Which of the following is an example of a non-renewable energy source?

Coal is classified as a non-renewable energy source because it is formed from the remains of ancient plants and requires millions of years to develop. Once coal is extracted and used, it cannot be replenished in a human timescale, which means once it is depleted, it is gone forever.

In contrast, wind and solar energy are renewable sources, as they can be harnessed continually as long as the natural conditions (wind and sunlight) are present. Biomass, while sourced from organic materials, can also be considered renewable if it is managed sustainably, as new plants can be grown to replace those used. However, coal remains a finite resource that contributes to environmental issues when burned, making it a key example of non-renewable energy.