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BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

BIOENERGY FOR EUROPE: WHICH ONES FIT BEST?

102 7 Annex Wheat straw

102 7 Annex Wheat straw versus light oil and natural gas for heat production – Austria 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 -1500 -1000 -500 0 500 1000 1500 Austrian inhabitant equivalents per 100 TJ Natural gas Light oil 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 2,900 inhabitants in Austria in one year. In this case for example the amount of fossil fuel saved is equal to the amount which about 950 Austrian citizens would on average consume in one year (this is what is meant by „Austrian inhabitant equivalents“). Conclusions In Austria grain is cultivated on an area of approx. 0.9 to 1.0 million ha, approx. half of it is situated in arid areas and is thus suitable for energetic use. For a conclusion it is assumed that every year the straw yield of 100,000 ha is used for the production of heat. Compared to oil nearly 9 PJ of fossil energy and 0.6 Mt CO2 could be saved while nitrous oxide would increase insignificantly (+ 0.07 kt N2O). Straw can contribute almost 7 % to the demanded reduction in greenhouse gas emissions of 9.4 million tons if it substitutes oil or gas. Concerning acidification, eutrophication, summer smog and human toxicity the differences are rather insignificant. If straw substitutes oil the emissions of greenhouse gases and acidification are improved considerably, if straw substitutes gas advantages concerning summer smog can be observed.

7.1 Country specific life cycle comparisons 103 Biogas from swine excrement versus natural gas for combined heat and electricity production – Austria Use of fossil fuels Greenhouse effect Acidification Eutrophication Summer smog Nitrous oxide Human toxicity How to interpret the diagram Advantages for biofuel -4000 -3000 -2000 -1000 0 1000 2000 Austrian inhabitant equivalents per 100 TJ Advantages for fossil fuel The figure shows the results of comparisons between complete life cycles where natural gas for small scale combined heat and electricity production is substituted by biogas. The unit refers to an amount of 100 TJ net energy output, the ratio of heat to electricity is 1 to 1.11. In this case for example the amount of fossil fuel saved is equal to the amount which about 1,100 Austrian citizens would on average consume in one year (this is what is meant by "Austrian inhabitant equivalents"). Conclusions In 1999 the total Austrian livestock amounted to 2.14 million LSU (livestock unit). The share in pigs amounted to 412,510 LSU, including 111,176 LSU in 3118 undertakings of more than 50 LSU. The production of biogas out of excrement seems to be of interest especially with undertakings of such size. With the biogas production out of the liquid manure of 100,000 pig-LSU 0.3 PJ fossil fuel and 0.05 Mt CO2 can be saved. The effect on acidification, eutrophication, summer smog and nitrous oxide will be low (+ 0.15 kt SO2, + 0.09 kt NO3, - 0.03 kt ethylene eq. and + 0.0002 kt N2O). Biogas shows advantages concerning the use of fossil energy and clear advantages concerning the emission of greenhouse gases. 0.02 % of the Austrian demand in primary energy can be covered by the liquid manure of 5 % of the entire livestock. Biogas can contribute almost 0.6 % to the demanded reduction in greenhouse gas emissions of 9.4 million tons. The effects on the impact categories acidification, eutrophication, summer smog, nitrous oxide-emission and human toxicity are minimal.

Bioenergy Update 10-02 - General*Bioenergy