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BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

72 4 Environmental

72 4 Environmental results: presentation, discussion and interpretation 4.4.4 Germany The following biofuels were investigated: • Triticale versus coal for electricity production • Miscanthus versus heating oil and natural gas for district heat production • Willow versus heating oil and natural gas for district heat production • Wheat straw versus heating oil and natural gas for district heat production • Rape seed oil methyl ester versus fossil diesel fuel for transportation • ETBE from sugar beet versus MTBE for transportation The German results (see Table below) show a quite unambiguous picture: all the biofuels under study have positive impacts because they ⇒ decrease the use of non-renewable, fossil fuels, ⇒ decrease the emissions of CO2 and thus decrease the possible greenhouse effect, but ⇒ with regard to environmental problems such as acidification, eutrophication and summer smog, the fossil fuels come out as most advantageous in most cases. These results cannot directly be used for recommendations concerning which biofuels should be supported, if any, because this recommendation depends upon the relative importance which the reader / decision maker assigns to the different environmental impact categories. Overall it can be said that biofuels should only be supported if the decision makers value saving of fossil fuels and greenhouse effect relatively higher than the other environmental impacts. (For more details see Chapter 7.1.4.) Impact category Triticale Willow Miscanthus RME ETBE Wheat straw Use of fossil fuels + + + + + + Greenhouse effect + + + + + + Acidification +/- - - - - - Eutrophication - - - - - - Summer smog + + +/- +/- +/- +/- (+) advantage for biofuel (-) advantage for fossil fuel (+/-) insignificant or ambiguous result (see Chapter 4.1.4) Regarding the comparisons between the various biofuels in the light of different objectives, Germany investigated two application fields and two ecological aspects: • Heat production: Miscanthus, willow and straw. Whereas there is no significant difference in the results concerning the use of fossil energy and greenhouse effect, with the other environmental parameters no clear ranking occurs. Thus, the final ranking must be done by subjectively according to the priorities of the decision maker • Biofuels for transportation: RME and ETBE. In all environmental categories under investigation ETBE comes out better than RME. • Efficiency of land use: triticale, willow, Miscanthus, RME and ETBE. Triticale achieves good results except for the categories eutrophication and N2O, whereas RME is the least efficient biofuel under concern, but it scores well on eutrophication. Miscanthus and ETBE achieve similar results in most categories. Similar to RME, willow has a relatively low efficiency regarding the use of fossil fuels and the greenhouse effect, but has also relatively low impacts regarding the other categories. • Impacts related to saved energy: triticale, willow, Miscanthus, RME, ETBE and wheat straw. The solid fuels all save more CO2 emissions per MJ of energy saved than the liquid fuels for transport. With regard to acidification, triticale is the only biofuel that shows a (very small) advantage; while RME has the largest impact in this category. With regard to eutrophication, straw has a much lower impact than all other biofuels. Note that the rankings given here refer exclusively to the reliable and quantifiable parameters investigated in this project. For a further assessment other parameters must be included as were considered in this study (see particularly Chapter 6).

4.4 Summary of country specific results 73 4.4.5 Greece Within the context of this project the life cycle comparisons investigated for Greece were: • Wheat straw versus light oil and natural gas for district heating. • Sunflower oil methyl ester (SME) versus fossil diesel fuel for transportation. • Biogas from liquid swine manure versus natural gas for combined heat and power production. According to the results, presented in summary in the table below, all biofuels studied for Greece present advantages and disadvantages compared to their respective fossil counterparts, 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 more favourable results than their fossil counterparts. 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 nitrous oxide, acidification and eutrophication all biofuels appear disadvantageous compared to their fossil counterparts. (Note that the data for ozone depletion tend to have a high uncertainty – see Chapter 4.1.2 – and therefore these impact categories should not be included in the final assessment.) 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 less favourable 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 (as with ozone depletion however, the data for human toxicity tend to have a high uncertainty and therefore these impact categories should not be included in the final assessment). 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 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.

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