Greenhouse Gas Emission Reduction Assessment of Bioethanol, Biodiesel, Biogas and Biomass Direct Combustion

Many countries have recently focused considerable attention on developing viable renewable bioenergy as leading alternatives to fossil energy in order to address the issue of global warming. In this paper, the greenhouse gas emission reduction assessment of bioenergy was carried out. The calorific values of the same bioenergy were similar while the net energy ratio (NER) and the greenhouse gas emission net reduction (GGENR) were related to the feedstocks. Because of the lower input energy, the GGENR of corn stover bioethanol (52603kg CO2/TJ) was higher than corn bioethanol (10660kg CO2/TJ). Moreover, both NER and GGENR of sugarcane bioethanol achieved the highest value among the three bioethanol due to the specific climate and geographic conditions in Brazil, 9.3 and 61418kg CO2/TJ respectively. The NERs of biodiesel produced from soybean and microalgae were close, 1.93 and 1.34 respectively. However, the GGENR of soybean biodiesel was 86% higher than microalgae. As for biogas and biomass direct combustion, the GGENRs were 56100kg CO2/TJ and 98300kg CO2/TJ, respectively. (C) 2011 Published by American Applied Sciences Research Institute