What is an example of a non-renewable energy source?

Coal is classified as a non-renewable energy source because it is a fossil fuel formed over millions of years from the remains of ancient plants and animals. The process of forming coal involves geological changes and the accumulation of organic material under heat and pressure over extensive time periods. As a result, once coal is extracted and used for energy, it cannot be replenished on a human timescale.

In contrast, renewable energy sources, such as solar energy, wind energy, and hydro energy, can be naturally replenished. Solar energy harnesses sunlight, wind energy captures the movement of air, and hydro energy utilizes the flow of water. These sources can continually produce energy as long as natural conditions persist, making them sustainable over the long term. This fundamental difference in how these energy sources are formed and utilized highlights why coal stands out as a non-renewable option.