Bioethanol as a Transportation Fuel
Ethanol and ethanol blends have a long history as alternative transportation fuels. As far back as 1826, Samuel Morey used an ethanol turpentine mixture as the fuel in his experiments with internal combustion engines. In 1860, Nicholas Otto began experimenting with ethanol-powered internal combustion engines. In the United States, bioethanol and ethanol turpentine blends were popular as fuels long before the development of petroleum crude oil-based gasoline as a fuel. Oil was found in 1859 in Pennsylvania, and later, the discovery of a ready supply of oil in Texas and other parts of the United States coupled with unfavorable taxation on ethanol-based fuels made gasoline and kerosene more popular fuels. Early US automobile engines were developed to run on pure ethanol or ethanol blends. In 1896, Henry Ford designed his first automobile, the "Quadricyle" to run on pure ethanol . The famous Ford Model T, generally regarded as the earliest affordable automobile, was first manufactured in 1908 and was capable of running on gasoline, ethanol, or a gasoline-ethanol mixture .
Gasoline-ethanol mixtures have been used in Germany and France as early as 1894 by the then developing industry of internal combustion engines . Brazil has utilized sugarcane-derived bioethanol as a fuel since 1925. By that time, the production of bioethanol was 70 times bigger than the production and consumption of gasoline . In the United States bioethanol was widely used as a main transportation fuel until the early 1900s. However, with the discovery of new oil wells, ethanol became less competitive with gasoline as it became more expensive to produce than petroleum - based fuel, especially after World War II.
In the 1970s, the energy crisis was a turning point in the renewed interest in ethanol. During this period major industrialized countries of the world, particularly the United States, Canada, Western Europe, and Japan, were heavily affected; they faced substantial gasoline shortages and perceived and real elevated prices. The crisis led to stagnant economic growth in many countries as oil prices climbed. Another factor that contributed to the renewed interest in ethanol was the discovery that methyl tertiary butyl ether (MTBE), which was added to gasoline to increase its octane rating and to help prevent engine knocking, was contaminating ground water . During this time ethanol was identified as a less toxic favorable substituent for MTBE as an octane number enhancer, and as a result of this discovery, a slow but steady growth in the usage of ethanol was seen after the 1970s. Later, this movement was further supported due to mandates in the Clean Air Act Amendments of 1992 to reduce carbon monoxide emission by the addition of oxygenates. As a consequence of this amendment, use of ethanol as an oxygenate additive became widespread in the United States, and MTBE in gasoline was banned in almost 20 states by 2006. MTBE suppliers were concerned about potential litigation due to a 2005 court decision denying legal protection for its use. Then, MTBE's fall from grace opened a new market for ethanol as a primary substitute as an octane number enhancer .
However, the steep growth in ethanol consumption in the United States after 2005 as a transportation fuel was driven by a string of federal legislation aimed at reducing oil consumption and boosting energy security. The Energy Policy Act of 2005 required the use of 7.5 billion US gallons of renewable fuel by 2012, and the Energy Independence and Security Act of 2007 raised the standard to 36 billion US gallons of annual renewable fuel use by 2022 . Of this requirement, 16 billion US gallons had to be advanced biofuels, defined as renewable fuels that reduce greenhouse gas emissions by at least 50% .