ABSTRACT
The term biomass can be applied to materials derived from both animals and vegetables. For biofuels, biomass usually relates to plant based material. The United Nations Framework Convention on Climate Change (UNFCCC) defined biomass as non-fossilized and biodegradable organic material originating from plants, animals and microorganisms (UNFCCCa). Biomass is recognized as natural and renewable resources. The term natural resources means materials and components occurring in nature that can be used for economic production or consumption. The term renewable natural resources stands for natural resources which, after exploitation, can return to their previous stock levels by natural processes of growth or replenishment in the same or lower amount of time (OECD, 2008). Some renewable resources, such as solar energy, wind energy and geothermal pressure have essentially and endless supply, while others, such as plants or animals are considered renewable even though some time or effort must go into their renewal. As the energy comes from the sun, biomass is a renewable energy source and can regrow over a relatively short period of time. According to the UNFCCCb, biomass must meet certain criteria to be classified as renewable. In the last decade, biomass has shown signs of revival because it is considered as renewable, storable, substitutive, abundant and carbon neutral material (Yokoyama, 2008).
