EnergyEnergy is the capacity for doing work, either in motion (kinetic) or stored up (potential). It can cause or causes motion.
The whole Universe is filled with energy. It is energy that keeps this Universe going. This energy is manifested in force, light, heat etc.
Energy resources are of two types - renewable as well as non-renewable.
Renewable (or in exhaustible) Energy Resources are mostly bomass based and available in unlimited amount in nature, since these can be renewed over relatively short period of time. These include, firewood (or fuel wood) obtained from forests, pertroplants, plant biomass (as agricultural wastes like bagasse), animal dung, solar energy, wind energy, water energy, geothermal and dendothermal energy etc. These can reproduce themselves in nature and can be harvested continuously through susbtained proper planning and management.
Non-renewable (or exhaustible) Energy Resources are available in limited amount and develop over a longer period. As a result of unlimited use, they are likely to be exhausted one day. These include coal, mineral oil, natural gas and nuclear power. Coal, petroleum and natural gas, the common sources of enrgy, being organic (biotic) in their origion are also called fossile fuels.