BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

4.3 European results: biofuels for specific objectives 67
4.3.4 Ecological aspects II: impacts related to saved energy
Greenhouse effect
Acidification
Eutrophication
Summer smog
Nitrous oxide**
Human toxicity**
-1530
* How to interpret the diagram
Advantages for
biofuel
Triticale
Willow
Miscanthus
RME
SME
ETBE
Firewood
Straw
Biogas
Advantages for
fossil fuel
-1500 -1000 -500 0 500 1000 1500
European inhabitant equivalents* per 100 TJ of fossil energy saved
The figure shows the results of complete life cycle comparisons where all investigated biofuels are used
for energy production instead of their respective fossil counterparts. The results for the various categories
are given with reference to the category use of fossil fuels, i.e. 100 TJ of fossil energy saved. For
example, for every 100 TJ of fossil energy saved through the substitution of diesel fuel by RME, the
amount of greenhouse gas emissions avoided is equal to those on average generated by about 300 inhabitants
of Europe in one year. (This is what is meant by “European inhabitant equivalents”.)
Remarks and conclusions
Comparing the investigated bioenergy carriers (in turn compared to their fossil counterparts) against
each other, the following result emerges:
• Greenhouse effect: all biofuels have advantages over the fossil fuels. This effect is by far the greatest
for biogas, followed by triticale and lowest for RME.
• Acidification: apart from firewood and triticale all biofuels have negative impacts in this category,
particularly biogas and RME. For firewood and triticale the results are non-significant.
• Eutrophication: only SME shows an advantage.
• Summer smog: biogas, willow and triticale show slight advantages, wheat straw and Miscanthus
show slight disadvantages. The results of RME, SME and ETBE as well as for firewood are nonsignificant.
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.)
For most of the biofuels a negative “side-effect” results compared to the fossil fuels regarding most of
the categories apart from the greenhouse effect. RME shows the worst results compared to all other
biofuels except for Miscanthus and wheat straw with regard to the category summer smog. The results
for all other biofuels are more ambiguous. Thus for every MJ fossil energy saved, an additional ozone
depletion effect results for all biofuels except for firewood. For SME and RME this effect is relatively
9088
5012