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152 7 Annex Human

152 7 Annex Human toxicity – The Netherlands m3/MJ useful energy 45000 40000 35000 30000 25000 20000 15000 10000 5000 0 willow heat natural gas heat Processing & utilisation Agriculture/forestry part Fossil fuel life cycle Agricultural reference system Miscanthus heat natural gas heat hemp electricity natural gas electricity sugar beet ETBE transport MTBE transport biogas electricity + heat natural gas electricity + heat A remarkable difference between the chains is the high impact on human toxicity for both ETBE and MTBE which is due to the energy production part. Using ETBE instead of MTBE gives slightly more impact on human toxicity. The energy production out of Miscanthus and willow has a much higher impact on human toxicity compared to the impact of the fossil fuel counterpart. This difference is partly caused by a significant higher emission of dioxines during the combustion of Miscanthus and willow compared with combustion of natural gas. This emission is much higher than the emission of dioxines from combustion of biogas and hemp. The use of pesticides in energy crops is limited and for willow and Miscanthus even (close to) zero. For human toxicity the effect of pesticides is only reflected in the hemp chain. Due to its complexity, persistent toxicity and ecotoxicity have been left out of the quantitative assessment. In case they would have been included, the use of pesticides in general would have shown a worse score for energy crops as compared to fallow land. Four comparisons In this part, the four comparisons described in the introduction will be discussed. Heat production with perennial crops: willow, Miscanthus Summarising the results, it is obvious that the perennials willow and Miscanthus have in general comparable results. Both biofuels have advantages on the use of fossil fuels and the greenhouse effect. The energy production per ha of Miscanthus is higher than willow, which indicates that Miscanthus uses the land more efficient. Both biofuels also have a positive result on summer smog but this advantage is larger for willow than for Miscanthus. This is caused by a higher emission of VOC with combustion of Miscanthus. For ozone depletion, acidification and eutrophication willow and score worse than natural gas for the production of heat. The can partly be explained by the more intensive use of the land (fertilisation) compared with fallow. Besides that, the energy production part of Miscanthus causes a high effect on ozone depletion and acidification compared to the reference and willow. Miscanthus combustion has a higher N2O and NOx emission which affects the ozone depletion and acidification.

7.1 Country specific life cycle comparisons 153 Miscanthus has an obvious disadvantage for human toxicity whereas this disadvantage is smaller for willow. This is due to dioxine emission from Miscanthus combustion. Different types of bioenergy with annual crops: hemp, sugar beet for ETBE In general the results for the annuals sugar beet and hemp are comparable. Like willow and Miscanthus both biofuels score well on the use of fossil fuels, greenhouse effect and summer smog. The production of useful energy per ha is larger from hemp then from sugar beet for ETBE. Hemp has larger disadvantages for ozone depletion and eutrophication compared to ETBE. Especially the more intensive fertilisation of hemp causes a larger effect on ozone depletion and eutrophication. For acidification ETBE has a minor disadvantage compared with the disadvantage of. For hemp, the relatively high score for acidification due to the agricultural part relates to ammonia emission. If we compare the level of impact for human toxicity it can be seen that ETBE has a much higher impact than hemp. Nevertheless the difference between the fossil fuel and the biofuel is comparable for ETBE and hemp. The minor disadvantage of hemp is caused by the use of pesticides. The disadvantage of sugar beet for ETBE is due to the energy production part. Electricity: biogas, hemp The results for biogas and hemp are comparable for all the environmental parameters except for ozone depletion. Both biofuels have a positive result for the use of fossil fuels, greenhouse effect and summer smog. Nevertheless the advantages for biogas for greenhouse effect and summer smog are higher than for hemp. This is partly caused by the reduction of methane emission because biogas out of manure is used as a biofuel instead of applying non-treated manure on the field. For acidification and eutrophication biogas and hemp have disadvantages compared to the fossil fuels. For hemp this is due to the more intensive fertilisation. For it is due to the higher emission of ammonia during spreading of the fermented manure and the higher emission of NOx during the combustion of the biogas. Both biofuels have a comparable minor disadvantage on human toxicity. A large difference between hemp and biogas is the highly negative effect of hemp and the positive effect of biogas on ozone depletion. The agricultural part of hemp causes a high emission of N2O whereas biogas leads to less emission of N2O compared to the fossil fuel reference. Bioenergy: annual crops, perennial crops The perennials willow and Miscanthus and the annuals sugar beet for ETBE and hemp have advantages for the use of fossil fuels , greenhouse effect and summer smog. For the use of fossil fuels and greenhouse effect the perennial crops have a larger impact than the annuals. The perennial and annual crops both have disadvantages for ozone depletion and eutrophication. With regard to eutrophication by ETBE, this is only minor compared to the disadvantage of willow, Miscanthus and hemp. For acidification and human toxicity, the annuals and perennials differ but the picture is not clear. ETBE has a minor disadvantage which is mainly caused by a bigger effect in the energy production part for human toxicity and by a bigger effect in the agricultural part for acidification. The disadvantage of hemp can be explained with the more intensive fertilisation (eutrophication) and pesticide use (human toxicity). The negative scores of perennials on these themes do not relate to the relative clean agricultural production part, but to the emissions in the energy production phase.

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