to give it its unpleasant sulphur smell (it’s naturally odourless, so the smell is added to help us detect leaks).
However, as clean and useful as this kind of natural gas is, it’s not renewable, so it won’t be around forever. But newer technologies such as biogas generation are getting ready to take the place of natural gas, instead. Here, processing plants use anaerobic digestion to turn organic material such as wood, plants and grass into a form of gas. The process is basically the same, it’s just considerably faster!