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BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

130 7 Annex Wheat straw

130 7 Annex Wheat straw versus light oil / natural gas for district heat production – Germany Use of fossil fuels Greenhouse effect Acidification Eutrophication Summer smog Nitrous oxide** Human toxicity** Advantages for biofuel * How to interpret the diagram Advantages for fossil fuel Light oil Natural gas -1000 -500 0 500 1000 1500 2000 German inhabitant equivalents* per 100 TJ The figure shows the results of comparisons between complete life cycles where light oil and natural gas respectively are substituted by wheat straw for heat production. The unit refers to an amount of 100 TJ of heat. This is equivalent to the average heat requirement of about 25,000 inhabitants of Germany in one year or a wheat straw production of about 1,300 ha/a. In this case for example the amount of fossil fuel saved if light oil is substituted by wheat straw is equal to the amount which more than 700 German citizens would on average consume in one year (this is what is meant by “German inhabitant equivalents”). Remarks and conclusions The results show that both wheat straw as well as light oil and natural gas have certain ecological advantages and disadvantages. • Advantages of the biofuel: use of fossil fuels, greenhouse effect, compared to natural gas only: summer smog (small) • Advantages of the fossil fuel: acidification, eutrophication, light oil only: summer smog • Low or no significance: – 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 wheat straw or light oil / natural gas 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.

7.1 Country specific life cycle comparisons 131 Technical applications I: heat production – Germany 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 Willow Miscanthus Straw -1000 -500 0 500 1000 1500 2000 2500 German inhabitant equivalents* per 100 TJ The figure shows the results of complete life cycle comparisons where straw, willow and Miscanthus respectively are used for heat production instead of light oil. The results are given for an amount of 100 TJ. This is equivalent to the average heat requirement of 25,000 inhabitants of Germany in one year. In this case for example the amount of greenhouse gas emissions that is being saved by substituting light oil by Miscanthus is equal to the amount which about 700 German citizens would on average generate in one year. (This is what is meant by “German inhabitant equivalents”.) Remarks and conclusions Comparing the four investigated bioenergy carriers (in turn compared to their fossil counterparts) against each other, the following result emerges: • Use of fossil fuels and greenhouse effect: all biofuels show quite similar advantages. • Acidification: all biofuels show disadvantages, willow the smallest, straw and Miscanthus similar. • Eutrophication: straw shows a small, the cultivated biofuels much bigger disadvantages. • Summer smog: willow shows a small advantage, straw and Miscanthus small disadvantages. 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.) Overall, Miscanthus has the least favourable results apart from the category eutrophication. 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.

Bioenergy Update 10-02 - General*Bioenergy