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Renewable Energy -Ethanol Effects on Agriculture As the world switches from fossil fuels to ethanol, the prices for food feedstocks will increase. Agriculture is uniquely positioned among the current renewable energy sources, to be a source of energy feedstock that can contribute to the production of both power (electricity) and transportation fuels (ethanol and biodiesel). |
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One result of increased use of ethanol is the increasing demand for feedstocks. Large-scale production of agricultural alcohol may require substantial amounts of cultivable land with fertile soils and water. Clearance of new land often involves burning which can result in a very large emission of carbon dioxide. This may lead to environmental damage such as deforestation or decline of soil fertility due to reduction of organic matter. |
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FACT: Ethanol is a renewable fuel
produced from plants, unlike petroleum-based fossil fuels that have
a limited supply and are the major contributor of carbon dioxide
emissions, a greenhouse gas. FACT: Ethanol has a positive energy balance Graphic Source: FRA (Renewable Fuels Association) ĦĦ |
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Value-added Process of Fuel Ethanol The production process of fuel ethanol is not only a conversion process of grain but also the value-added production process of high quality protein. Only the starch in the grain will be consumed in the production process of fuel ethanol. And in this process, protein and other nutrients are concentrated. The difficultly-utilized protein will be converted into high-quality yeast protein in the process. In other words, the production process of fuel ethanol is also the production process of high-quality protein feed, that is, the value optimization process of feed protein resources. |
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For example, the production of one ton of ethanol consumes three tons of corn and will produce one ton of feed protein DDGS (soluble and insoluble distillers dried grains in the skies ). DDGS feed is recognized worldwide as the high-quality protein feed which enriches 30% protein and other amino acids, vitamins and minerals. That is to say that the protein feed is optimized after the yeast digestion, absorption and metabolism in alcohol fermentation where some common protein changes into high-quality yeast protein. Therefore the absorption is greatly improved and the value of the feed in greatly upgraded. This is one of the most important factors of comprehensive utilization and mass production of fuel ethanol. Take China for example. China recently consumes 50 million ton/year of gasoline. So 5 million ton/year fuel ethanol is needed if E10 will be produced. Thus 15 million ton/year of grain (low-quality feed grain, namely non-food grain) will be consumed. Comparing with the value of 15 million ton/year feed grain, the value will be greatly increased when the same amount of feed are used to produce 5 million t/year fuel ethanol together with 5 million ton DDGS feeds. |
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Early ethanol plants were energy intensive, raising concerns as to whether the transportation fuel being produced was worth the energy going into making it. But the efficiency of corn ethanol production has increased over the last ten years and technical advancements have improved the net energy value of corn ethanol. Today, producing ethanol from corn using domestic supplies of coal and natural gas achieves a net gain in the form of energy and helps displace the need for foreign oil. Besides improving energy security, ethanol fuel technologies offer opportunities for economic development in the struggling rural communities. For every unit of petroleum energy consumed in corn ethanol production, more than six units of fuel energy are produced. Some critics to question the efficiency of ethanol, claiming ethanol has a Ħ°net negativeĦħ energy balance. Energy consumption is dependent on the type of feedstock, the production process used, and the level of technology employed. The potential environmental benefits of ethanol production are directly related to its net energy balance. If energy consumed in the production of ethanol is generated through the use of "dirty" fuels such as coal, the overall environmental impact is less positive. The net energy gain and environmental benefits of ethanol blended fuel are comprimised when "dirty" fuels are used to power any of the various stages of the production process. |
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Concerns Air quality can be an issue when the carbon dioxide and other odour causing emissions produced during the fermentation process are not recaptured or cleaned before being exhausted in the production process of ethanol. The source of an ethanol plant's power, as well as the type of production process, will affect the level of greenhouse gas (GHG) emissions. Natural gas will be the primary energy source for ethanol plants. However, if electricity is produced from coal fired power plants, this will create more atmospheric pollution than a plant capable of integrated power co-generation. Some other direct environmental issues created by ethanol production from grain are water issues (water supply and water quality), and energy consumption issue. When an ethanol plant is operated in conjunction with a feedlot, air quality and contamination of groundwater can become a significant issue. Manure spreading may also cause soil contamination in the ethanol production linked to intensive livestock operations. |
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