What is often considered a non-renewable source of energy?

Natural gas is categorized as a non-renewable source of energy because it is derived from fossil fuels that were formed over millions of years from the remains of ancient plants and animals buried under layers of sediment and rock. Once extracted and used for energy, these resources are not replenished on a human time scale, leading to their eventual depletion.

In contrast, wind energy, solar energy, and geothermal energy are renewable. Wind and solar energy rely on natural phenomena that are continuously replenished—sunlight and wind—while geothermal energy derives from the Earth's internal heat, which is also sustainably available. Therefore, selecting natural gas identifies a key distinction in energy sources, highlighting the importance of understanding the sustainability of energy production and consumption.