Published Date
Applied Energy November 2009, Vol.86:S170–S177,doi:10.1016/j.apenergy.2009.05.010 Bio-fuels in Asia Author
Thapat Silalertruksa a,b
Shabbir H. Gheewala a,,
Masayuki Sagisaka b
aThe Joint Graduate School of Energy and Environment, King Mongkut’s University of Technology Thonburi, 126 Prachauthit Road, Bangkok 10140, Thailand
bMaterial and Energy Sustainability Assessment Group, Institute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology (AIST), Onogawa 16-1, Tsukuba, Ibaraki 305-8569, Japan
Received 15 January 2009. Revised 29 April 2009. Accepted 6 May 2009. Available online 31 May 2009. This article is sponsored by the Asian Development Bank as part of the Supplement ‘‘Biofuels in Asia”.
Abstract The growing demand for biofuels has led to an increased demand for feedstocks which in turn is anticipated to induce changes in the cropping systems or land requirement for agriculture use. This study used consequential life cycle assessment (LCA) to evaluate the environmental consequences of possible (future) changes in agricultural production systems and determine their effects on land use change (LUC) and greenhouse gas (GHG) implications when cassava demand in Thailand increases. Six different cropping systems to increase cassava production including converting unoccupied land to cropland, yield improvement, displacement of area currently under sugarcane cultivation and the other potential changes in cropping systems in Viet Nam and Australia are modeled and assessed. The comparative results show that LUC is an important factor in overall GHG emissions of the first generation biofuels especially change in soil carbon stock contributing about 58–60% of the net GHG emissions. Increased cassava production by expanding cultivation area has a significantly larger effect on GHG emissions than increased productivity. The analysis shows that increasing productivity of both sugarcane and cassava are important ways to maximize benefits in using of certain area of Thailand to serve both the food and fuel industries. Keywords
Published Date
Journal of Cleaner Production May 2009, Vol.17(8):772–779,doi:10.1016/j.jclepro.2008.12.001 Author
Ana M. Contreras a
Elena Rosa a
Maylier Pérez a
Herman Van Langenhove b
Jo Dewulf b,,
aFaculty of Chemistry and Pharmacy, Central University of Las Villas, Carretera a Camajuani km 5½, C.P. 54830 Santa Clara, Villa Clara, Cuba
bResearch Group ENVOC, Faculty of Bioscience Engineering, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium
Received 1 April 2008. Revised 28 November 2008. Accepted 1 December 2008. Available online 25 December 2008.
Abstract Cane sugar production by-products can be considered either as waste, affecting the environment, or as a resource when an appropriate valorization technology is implemented. This study is made with the objective of identifying and quantifying the aspects which have the largest environmental impact of four alternatives for using by-products and wastes from the cane sugar process and suggest improvements in the systems. For this analysis a cane sugar mill was chosen in Cuba and four alternatives were designed for the by-product valorization. The first alternative represents the conventional sugar production; its main characteristics are the use of synthetic fertilizers, pesticides, the bagasse combustion and the usage of molasses and agricultural wastes as animal food. Other wastes constitute emissions to the environment. Alternatives II, III and IV incorporate more use of by-products and wastes. Alternative II considers the use of wastewater, filter cake and ashes for the substitution of synthetic fertilizers. In Alternative III, the filter cake and wastewater are used for biogas production and Alternative IV integrates alcohol and biogas production into the sugar production process. The assessment is done by means of Life Cycle Assessment, according to the ISO 14040 series by using the SimaPro 6.0 LCA software, Ecoinvent database and the Eco-indicator 99 methodology. As a functional unit the daily sugar production of the mill was defined (216 t/d). The sugar was selected as main product and all the by-products were assumed to substitute other products on the market, avoided products. For the four alternatives, the agricultural stage shows the greatest impact due to land use, fuel and agrochemicals consumption. In the industrial stage, the electricity cogeneration with bagasse has the highest impact as to respiratory effects due to the emission of tiny particle material into the atmosphere. The major difference between the alternatives is found in the resource impact category. The advantage of producing alcohol, biogas, animal food and fertilizers from the by-products is made obvious through the comparative study for resource savings. Keywords
Published Date
Applied Energy August 2008, Vol.85(8):722–734,doi:10.1016/j.apenergy.2008.02.002 Author
Thu Lan T. Nguyen
Shabbir H. Gheewala,
Savitri Garivait
The Joint Graduate School of Energy and Environment, King Mongkut’s University of Technology Thonburi, Bangkok, Thailand
Received 24 September 2007. Revised 28 December 2007. Accepted 1 February 2008. Available online 18 March 2008.
Abstract An analysis of energy performance and supply potential was performed to evaluate molasses utilization for fuel ethanol in Thailand. The Thai government recently has set up a production target of 1.925 million litres a day of sugar-based ethanol. The molasses-based ethanol (MoE) system involves three main segments: sugar cane cultivation, molasses generation, and ethanol conversion. Negative net energy value found for MoE is a consequence of not utilizing system co-products (e.g. stillage and cane trash) for energy. Taking into account only fossil fuel or petroleum inputs in the production cycle, the energy analysis provides results in favour of ethanol. A positive net energy of 5.95 MJ/L which corresponds to 39% energy gain shows that MoE is efficient as far as its potential to replace fossil fuels is concerned. Another encouraging result is that each MJ of petroleum inputs can produce 6.12 MJ of ethanol fuel. Regarding supply potential, if only the surplus molasses is utilized for ethanol, a shift of 8–10% sugar cane produce to fuel ethanol from its current use in sugar industry could be a probable solution. Keywords
Published Date
Journal of Cleaner Production March 2010, Vol.18(5):412–418,doi:10.1016/j.jclepro.2009.12.012 Author
Thu Lan T. Nguyen a,b
Shabbir H. Gheewala b,,
Masayuki Sagisaka c
aDepartment of Agroecology, Aarhus University, Denmark
bThe Joint Graduate School of Energy and Environment, King Mongkut's University of Technology Thonburi, Bangkok 10140, Thailand
cInstitute of Science for Safety and Sustainability, National Institute of Advanced Industrial Science and Technology, Tsukuba, Japan
Received 13 October 2008. Revised 2 September 2009. Accepted 18 December 2009. Available online 4 January 2010.
Abstract One of the major justifications for bio-energy systems is their low greenhouse gas (GHG) emissions compared to fossil-energy ones. Transforming a sugar mill into a bio-energy plant would contribute to climate change mitigation via the extraction of renewable electricity and ethanol. This study takes the case of the sugar industry in Thailand and identifies scenario options that offer GHG reduction benefits. Improving efficiency in electricity generation from sugar cane residues e.g. excess bagasse and cane trash is such a beneficial option. Furthermore, extracting ethanol in a so-called bio-refinery, where the co-product stillage is utilized for energy, tends to magnify the potential benefit. The largest savings potential achieved with extracting ethanol from surplus sugar versus current practice in the sugar industry in Thailand amounts to 14 million tonnes CO2e a year. This cannot be realized in practice until the carbon debt from land conversion is repaid, which takes 4.5–7 years, assuming that the land converted is grassland. Keywords
