Ethanol
Large imports of foreign crude oil in the 1960s and 1970s stimulated interest in fuel ethanol (Harsch, 1992). In the United States the primary approach taken was the production of gasohol, a blend of ethanol and gasoline. Researchers found that ethanol and its derivative, ethyl tert-butyl ether, work as octane enhancers, which increase the efficiency of gasoline burned in an internal combustion engine. Similar interest in ethanol occurred in Brazil, and, with subsidies from the government, Brazil forged ahead with ethanol production. Until six years, ago nearly 95 percent of the cars produced in that country ran on ethanol. Lately, Brazil has converted to ethanol-gasoline blends for their fuels (Anderson, 1993).
In the United States, ethanol occupies a niche in the transportation fuel market as an oxygenate in urban areas that do not meet the U.S. Environmental Protection Agencys air quality standards for carbon monoxide. Gasoline is blended with an oxygenate fuel such as ethanol or methyl tert-butyl ether (MTBE) to increase the combustion efficiency of gasoline and decrease carbon monoxide emissions in cold weather. Due to its lower cost in comparison with ethanol, MTBE has been the primary oxygenate used, and its use ranges from 63 to 81 percent of the total demand for oxygenates (EIA, 1997). Total estimated U.S. production of MTBE in 1995 was 8 billion kilograms; estimated ethanol production for 1994 was 4.3 billion kilograms (Committee on Environment and Natural Resources, 1997).
An interagency panel assessed the air quality, groundwater and drinking water quality, fuel economy and engine performance, and the potential health effects of MTBE and other oxygenates (Committee on Environment and Natural Resources, 1997). In its review of the draft federal report, the National Research Council concluded that the cold-weather air pollution effects of oxygenated fuels were unclear. While data on the occurrence of MTBE in groundwater and drinking water are scarce, MTBE has been detected in groundwater (Squillace et al., 1996), stormwater (Delzer et al., 1996), and drinking water (Committee on Environment and Natural Resources, 1997). Because MTBE is very soluble in water, is not readily absorbed by soil and aquifer materials, and generally resists degradation in groundwater, the interagency group recommended that there be an effort to obtain more complete monitoring data, behavior and fate studies, and aquatic toxicity tests for wildlife and to establish, if warranted, a federal water quality criterion.
Specific well-targeted research will be needed to answer questions about potential tradeoffs in using these chemicals as additives to gasoline (NRC, 1996). Demand for starch-based ethanol is influenced by the commodity market price for corn. During the 1995 to 1996 marketing year, high demand for corn grain drove up corn prices to record levels, leading to high input costs and a downturn in ethanol fuel production. Many ethanol producers opted to suspend ethanol production and do maintenance on their manufacturing facilities. Other producers diverted ethanol fuel production to the alcoholic beverage market. The USDA expects that producers will need to reestablish long-term contracts with blenders to regain market share lost due to corn markets experiencing a period of high input pricing in 1995 to 1996 (ERS, 1997).
In the long term, large-scale production of fuel ethanol from lignocellulose materials could become technically feasible and economically favorable. A key will be demonstrating that recent and anticipated technical innovations work at larger scales with representative raw materials. The production cost of ethanol from woody biomass must drop significantly if it is to penetrate a much larger fraction of the transportation fuel market. This change will occur only if economical lignocellulose conversion technologies are developed—a long-sought achievement. Use of these alternative feedstocks with new conversion processes may reduce production costs sufficiently to allow access to the commodity fuel market, even without subsidies or tax incentives. Lignocellulose-ethanol processing may be one approach toward reducing the costs of ethanol production (Bergeron and Hinman 1989).
There is a multi-national project on-going to investigate the utilization of ethanol. For more information, please refer to the BEST project. In the United States, the National Ethanol Vehicle Coalition is the nations primary advocate for blended fuels that use 85 percent ethanol (E85).
Encyclopedia ID: p1190
