Coal, crude oil, and natural gas are useful because they are energy-rich, reliable fuels with established infrastructure. However, all are finite fossil fuels, and their combustion contributes to climate change and air pollution, with natural gas generally producing less carbon dioxide per unit of energy than coal.
Advantages and Disadvantages
| Fuel | Advantages | Disadvantages |
|---|---|---|
| Coal | Abundant in many countries; relatively inexpensive; easy to store and transport as a solid; provides reliable energy without depending on weather conditions. | Produces the most carbon dioxide per unit of energy of the three fuels; may contain sulfur impurities that form sulfur dioxide; incomplete combustion can produce carbon monoxide and particulates; mining damages habitats and landscapes. |
| Crude oil | High energy density; easier to transport than coal through pipelines and tankers; can be separated by fractional distillation into useful fuels such as gasoline, kerosene and diesel. | Produces carbon dioxide when burned; incomplete combustion produces carbon monoxide and soot; sulfur impurities may produce sulfur dioxide; oil spills damage aquatic ecosystems; reserves are finite. |
| Natural gas | Mainly methane, which has a high hydrogen-to-carbon ratio; produces less carbon dioxide per unit of energy than coal or oil; burns relatively cleanly, producing little soot or sulfur dioxide. | Still produces carbon dioxide; methane leaks are serious because methane is a potent greenhouse gas; difficult to store and transport because it is a gas, unless compressed or liquefied; extraction can damage ecosystems. |
During complete combustion, hydrocarbon fuels form carbon dioxide and water. For methane:
