Biofuels, including alcohol, vegetable oils, biogas and fuelwood, are fuels derived from living biomass. They have always been used as a source of energy. The energy crisis of the 1970’s led countries to seek ways to improve their energy security by decreasing their dependence on traditional fossil fuels and diversifying their energy supplies. Currently, there are two major liquid biofuels that can be used in the transportation industry: bioethanol which is produced out of plant starch and sugar, and biodiesel made out of vegetables or grain oil. While liquid biofuel production has never really been significant due to the low price of oil, the role of biomass as a fossil fuel energy substitute has regained a lot of interest in the past decade due to (i) instability in petroleum producing countries, (ii) the rising cost of fossil fuel from less than 20 US$ per barrel in 1995 (2006 dollars) to more than 60 US$ in 2006 (WTRG Economics, 2006) and (iii) the adoption and entry into force of the Kyoto Protocol that requires countries to reduce their greenhouse gas emissions.
The scale of the industry and the number of countries involved in the production and use of liquid biofuel are expanding at an accelerated pace (Worldwatch Institute, 2006). While global oil production increased by 7% between 2000 and 2005, bioethanol production expanded nearly threefold and biodiesel production increased more than threefold (Brown, 2006; Worldwatch Institute, 2006). In 2005, the production of liquid biofuels represented nearly 2% of the global gasoline use (Brown, 2006). Bioethanol accounted for 90% of the global biofuel production, and biodiesel made up the remaining 10% (Worldwatch Institute, 2006).