Biomass appears to be an attractive feedstock for three main reasons. First, it is a renewable resource that could be sustain ably developed in the future. Second, it appears to have formidably positive environmental properties, notably the recycling of carbon in the biological processes, resulting in no net releases of carbon dioxide and a very low sulphur content. Third, it appears to have significant economic potential provided that fossil fuel prices increase, quite substantially, in the future.
Plants absorb energy photosynthetically from the sun producing natural (energy) products as a result. Nevertheless, energy auditing of the production and use of biomass should be continued in order to improve and further understand where energy economies can be made. Biomass as feedstock includes materials that can be converted into various solid, liquid, and gaseous fuels using biological and thermochemical conversion processes.
Four broad categories of potential biomass feedstocks can be identified:
(1) organic urban or industrial wastes;
(2) agricultural crop residues and wastes including manure, straw, bagasse, and forestry waste;
(3) existing uncultivated vegetation including stands of trees, shrubs, bracken, heather, and the like; and
(4) energy plantations, which involve planted energy crops either on wastelands as has been done during our previous investigations or on land brought into production for that purpose, land diverted from other agricultural production, or as catch crops planted on productive land.
Due to the historically poor status of biomass-related R&D, and its neglect on the part of planners and development agencies, it has been very difficult to change biomass energy systems in terms of their production, harvesting, and energy conversion structures to changing socioeconomic and environmental pressures.
Fortunately, this is now changing somewhat, so that there is an opportunity to use biomass efficiently for the production of modern energy carriers such as electricity and liquid fuels and to improve the lack of efficiency associated with traditional biomass fuels such as wood and charcoal.
Ideally a successful biomass program should be sustainable and economical, taking into account all costs and benefits, especially spillover and indirect effects, including environmental and health aspects. The focus of this article is, on effective utilization of biomass at rural as well as urban level in India which will improve, environmental concerns, save foreign exchange, and improve socio economic status of rural India.
SOURCES OF BIO-FUEL
Biomass can be used in solid or liquid forms. The solid forms of biomass include direct burning of biomass which is most common in rural India as well as burning of cow dung for dung cakes which are also burnt directly or mixed with coal to make round balls of dung and coal powder.
Biofuels in their liquid form, can be classified as follows:
Unmodified vegetable oils
Modified vegetable oils
Pure vegetable oils, especially when refined and deslimed, can be used in prechamber, indirect-injected engines such as the Deutz model and in swirl-chamber diesel engines such as the Ellsbett diesel model. They are also usable when mixed with diesel fuels.
Pure vegetable oil, however, cannot be used in direct-injection diesel engines, such as those regularly used in standard tractors, since engine cooking occurs after several hours of use. All engine types allow additions of vegetable oils mixed with fuels in reduced and small proportions, but residues and cooking negatively affect short-term engine performance.
Some vegetable oils also find application as lubricants and as hydraulic oils. In addition, they can be used in saw machines. In general terms, it is possible to substitute mineral oils for vegetable oils provided that appropriate additives are included. Plant Sources for vegetable oils. Vegetable oil can be obtained from more than 300 different plant species. Oil is contained mainly in fruits and seeds, yet still other origins exist.
The highest oil yields can be obtained from tree crops, such as palms, coconuts, and olives, Jatropha Pongamia, Mahua, Salvadora, but there are a number of field crops containing oils. Climatic and soil conditions, oil content, yields and the feasibility of farm operations, however, limit the potential use of vegetable oils to a reduced number of crops.
From my presentation at 14th European Biomass Conference, 17-21 October 2005, Paris, France