The energy crisis has been an important issue in the recent decades as the continuous demand for the fossil fuels is on the rise. According to the U.S. Energy Information Administration (EIA), the consumption of gasoline in the United States in 2014 was about 3.26 billion barrels(42 U.S.gallons is equal to one barrel). Since fossil fuels are limited, people tend to find alternative fuels as a substitute.
Biofuels from agricultural waste such as wheat straws, corn stover and wood waste have some appealing advantages. For instance, biofuels are from renewable non-food sources which would not cause a food crisis problem in corn or soybeans, and it may reduce air pollution as these wastes absorb CO2 during their processing. Furthermore, utilizing such agricultural waste would save the cost of waste treatment and create huge potential values.
The key technology of making transport fuels from agricultural wastes is fermentation, the same process used to brew beer. The waste contains a large amount of cellulose and hemicellulose which can be broken down into sugars and then fermented into alcohols, usually called bioethanol. The produced bioethanol can be incorporated into gasoline or used only by itself as transport fuels.
The commercialization of this technology has developed all over the world. The U.S. Energy Independence and Security Act in 2007 announced an expectation of producing biofuels at a quantity of 36 billion US gallons per year by 2022. The DuPont Bioethanol Facility in Nevada,USA, expected to be completed in 2015, has the capacity to produce 30 million gallons of ethanol per year from corn stover alone. The Spanish company, Abengoa Bioenergy, currently has seven plants in the U.S. to produce bioethanol from mixed agricultural wastes including non-feed energy crops and wood waste with a maximum capacity of 90 million gallons per year and a minimum of 25 million gallons per year.
Bioethanol has been used as transport fuels in Brazil, where the first car fully fueled by bioethanol was invented and commercialized. Up to now, plenty of car manufacturers have developed commercially available bioethanol vehicles. Additionally, in Europe and America, the petrol/ethanol blend fuels like E5 or E85 are becoming a common option at gas stations. E5 or E85 means ethanol is blended into the gasoline with a volume of 5% or 85% respectively. The E85 filling stations and infrastructures are widely built and operated, especially around the American Corn Belt area.
Sources:
1. U.S. Energy Information Administration. How much gasoline does the United States
consume? http://www.eia.gov/tools/faqs/faq.cfm?id=23&t=10
2. Energy Independence and Security Act of 2007. http://www.gpo.gov/fdsys/pkg/BILLS-
110hr6enr/pdf/BILLS-110hr6enr.pdf
3. DuPont Nevada Site Cellulosic Ethanol Facility. http://biofuels.dupont.com/cellulosic-
ethanol/nevada-site-ce-facility/
4. Abengoa Bioenergy, S.A.
http://www.abengoabioenergy.com/web/en/acerca_de/oficinas_e_instalaciones/bioetanol/eeuu/
5. Bioethanol Production and Use
http://www.erec.org/fileadmin/erec_docs/Projcet_Documents/RESTMAC/Brochure5_Bioethanol
_low_res.pdf
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