Considering energy security and greenhouse gas emission, many governments are developing bio-liquid fuel industries. The Chinese Government advocates the development of a fuel ethanol industry with non-food crops such as cassava. However, scientists debate the carbon emission of these bio-liquid fuels. The focuses are the influence of soil carbon pool destruction and by-product utilization. This study built a carbon balance analysis model, and assessed carbon emission of cassava fuel ethanol across its life cycle. The results show that the carbon emission of cassava fuel ethanol per kilogram in its life cycle was 0.457 kg under new technical conditions and 0.647 kg under old technical conditions. Carbon emission mainly came from the use of nitrogen fertilizer (9% of total emissions), the destruction of the soil carbon pool (29%) and fossil energy inputs (50%). Taking gasoline as a reference, the carbon emission of cassava fuel ethanol was 90% of that of gasoline. This percentage would drop to 64% if soil carbon pool destruction was avoided. Therefore, in order to promote the development of cassava fuel ethanol in China, farms should apply fertilizer properly, grow cassava on marginal land, and not alter land use patterns of woodland, grassland and other environments. In addition, we should exploit efficient fuel ethanol conversion technologies and strengthen the use of by-products.
YANG Hailong, LV Yao, FENG Zhiming
. Carbon Balance of Cassava-based Ethanol Fuel in China[J]. Journal of Resources and Ecology, 2012
, 3(1)
: 55
-63
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DOI: 10.5814/j.issn.1674-764x.2012.01.009
Adler P, Del S J and Parton W J. 2007.Net greenhouse gas flux of bioenergy cropping systems using DAYCENT. Ecology Application, 13(8):345-352.
Atjay G L, Ketner P and Duvigneaud P. 1979.Terrestrial primary production and phytomass. In: Bolin B, Degens E T, Kempe S, Ketner P(eds). The Global Carbon Cycle. Chichester, UK: John Wiley and Sons. 129-181.
Batjes N H. 1996.Total carbon and nitrogen in the soil of the world. Soil Sciences, 47: 151-163.
China Renewable Energy Development Strategy Research Group (CREDSRG). 2008. China renewable energy development strategy study series book-volume of biomass. Beijing: China Electric Power Press.
Dai D, Liu R H and Pu G Q. 2005. Evaluation of energy production efficiency of biomass based fuel ethanol program. Transactions of the CSAE, 21(11): 121-123. (in Chinese)
Dong D D, Zhao D Q, Liao C P, et al. 2008. Energy consumption analysis in life cycle of cassava fuel ethanol production and the advantages of the new technology in energy consumption. Transactions of the CSAE, 24(7): 160-164. (in Chinese)
IEA. 2011.World energy outlook 2011. IEA.
Elsayed M, Matthews R and Mortimer N. 2003. Carbon and energy balances for a range of biofuel options. Sheffield Hallam University.
FAO. 2008. Food and agricultural situation—bioenergy: prospect, risk and chance. Rome.
Farrell A E, Plevin R J, Turner B T. et al. 2006. Ethanol can contribute to energy and environmental goals. Science, 311(5760): 506-508.
Hao H Y, Deng L K and Du J B. 2009. Discussion on energy comprehensive utilization pattern in cassava fuel ethanol production process. Cereal and Food Industry, 16(4): 30-33. (in Chinese)
Hu Z Y, Dai D and Zhang C. 2003. Life cycle assessment on mixed fuel of cassava-based ethanol and gasoline. Journal of Internal Combustion Engine, 21(5): 341-345. (in Chinese)
Hu Z Y, Dai D, Pu G Q, et al. 2004. Life cycle energy efficiency assessment of cassava-based fuel ethanol . Journal of Shanghai Jiao Tong University, 38(10): 1715-1718. (in Chinese)
Hu Z Y, Pu G Q and Wang C G. 2004. Life cycle assessment on emission of cassava-based ethanol. Automotive Engineering, 26(1): 16-19. (in Chinese)
Hu Z Y, Zhang C and Pu G Q. 2004. Life cycle assessment on energyenvironment and economy of cassava-based ethanol and gasoline mixed fuel. Journal of Internal Combustion Engine, 25(1): 13-16. (in Chinese)
IPCC. 1996. Climate Change 1995: The science of climate change (Report of Working Group 1): New York: Cambridge University Press, 1996, 4.
Joseph F, Jason H, David T, et al. 2008. Land clearing and the biofuel carbon debt. Science, 319 (5867): 1235-1238.
National Bureau of Statistics of China (NBS). 2009. China Statistical Yearbook. Beijing: China Statistics Press.
Ni J B, Wang W B, Tian K, et al. 2007. A Study on soil organic carbon content change of betula alnoides plantation in hot areas of Yunnan Province. Journal of West China Forestry Science, 36(1):57-60. (in Chinese)
Renton R and Dominick V S. 2007. Carbon mitigation by biofuels or by saving and restoring forests? Science, 317: 902.
Revin P B. 2001. Carbon balance of sugarcane bioenergy systems. Biomass and Bioenergy, 20(5): 361-370. Schlamadinger B, Spitzer J and Kohlmaier G H, et al. 1995. Carbon balance of bioenergy from logging residues. Biomass and Bioenergy, 8(4):221- 234.
Searchinger T, Heimlich R, Houghton R A. et al. 2008. Use of U.S. croplands for biofuels increases greenhouse gases through emissions from land use change. Science, 319(5867):1238-1240.
Soil Sciences Academy of Agricultural Chemistry Committee (SSAACC). 1989. Routine analysis methods of soil agricultural chemical. Beijing:Science Press.
Thu L T N, Shabbir H G, Heewala, et al. 2007. Energy balance and GHGabatement cost of cassava utilization for fuel ethanol in Thailand. Energy Policy, 35, 4585-4596.
Tropical Research Institute. 2008. Some biofuels are worse environmentally than fossil fuels. Science Daily, 2008-01-03.
Wei Z Y, Qi Z P and Li K M. 2007. Soil nutrition and countermeasures of cassava plants in Wuming. Journal of Anhui Agricultural. Science, 35(32):10385-10387. (in Chinese)
Wuming Bureau of Statistics (WBS). 2008. Wuming Statistical Yearbook. Wuming: Statistics Press.
Zhang X L, Chang S Y, Ou X M, et al. 2009. A study on resources and technical potential of the development of Chinese bio-liquid fuel. Energy,Environment and Economic Research Institute of Tsinghua University.
Zhang Z J, Zhu B and Xiang H Y. 2010. N2O emission and denitrification of N fertilizer on winter wheat in southwest purple soil. Journal of Agriculture Environmental Science, 29(10):2033-2040. (in Chinese)
Zhang Z S and Yuan X G. 2006. Carbon balance analysis of corn fuel ethanol in life cycle. Environmental Science, 27(4): 616-619.
