The ethanol industry in Thailand has been active since 1961 as one of the Royal Project of His Majesty the King. Later, as an oil-importing country, Thailand has lost economic growth opportunity and energy security due to limited oil supply and price fluctuation. The seek for alternative energy for liquid fuel uses for transportation sector has been developed as a part of National Energy Policy and ethanol was then upgraded as national policy in 1995, initially in order to replace a toxic Octane Booster, i. e. Methyl tert-butyl ether (MTBE) in gasoline. By that time, the consumption rate of gasoline was 20 million liters per day which required 10% Octane Booster or 2 million liter per day; this formula is equivalent to Gasohol E10 (for octane 91 and 95), a blend of unleaded gasoline with 10% v/v anhydrous ethanol. With a rising concern of Global Warming and Clean Development Mechanism (CDM), gasohol containing higher ethanol components has been currently developed; E20 & E85. Presently, there are 47 factories legally licensed to produce biofuel ethanol with a total capacity of 12.295 million liters/day or 3,688.5 million liters per annum (at 300 working days). Two feedstocks, namely sugar cane molasses and cassava are their primary raw materials. A total of 40 factories use only a single feedstock; 14 factories using molasses with a total production capacity of 2.485 million liters/day, 25 factories using cassava with a total production capacity of 8.590 million liters/ day and 1 factory using sugar cane with a total production capacity of 0.2 million liters/ day. A multi-feedstock process using both molasses and cassava is, however, preferred in some factories (7 factories with a total production capacity of 1.020 million liters/day) to avoid feedstock shortage (Department of Alternative Energy Development and Efficiency, DEDE, 2009). A complication of Thai bioethanol industry is generated due to the fact that there are two feedstock types being used in other industries and also other alternative energy for transportation, i. e. LPG (Liquefied petroleum gas) and CNG (Compressed natural gas), being promoted by the government.