Sources of electricity are everywhere in the world. Worldwide, there is a range of energy resources available to generate electricity. These energy resources fall into two main categories, often called renewable and non-renewable energy resources. Each of these resources can be used as a source to generate electricity, which is a very useful way of transferring energy from one place to another such as to the home or to industry.
Sources of electricity can include coal, which mainly consists of carbon atoms that come from plant material from ancient swamp forests. It is a black solid that is reasonably soft. You can scratch it with a fingernail. It is not as soft as charcoal, however, and is quite strong.
It can be carved into shapes. There are different types of coal. Some contain impurities such as sulphur that pollute the atmosphere further when they burn, contributing to acid rain.
How was it formed?
Millions of years ago, trees and other plants grew rapidly in a tropical climate, and when they died they fell into swamps. The water in the swamps prevented the plant material from decaying completely and peat was formed.
As time passed, layer upon layer of peat built up. The pressure from these layers and heat from below the Earth’s crust gradually changed the material into coal.
Coal can be found in parts of the world that were once covered with swampy forests, such as the UK about 250 million years ago. There are large deposits in China, USA, Europe and Russia. South Africa also has relatively large deposits.
When coal burns it produces mainly carbon dioxide, some carbon monoxide and soot (which is unburned carbon). Many coals when burned produce smoky flames.
Their energy content weight for weight is not as great as oil. When coal burns it produces more carbon dioxide than oil.
Advantages
Coal is relatively cheap, with large deposits left that are reasonably easy to obtain, some coal being close to the surface. It is relatively easy to transport because it is a solid.
Disadvantages
Some sources of coal are deep below the ground, as in the UK. They can be difficult, costly and dangerous to mine.
Burning coal without first purifying it contributes to global warming, as well as to the production of smog (smoke and fog), which is harmful to health. It is a finite resource and will eventually run out.
