The term "biomass" refers to any form of plant or animal tissue. In energy industry biomass refers to wood, straw, biological waste products such as manure and other natural materials that contain stored energy. In one sense, biomass is also a form of solar energy. Since, various forms of plant are using the solar energy in day time to fix the carbon from the atmosphere into it. The energy stored in biomass can be utilized by directly burning or feeding it to micro-organism which in turn produces biogas, which is a form of natural gas. Direct burning is practiced by mankind for thousands of years for cooking and heating.
But the process of direct burning is inefficient and causes emission of green-house gases. Therefore, more efficient method like biomass gasification, paralysis etc. are more widely used in decentralized power generation and remote area electrification.