Various types of biofuels and feedstocks are considered and discussed in terms of their environmental and economic feasibilities. Biofuel is gaining the centre stage as human activities keep rising and the consequent increase in the discharge of lethal emissions is also a subject of concern. The need to cut down greenhouse gas emissions (i.e. CO2, N2O, CO, NO, SO2) is imperative to preserve our natural biodiversity. Biodiesel and bioethanol are the most common, viable alternatives and infinite green fuels that can be used in internal combustion engine. Biodiesel (commonly from waste cooking oil, nonedible vegetable oil, animal fat and tallow) and bioethanol (usually from forestry waste, Lignocellulosic biomass, starchy and sugary vegetable sources, and agricultural residues) are synthesized from straight vegetable feedstocks to bring their characters close to that of the fossil diesel and gasoline. The candidates as green fuels have the potential to significantly reduce the greenhouse gas emissions by as much as 30% from their combustion in internal combustion engine. The various possible methods used for their productions determine the fuel sensitivity to the environment and the energy balance. In general, the energy balances are positive for both fuel substitutes.
Part of the book: Anaerobic Digestion