Biofuel is biodegradable fuel derived from biomass — plant, algae or animal waste. Since it can be readily replenished, biofuel is a renewable clean source of energy in contrast to fossil fuels. Biofuels are also environment-friendly since they do not emit carbon monoxide and sulphur oxide into the atmosphere like coal and petrol.
The focus today is on liquid biofuels. There are two kinds — ethanol and biodiesel. The latter is derived by fermenting corn, sugarcane, or plant materials. The US and Brazil are among the leading producers of ethanol which is blended with petrol to produce greener fuel. Biodiesel is produced from vegetable oils, animal fat and waste cooking oil. The main sources of biodiesel are palm, soyabean and rapeseed.
The other biofuel is compressed biogas (CBG) made through the digestion of biomass minus the presence of oxygen. CBG can be made from agricultural residue, cattle dung, sugarcane press mud, municipal solid waste, sewage treatment plant waste. Presently India produces 1151 MT of CBG with a projected increase to 1750 MT by 2025.
There is downside
While biofuels are greener than fossil fuels, there is a downside. Critics point out that diverting land for biofuels can cut into food supplies when demand for food is expected to rise by 70 per cent by 2050. Land use has become a controversial issue with some experts pointing out that food prices could spike if agricultural land is diverted to feeding the biofuel industry.
As for biogas, it is renewable because humans and animals will keep producing waste. But critics point out that as a society we should discourage generating that leaves landfills and waste dumps overflowing. Alternative sources of clean energy like solar, wind and tidal energy are better alternatives.