Handbook of Cellulosic Ethanol
Biofuels
Biomass-derived fuels or biofuels are an important contributor in the modern renewables slice of the energy source distribution pie chart shown in Figure 1.2. The use of biogas in heating houses, biogas-derived syngas in electricity generation and transport biofuels are some of the major applications in this type of sustainable energy. Biofuels are produced from bio-based materials through various paths such as biochemical [5, 6], and thermochemical methods [7, 8]. In general the use of unprocessed biomass forms like firewood for heating or cooking purposes are not included in this group. Chemically, many forms of biofuels contain oxygen as one of the elements, whereas petroleum fuels are hydrocarbons free of oxygen. Another important difference is the sulfur level; all biofuels are very low in sulfur in comparison to petroleum fuels and many have low nitrogen levels as well.
