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BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

140 7 Annex In the

140 7 Annex In the impact category human toxicity the only biofuel that contributes to savings in the related emissions is SME with net savings of 3,430 m 3 eq./MJ useful energy. Both biogas and straw present worse results than their fossil counterparts. The least favourable for this impact category is straw emitting more than 20,000 m 3 eq./MJ useful energy higher than light oil or natural gas due to increased benzene and dioxins emissions from straw combustion. The respective value for biogas versus natural gas is 2,014 m 3 eq./MJ useful energy. It is clear that SME is the most advantageous biofuel in this impact category and straw the most disadvantageous. The data for human toxicity tend to have a high uncertainty (see chapter 4.1.2) and there fore these impact categories should not be included in the final assessment. Country summary and conclusions All biofuels studied for Greece (SME, straw and biogas) present advantages and disadvantages compared to the reference systems, while the comparison of biofuels among one another does not come to a final conclusion. However the following remarks might be useful: In the impact categories Use of fossil fuels and Greenhouse effect all the biofuels under study present better results than their fossil reference system. Net savings in finite energy are higher when SME replaces diesel oil while biogas instead of natural gas saves more than two times higher global warming related emissions than the other two biofuels under study. In the impact categories Acidification, Eutrophication and Nitrous oxide all biofuels appear disadvantageous compared to their fossil counterparts. Biogas proves to be the least disadvantageous in terms of N2O emissions and straw concerning acidification and eutrophication related emissions. Concerning Summer smog creation all biofuels appear more favourable than their fossil counterparts with the exception of wheat straw versus light oil. Savings in the related emissions are higher in the biogas chain. All biofuels with the exception of SME give worse results than the fossil fuels they are compared with in the impact category Human toxicity, indicating that SME is the most favourable biofuel in this impact category. Impact categories SME Wheat straw vs. light oil Wheat straw vs. nat. gas Biogas Use of fossil fuels + + + + Greenhouse effect + + + + Acidification - - - - Eutrophication - - - - Summer smog + - + + Nitrous oxide** - - - - Human toxicity** + - - - (+) advantage for the biofuel (-) disadvantage for the biofuel ** The data for ozone depletion and human toxicity tend to have a high uncertainty (see chapter 4.1.1) and there fore these impact categories should not be included in the final assessment. Taking into account the above remarks no further assessment in favour or against the use of the biofuels under study instead of their fossil counterparts or one biofuel instead of another can be carried out on a scientific basis. Subjective value judgements regarding the individual environmental categories are required for this purpose, which differ from person to person.

7.1 Country specific life cycle comparisons 141 7.1.6 Country specific results – Italy 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 are presented that were investigated in Italy. These are: • Sunflower oil methyl ester versus fossil diesel fuel • Traditional firewood versus heating oil and natural gas • Biogas versus natural gas 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. Of these, Italy looked at one ecological aspect, namely impacts related to saved energy, comparing SME, traditional firewood and biogas. 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. For reasons of clarity of presentation, the results of 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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