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BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

134 7 Annex Ecological

134 7 Annex Ecological aspects II: impacts related to saved energy – Germany Greenhouse effect Acidification Eutrophication Summer smog Nitrous oxide** Human toxicity** * How to interpret the diagram Advantages for fossil fuel Advantages for biofuel Triticale Willow Miscanthus RME ETBE Straw -1000 -500 0 500 1000 1500 German inhabitant equivalents* per 100 TJ of fossil energy saved The figure shows the results of complete life cycle comparisons where all biofuels investigated by Germany 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 Germany in one year. (This is what is meant by “German inhabitant equivalents”.) On the other hand, in this case for every 100 TJ of energy saved an amount of N2O is emitted that is equal to that on average generated by 8,400 German inhabitants in one year. Note that in this diagram the advantages of the fossil fuels are on the left hand side and vice versa. Remarks and conclusions Comparing the investigated bioenergy carriers (in turn compared to their fossil counterparts) against each other, the following result emerges: • Greenhouse effect: for all biofuels ensue. This effect is the greatest for triticale and lowest for RME. • Acidification: apart triticale all biofuels have negative impacts in this category, particularly RME. For triticale the results are non-significant. • Eutrophication: all biofuels show disadvantages. • Summer smog: willow and triticale show slight advantages, wheat straw and Miscanthus show slight disadvantages. The results of RME and ETBE are non-significant. 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. Taking the land use efficiency of the various biofuels into account (see previous section), triticale appears to achieve the best overall results and RME the worst. A further assessment in favour of or against one of the biofuels 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. 8426

7.1 Country specific life cycle comparisons 135 7.1.5 Country specific results – Greece Within the context of this project, the various participating countries investigated different biofuels in comparison to their respective fossil counterparts, as was explained in Chapter 2. While the results for the whole of Europe are presented in Chapter 4, in this chapter the results for the individual countries are presented, on which the European results are based. In the following section the results for all those life cycle comparisons that were investigated in Greece are presented: • Wheat straw versus light oil and natural gas for district heating. • Sunflower seed oil methyl ester (SME) versus fossil diesel fuel for transportation. • Biogas from liquid swine manure versus natural gas for combined heat and power production. In addition, for each country comparisons between its various biofuels have been carried out in order to assess which one is the most suitable in ecological terms for a specific objective. This lead to a number of different questions, in the light of which the various biofuels were compared. Greece looked at one of these and namely: Saving of energy resources: SME, biogas and straw. For more information on these comparisons the reader is referred to Chapter 2. As for the European chains, the life cycle comparisons were carried out with regard to specific environmental impact parameters. These were: • Use of fossil fuels • Greenhouse effect • Acidification • Eutrophication • Summer smog • Nitrous oxide • Human toxicity The criteria according to which these were selected as well as an explanation of their meanings can be found in the Chapters 3.3 and 3.4. How to interpret the diagrams Each diagram corresponds to one environmental parameter for which the results for the biofuels and their fossil counterparts are presented in different columns side by side. The values are expressed per MJ useful energy, namely the net energy that is available to the end user. Each column is divided in two differently coloured parts that correspond to different phases in the life cycles of the fuels under study. Agriculture/forestry part includes all processes connected to the production of the raw material until harvesting of the energy crop or collection of the residue while agricultural reference system includes the reference use of the land or the residue. Processing & utilisation includes all processes after harvesting/collection until energy production and waste disposal on the biofuel’s side and fossil fuel life cycle the whole life cycle (production, use and waste disposal) of the fossil fuels . In the case of biogas all processes are included in the agriculture/forestry part. For reasons of clarity of presentation, the minimum-maximum evaluations have not been presented in the result graphs. For more information on this the reader is referred to Chapter 4.1.3.

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