The Diversity in the Interpretation of Data

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Numerous LCAs have been published to date, which tackle a wide variety of issues such as the comparisons of raw materials for certain products. However, different studies are not easily comparable, sometimes leading to contradicting conclusions. Table 12.7 shows an assortment of studies regarding CO2 emissions for the production of ethanol as fuel alternative, derived from renewable feedstocks. In the case of bioethanol made from sugarcane the standard deviation of the pictured sources is around 30% for the base case. A study conducted by Fehrenbach et al.

12.5 Determination of CO2 Emissions in Processes of Chemical Industry | 441 Table 12.7 CO2 Emissions forthe production ofbioethanol.


Sugarcane Sugarcane Sugarcane Sugarcane






Other agricultural operations3'

Production of biomass

Industrial conversion


Total emissions (Base case)

Credits for avoided emissionsd)

Total emissions (With credits)

Direct LUC

Total emissions (Direct LUC)

Indirect LUC

Total emissions (Direct and indirect LUC)






Latin America


Fehrenbach European et al. [36] Commission [22]


180.1 213.9

48.5 262.4



North America







Fehrenbach et al. [36]



47.8 152.8

69.5 222.3

All figures given in g CO2eq MJ

a) For example, soil emissions, transport of biomass, etc.

b) Author's estimate. When transported to Europe 5.5 g CO2eq MJ_1.

c) If transported to Europe 7.7g CO2eqMJ-1.

d) Byproducts (e.g., bagasse in the case of sugarcane) are used for energy generation. Source: Based on [20], [21], [23], [36].

[ 36] compared the production of ethanol from sugarcane in Latin America and from wheat in Europe. In the base case Latin American bioethanol seems to be more sustainable in terms of CO [ emissions than European bioethanol. But, if one considers the land use change (LUC) the conclusions could shift to the opposite.

Attempts to standardize LCAs have lead to the 'Code of Practice' [37] developed by the Society of Environmental Toxicology and Chemistry (SETAC) and the ISO 14040:2006 [38] standard established by the International Organization for Standardization (ISO). They provide principles and frameworks for the generation of LCAs. Regardless, a comparison between two separate studies from different institutions or individuals remains difficult (the studies shown in Table 12.7 follow these standards). The resulting climatic impact for the same issue can be positive or negative depending on the scope, the set boundaries, as well as different influencing drivers and different assumption settings. Moreover, a lack of transparency and the usage of aggregated data make a comparison tricky, as tradeoffs between diverse aspects occur regularly (e.g., costs vs. climate impact; see also Section 12.6). One of the topics most often assessed is that of the above-mentioned bioethanol for the use as fuel or as a fuel additive [21]. An overview of LCAs covering bioethanol for the use in automotive gasoline was performed by Hedegaard et al. and von Blottnitz and Curran [39, 40]. The main conclusion of these studies is that bioetha-nol leads in general to a net energy gain. Other environmental impact factors such as acidification, human toxicity and ecological toxicity impacts, however, tend to be more unfavorable for bioethanol ,40], In terms of reducing GHG emissions, recent doubts have been raised towards the application of biofuels. One example discussed was the conversion of land for industrial crop production, especially that of peat-land in Indonesia and Malaysia, since it is burdened with a carbon debt which may take several generations to approach break-even [41]. Other questions of biofuel impact have been posed, such as a disruption of food supply, increased water pollution, loss of biodiversity, and a lack of benefit of those directly affected by biofuels production [20] .

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