Energy is the capacity of a physical system to perform work, and it exists in several forms such as heat, light, kinetic or mechanical energy etc. These forms are called energy resources.

These resources can be further classified as

1) Renewable resources- An energy resource that can be replenished naturally over time. As a result, it is sustainable despite its consumption by humans. These types of resources are also known as Green Power because they does not emit harmful particles and gases in the environment. The most popular renewable resources are solar energy, wind power, hydro power, sea current, biomass, photolysis, wave motion etc.

Renewable resources has many advantages. It is a pollution free source, can be stored for extra use, economy friendly, portable, and is widely available for use. But the mechanisms that are used to harvest these sources can come in high costs, and sometimes they collapse also, so it is a disadvantage of using these sources.

2) Non-renewable resources- The natural resources that can not be readily replaced by natural means at a pace quick enough to keep up with consumption are the non-renewable resources.

The most commonly used non-renewable resources, that are used in daily life are Liquids (crude oil, petroleum, hydrocarbon), Gases (natural gases), and Solids (coal, uranium nuclear fuel).

The rapid use of these resources are leading to a great decline of their quantity, and will end very soon at this rate. Also these resources emits toxins and pollutants to the environment when burnt for energy harvesting.

So, to protect the environment, its balance to lead a sustainable life, the renewable resources are now a better option to use in daily life rather than non-renewable resources.