Biomass, a renewable energy source, is biological material from living, or recently living organisms, such as wood,
waste, (hydrogen) gas, and alcohol fuels. Biomass is commonly plant matter grown to generate electricity or produce heat.
The most conventional way in which biomass is used is by direct incineration. Forest residues, for example (such as dead trees,
branches and tree stumps), yard clippings, wood chips are often used for this. However, biomass also includes plant or animal
matter used for production of fibers or chemicals.
Biomass may also include biodegradable wastes that can be burnt as fuel.
It excludes such organic materials as fossil fuels, which have been transformed by geological processes into substances
such as coal or petroleum.