53
© The Editor(s) (if applicable) and the Author(s) 2018
K. Takeuchi et al. (eds.), Biofuels and Sustainability, Science for Sustainable
Societies, https://doi.org/10.1007/978-4-431-54895-9_6
Chapter 6
The Effect of Biofuel Production
on Greenhouse Gas Emission Reductions
Keisuke Hanaki and Joana Portugal-Pereira
6.1 Introduction
Fossil fuel consumption is a major cause of climate change. Biofuels can reduce the
consumption of fossil fuels and thus reduce carbon dioxide emissions, because biofuels are carbon neutral. More specifically, the carbon dioxide that is emitted when
a biofuel is burned merely returns to the atmospheric carbon dioxide that was taken
into plants from the atmosphere by photosynthesis. Therefore, biofuels seem to be
a very effective means for reducing these emissions, at least at first sight.
However, the reality is not so simple but controversial (Edwards et al. 2007;
Fargione et al. 2008; Hill et al. 2006; Menichetti and Otto 2009; Searchinger et al.
2008). The production of a biofuel consists of growing an energy crop and using
biomass obtained from the crop as a raw material for making liquid fuel. The production of bioethanol includes processes of fermenting sugarcane, corn, or other
sugar-based feedstock and distilling the contents in a similar manner to distilling
liquor, and the production of biodiesel includes a chemical reaction (transesterification) using vegetable oil as a raw material. Additionally, feedstock is collected in the
farmland to the fuel production plants, and then biofuels are distributed to filling
stations, where they are sold to consumers. These processes inevitably consume
energy.
Moreover, it has been pointed out that greenhouse gases (GHGs) are also generated by the cultivation of energy crops. One of the GHGs, nitrous oxide, is generated when fertilizers are used to raise the yields of energy crops. Furthermore, when
forest land is converted to use for energy crop plantations, the carbon dioxide
absorption of the forests is lost, in addition to which organic matter in the soil breaks
down and generates carbon dioxide. All these issues mean that the production of
K. Hanaki (*) · J. Portugal-Pereira
Department of Urban Engineering, The University of Tokyo,
7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
e-mail: hanaki@iniad.org
© The Editor(s) (if applicable) and the Author(s) 2018
K. Takeuchi et al. (eds.), Biofuels and Sustainability, Science for Sustainable
Societies, https://doi.org/10.1007/978-4-431-54895-9_6
Chapter 6
The Effect of Biofuel Production
on Greenhouse Gas Emission Reductions
Keisuke Hanaki and Joana Portugal-Pereira
6.1 Introduction
Fossil fuel consumption is a major cause of climate change. Biofuels can reduce the
consumption of fossil fuels and thus reduce carbon dioxide emissions, because biofuels are carbon neutral. More specifically, the carbon dioxide that is emitted when
a biofuel is burned merely returns to the atmospheric carbon dioxide that was taken
into plants from the atmosphere by photosynthesis. Therefore, biofuels seem to be
a very effective means for reducing these emissions, at least at first sight.
However, the reality is not so simple but controversial (Edwards et al. 2007;
Fargione et al. 2008; Hill et al. 2006; Menichetti and Otto 2009; Searchinger et al.
2008). The production of a biofuel consists of growing an energy crop and using
biomass obtained from the crop as a raw material for making liquid fuel. The production of bioethanol includes processes of fermenting sugarcane, corn, or other
sugar-based feedstock and distilling the contents in a similar manner to distilling
liquor, and the production of biodiesel includes a chemical reaction (transesterification) using vegetable oil as a raw material. Additionally, feedstock is collected in the
farmland to the fuel production plants, and then biofuels are distributed to filling
stations, where they are sold to consumers. These processes inevitably consume
energy.
Moreover, it has been pointed out that greenhouse gases (GHGs) are also generated by the cultivation of energy crops. One of the GHGs, nitrous oxide, is generated when fertilizers are used to raise the yields of energy crops. Furthermore, when
forest land is converted to use for energy crop plantations, the carbon dioxide
absorption of the forests is lost, in addition to which organic matter in the soil breaks
down and generates carbon dioxide. All these issues mean that the production of
K. Hanaki (*) · J. Portugal-Pereira
Department of Urban Engineering, The University of Tokyo,
7-3-1 Hongo, Bunkyo, Tokyo 113-8656, Japan
e-mail: hanaki@iniad.org