Green Fuels for Internal Combustion Engines

Another environmental competitor to the hybrid electric vehicle is the internal combustion engine fuelled with bio-ethanol. Since this ethanol is produced 

Bio-diesel, an alternative biofuel, is made from a vegetable oil that is extracted from the seeds of plants such as canola (rape plant), cotton, soybean and sunflower. This oil, which is used mostly in the manufacture of margarine, is reacted chemically with methanol to produce a methyl ester that can substitute satisfactorily for diesel fuel. Glycerol is produced as a by-product. Generally, up to 20 vol.% of bio-diesel is mixed with conventional diesel. Again, there is the problem of unfavourable economics. Bio-diesel is not yet fully cost competitive and the overall energetics of production, transport and consumption require careful evaluation. 

Biofuels are claimed to offer many different benefits at the national level. These include (i) reduced dependence on the diminishing reserves of petroleum (ii) greater energy security (iii) a smaller bill for oil imports (iv) less pollutants released to the atmosphere (v) the introduction of major industries to produce bio-ethanol and bio-diesel and (vi) a new market for farmers. On the debit side, one has to consider the additional fossil fuel that will be expended (and carbon dioxide released) in the provision of extensive and sustainable supplies of these sources of energy. There is also the competition for land to produce food and the possible impoverishment of the soil. Overall, it is probable that in the short term biofuels will assume an increasing, but still modest, role in transportation. 

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