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13.1.1.1 Biofuels and Their Environmental Impact
Biofuels are carbon neutral at the usage stage and, because they are renewable, can
be studied as a means of addressing global warming. However, there are many items
that need to be considered including changes in land use, encompassing forest conservation, as well as impacts on air, water, and soil quality and impacts on water
resources, ecosystems, and biodiversity. It is also important to assess the indirect
impact on land use. For these reasons, biofuels have been studied by the Scientific
Committee on Problems of the Environment (SCOPE) of International Council for
Science (ICS) as a worldwide body and by the USA and other countries (SCOPE
2008; UDAID 2009; USEPA 2011), in addition to existing study by the United
Nations organizations cited later in this chapter. In order to assess these items appropriately, it is necessary to study deployment strategies from a global perspective.
The United Nations Environmental Programme (UNEP 2009) reports that the
GHG balance in LCA for biofuels varies widely depending on the raw materials,
biofuel generation technology, and methodological assumptions. For example, bioethanol from sugarcane can reduce GHG emissions by between 70% and 140%
compared with gasoline, whereas corn can reduce GHG emissions as much as 60%
but may also increase them by as much as 5%. Biodiesel from palm oil can reduce
GHG emissions by as much as 80%, but when palm oil is harvested by converting
natural forests into plantations, it can increase GHG emissions by 870–2000% when
taking into account the impact of the land use change (UNEP 2009). In other words,
biofuels do not always have the effect of reducing GHG emissions when compared
with fossil fuels such as gasoline and diesel oil, if we consider direct emissions from
the harvesting of biofuel crops and indirect emissions from land use changes.
Furthermore, the use of fertilizers causes eutrophication of water bodies and
acidification of rainwater, while decomposition of fertilizer generates nitrogen
oxides that have an impact on ozone layer depletion. It has been pointed out that
these impacts are insufficiently covered by LCAs and require future study (UNEP
2009).
In addition to GHG emissions, land use change can have a potentially major
negative impact on biodiversity by changing living creatures’ habitats, except where
wasteland is used to cultivate energy crops. Jatropha has drawn interest as a raw
material crop for biofuel but is also identified as being a potentially invasive species
that could disrupt ecosystems.
It is also necessary to consider the nutrient contamination of water bodies as a
result of intensive agriculture. There is the additional concern that irrigation and
other practices involved in harvesting biofuel crops will also increase consumption
of agricultural water and, combined with extreme weather events (flooding and
droughts) caused by climate change, could create issues for water resource management (UNEP 2009; World Bank a 2010).
The use and combustion of biofuels reduce localized emissions of some air pollutants such as particulate matter (PM10), volatile organic compounds (VOCs), sulfur oxide, and carbon monoxide but are also reported to increase nitrogen oxide
(NOx) and aldehyde emissions. Biodiesels are reported to increase NOx emissions
S. Arai and H. Matsuda
13.1.1.1 Biofuels and Their Environmental Impact
Biofuels are carbon neutral at the usage stage and, because they are renewable, can
be studied as a means of addressing global warming. However, there are many items
that need to be considered including changes in land use, encompassing forest conservation, as well as impacts on air, water, and soil quality and impacts on water
resources, ecosystems, and biodiversity. It is also important to assess the indirect
impact on land use. For these reasons, biofuels have been studied by the Scientific
Committee on Problems of the Environment (SCOPE) of International Council for
Science (ICS) as a worldwide body and by the USA and other countries (SCOPE
2008; UDAID 2009; USEPA 2011), in addition to existing study by the United
Nations organizations cited later in this chapter. In order to assess these items appropriately, it is necessary to study deployment strategies from a global perspective.
The United Nations Environmental Programme (UNEP 2009) reports that the
GHG balance in LCA for biofuels varies widely depending on the raw materials,
biofuel generation technology, and methodological assumptions. For example, bioethanol from sugarcane can reduce GHG emissions by between 70% and 140%
compared with gasoline, whereas corn can reduce GHG emissions as much as 60%
but may also increase them by as much as 5%. Biodiesel from palm oil can reduce
GHG emissions by as much as 80%, but when palm oil is harvested by converting
natural forests into plantations, it can increase GHG emissions by 870–2000% when
taking into account the impact of the land use change (UNEP 2009). In other words,
biofuels do not always have the effect of reducing GHG emissions when compared
with fossil fuels such as gasoline and diesel oil, if we consider direct emissions from
the harvesting of biofuel crops and indirect emissions from land use changes.
Furthermore, the use of fertilizers causes eutrophication of water bodies and
acidification of rainwater, while decomposition of fertilizer generates nitrogen
oxides that have an impact on ozone layer depletion. It has been pointed out that
these impacts are insufficiently covered by LCAs and require future study (UNEP
2009).
In addition to GHG emissions, land use change can have a potentially major
negative impact on biodiversity by changing living creatures’ habitats, except where
wasteland is used to cultivate energy crops. Jatropha has drawn interest as a raw
material crop for biofuel but is also identified as being a potentially invasive species
that could disrupt ecosystems.
It is also necessary to consider the nutrient contamination of water bodies as a
result of intensive agriculture. There is the additional concern that irrigation and
other practices involved in harvesting biofuel crops will also increase consumption
of agricultural water and, combined with extreme weather events (flooding and
droughts) caused by climate change, could create issues for water resource management (UNEP 2009; World Bank a 2010).
The use and combustion of biofuels reduce localized emissions of some air pollutants such as particulate matter (PM10), volatile organic compounds (VOCs), sulfur oxide, and carbon monoxide but are also reported to increase nitrogen oxide
(NOx) and aldehyde emissions. Biodiesels are reported to increase NOx emissions
S. Arai and H. Matsuda