BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

4.2 European results: biofuels compared to fossil fuels 57
4.2.6 ETBE versus MTBE for transportation (components of gasoline)
Use of fossil fuels
Greenhouse effect
Acidification
Eutrophication
Summer smog
Nitrous oxide**
Human toxicity**
* How to interpret the diagram
Advantages for
biofuel
Advantages for
fossil fuel
-1000 -800 -600 -400 -200 0 200 400 600 800 1000
European inhabitant equivalents* per 1 billion km
The figure shows the results of complete life cycle comparisons where gasoline with component ETBE
from sugar beet (12 vol. % = 10 % of energy content) is used in passenger cars instead of gasoline with
fossil MTBE (12 vol. %). The results are given for a distance of 1 billion km being covered by passenger
cars using the gasoline with the bio-component instead of fossil component. This is equivalent to
the average annual mileage of about 40,000 Europeans. In this case for example the amount of greenhouse
gas emissions that is being saved by substituting MTBE by ETBE is equal to the amount which
nearly 800 European citizens would on average generate in one year (this is what is meant by “European
inhabitant equivalents”).
Remarks and conclusions
The results show that both ETBE as well as MTBE have certain ecological advantages and disadvantages.
• Advantages of the biofuel: use of fossil fuels, greenhouse effect
• Advantages of the fossil fuel: acidification, eutrophication
• Low or no significance: summer smog
The data for ozone depletion and human toxicity tend to have a high uncertainty. Therefore these categories
should not be included in the final assessment. (**See Chapter 4.1.2 and for details on all impact
categories 3.3 and 3.4)
A further assessment in favour of or against ETBE or MTBE cannot be carried out on a scientific
basis, because for this purpose subjective value judgements regarding the individual environmental
categories are required which differ from person to person.