NCERT · Class 10 · Science · Sources of EnergyWhy are some sources of energy classified as renewable while others are non-renewable? Give examples of each.

The classification of energy sources into renewable and non-renewable categories depends entirely on their rate of replenishment and their ultimate availability on Earth relative to human consumption rates. \nRenewable sources of energy are those that are inexhaustible, constantly being replenished by natural processes, and will not run out even with continuous long-term use. Nature continuously regenerates these sources at a pace equal to or faster than their consumption. Examples include solar energy, wind energy, hydroelectricity, tidal energy, and geothermal energy. \nIn contrast, non-renewable sources of energy are those that exist in finite, limited quantities on Earth. Once these reserves are completely exhausted through human consumption, they cannot be regenerated or replenished within a human lifetime, as their formation takes millions of years of geological processes. Examples of non-renewable sources include fossil fuels such as coal, petroleum, and natural gas, as well as nuclear fuels like uranium.