[pp.1-6]

Validity of Bio-Ethanol as a Countermeasure against Global Warming

Satoshi MATSUDA （Shizuoka University）

Abstract:
Recently the fuel ethanol production from crops has attracted much attention not only in the US, EU and Brazil, but also in Japan because the bio-ethanol is perceived as being "carbon neutral" and useful as a countermeasure against global warming. In fact, the Japanese government has declared that the production of 780 thousand kiloliters of bio-ethanol, which is equivalent to 500 thousand kiloliters of oil and could reduce CO2 production by 1.2 million tons, should be a goal for 2010. However, there are many problems in bio-ethanol production, pointed out from various points of view. First of all, the utility of bio-ethanol production as a countermeasure against global warming should be examined carefully and objectively. In this study, an assessment on the validity of bio-ethanol production and use was tried as to quantitatively estimate the effectiveness of bio-ethanol. For this purpose, a new index of CO2 emission reduction “ν” was proposed and formulated as a function of the ratio of energy output to input “μ”, and used as criteria for estimating the utility of bio-ethanol. As a result, it was concluded that the ethanol from crops is never "carbon neutral" because additional energy input is required to produce the fuel and has only a minimal contribution to the issue of global warming. It also even has the possibility of increasing CO2 emissions. The amount of bio-ethanol is also rather small when compared with the fuel demand for transportation. The economic analysis of bioethanol production has also indicated that the financial benefits of bio-ethanol were not positive figures.

Key Word:
bio-ethanol, carbon neutral, index of CO2 emission reduction, energy balance

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