Biomass to Energy

Biomass to Energy

Biomass is organic matter originally derived from plants, produced through the process of photosynthesis, and which is not fossilised (such as coal). Biomass can act as a store of chemical energy to provide heat, electricity and transportation fuels, or as a chemical feedstock for bio-based products.

Biomass resources include wood from plantation forests, residues from agricultural and forest production, and organic waste streams from industry, livestock, food production, and general human activities. Examples are wood chips, sawdust, cotton ginning trash, nut shells, manure and human sewage. This study has focused principally on biomass from trees and then agricultural crops. Other sources of biomass, such as animal and human wastes, are not considered here.

Biomass for energy is a unique form of renewable, solar energy. Of the massive 178,000 x 1012 Watts of solar energy that falls on the Earth's surface, some 0.02% or 40 x 1012 Watts is captured by plants via photosynthesis and bound into biomass energy. This translates into the production of some 220 billion 'dry' tonnes of biomass per year, which as an energy source represents some ten times the world's total current energy use. Currently some 15 percent of the planet's energy requirements are met from biomass, mainly for cooking and heating in developing countries, but also increasingly for fuelling a growing number of large scale, modern biomass energy plants in industrialised countries.

Bioenergy is essentially renewable or carbon neutral. Carbon dioxide released during the energy conversion of biomass (such as combustion, gasification, pyrolysis, anaerobic digestion or fermentation) circulates through the biosphere, and is reabsorbed in equivalent stores of biomass through photosynthesis.

Bioenergy plants can range from small domestic heating systems to multi-megawatt industrial plants requiring several hundred thousand tonnes of biomass fuel per annum each. There are also a variety of technologies to release and use the energy contained in biomass, such as combustion technologies that are well proven and widely used world-wide, and more efficient gasification plants that are currently at the demonstration stage but with potential for significant cost reduction as the technology is commercialised in multiple plants.

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