Sources of Biomass
Land crops: Lignocellusic material from trees of Eucalyptus, Poplar, Firs, Pines, Leucaena and starch crops like maize, cassava and sugar crops like cane and beet.
Aquatic plants: Unicellular algae, multicellular algae, aquatic weeds like water hyaiinth, hydrilla etc.
Wastes: Like manure, domestic rubbish, municipal waste / sewage.
Agro-industrial wastes: Wood and crop residues like straw, husks, citrus peels, molasses, willow dust, press mud, paper sludge etc.
Biomass resources can be divided into three categories:
(i) Biomass in its traditional form or solid mass (wood & agricultural waste): In this category, energy is obtained by burning the biomass directly.
(ii) Biomass in its non-traditional form: In this category the biomass is converted into methanol or ethanol.
(iii) In the third category, biomass in its gaseous form: In this category biogas is produced from anaerobic fermentation of biomass.
Advantages of Biomass as a source of energy
(i) Storage is possible.
(ii) Transportation possible.
(iii) It is renewable.
(iv) High energy fuels can be obtained.
(v) Low capital input required.
(vi) Can be developed with present man and material abilities.
(vii) It is ecologically safe and is inoffensive.
(viii) It does not increase C02 content of the atmosphere.
Disadvantages
(i) Land and water use competition.
(ii) Solar energy a source of biomass is diffuse and intermittent.
(iii) Collecting and storing it is bulky and costly.
(iv) Supply uncertainty initially.
(v) Costs uncertain.
(vi) Fertilizer, soil, water required.
(vii) Low conversion efficiency (per cent solar energy trapped.)