Energy efficiency and potentials of cassava fuel ethanol in Guangxi region of China.

The Guangxi Zhuang autonomous region has plentiful cassava resources, which is an ideal feedstock for fuel ethanol production. The Guangxi government intends to promote cassava fuel ethanol as a substitute for gasoline. The purpose of this study was to quantify the energy efficiency and potentials of a cassava fuel ethanol project in the Guangxi region based on a 100 thousand ton fuel ethanol demonstration plant at Qinzhou of Guangxi. The net energy value (NEV) and net renewable energy value (NREV) are presented to assess the energy and renewable energy efficiency of the cassava fuel ethanol system during its life cycle. The cassava fuel ethanol system was divided into five subsystems including the cassava plantation/treatment, ethanol conversion, denaturing, refueling and transportation. All the energy and energy related materials inputs to each subsystem were estimated at the primary energy level. The total energy inputs were allocated between the fuel ethanol and its coproducts with market value and replacement value methods. Available lands for a cassava plantation were investigated and estimated. The results showed that the cassava fuel ethanol system was energy and renewable energy efficient as indicated by positive NEV and NREV values that were 7.475 MJ/L and 7.881 MJ/L, respectively. Cassava fuel ethanol production helps to convert the non-liquid fuel into fuel ethanol that can be used for transportation. Through fuel ethanol production, one Joule of petroleum fuel, plus other forms of energy inputs such as coal, can produce 9.8 J of fuel ethanol. Cassava fuel ethanol can substitute for gasoline and reduce oil imports. With the cassava output in 2003, it can substitute for 166.107 million liters of gasoline. With the cassava output potential, it can substitute for 618.162 million liters of gasoline. Cassava fuel ethanol is more energy efficient than gasoline, diesel fuel and corn fuel ethanol but less efficient than biodiesel.

[1]  John Sheehan,et al.  Life Cycle Inventory of Biodiesel and Petroleum Diesel for Use in an Urban Bus , 1998 .

[2]  Maureen Lorenzetti.  Clean fuels specifications part of shifting US political landscape , 2002 .

[3]  Michael Wang,et al.  Effects of Fuel Ethanol Use on Fuel-Cycle Energy and Greenhouse Gas Emissions , 1999 .

[4]  H. D. Tindall,et al.  Fruit and Vegetable Production in Africa , 1987 .

[5]  David Pimentel,et al.  Ethanol Fuels: Energy Balance, Economics, and Environmental Impacts Are Negative , 2003 .

[6]  C. Hopkinson,et al.  Net Energy Analysis of Alcohol Production from Sugarcane , 1980, Science.

[7]  Gengqiang Pu,et al.  Life cycle economic analysis of fuel ethanol derived from cassava in southwest China , 2003 .

[8]  Handan Akcaoz,et al.  Energy input¿output analysis in Turkish agriculture , 2004 .

[9]  D. L. Morris.  How Much Energy Does It Take to Make a Gallon of Ethanol , 1995 .

[10]  中華人民共和国国家統計局.  China statistical yearbook , 1988 .

[11]  Hans-Jürgen Dr. Klüppel,et al.  The Revision of ISO Standards 14040-3 - ISO 14040: Environmental management – Life cycle assessment – Principles and framework - ISO 14044: Environmental management – Life cycle assessment – Requirements and guidelines , 2005 .

[12]  Michael Q. Wang,et al.  The Energy Balance of Corn Ethanol: An Update , 2002 .

[13]  John Sheehan,et al.  Life cycle inventory of biodiesel and petroleum diesel for use in an urban bus. Final report , 1998 .

[14]  Matt Chwalowski,et al.  Critical questions about the full fuel cycle analysis , 1996 .