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Biofuels are often presented as an environmentally friendly alternative to fossil fuels, however, empirical analysis that is widely reported in the literature shows that biofuel production can have negative environmental and social impacts. The potential for these negative impacts can be avoided through careful planning of biofuel feedstock production and processing. This paper reports on research in Khon Kaen province in north-eastern Thailand into this issue. The report focuses on how green technologies and practices can be introduced into ethanol production to reduce its environmental footprint. The emissions from ethanol production were estimated applying the life cycle greenhouse gas emission analysis from land use change, cultivation of cassava and sugarcane, ethanol processing, and transportation. The farming data in the study sites was used to estimate the emissions from crop cultivations and transportation of cassava and sugarcane to the ethanol plants. Emissions from ethanol production processing were measured based on the production data from a combined sugar milling and molasses ethanol factory, cassava flour and ethanol factory. The results showed that emissions from sugarcane farming (32 g CO2eq/MJ ethanol) had higher than cassava farming (5 g CO2eq/MJ ethanol) due to higher amount of chemical fertilizer used and burning during harvest. The green agricultural technology for sugarcane farming presented that nonburning, drainage management in irrigated area, and reduced use of chemical fertilizer but increased use of green compost would reduce emissions per year at 17 g CO2eq/MJ ethanol. The ethanol production from cassava had high emission from burning of coal in the internal boilers of ethanol production processing (56 g CO2eq/MJ ethanol). The electricity and biogas as by-products of waste utilization would reduce emissions from substitution of coal and convention electricity per year at 14 -26 g CO2eq/MJ ethanol. The green technologies and practices demonstrated the potential of GHG emissions reduction and improve the environment.
Key words: GHG emissions, green technology, climate change mitigation