Environmental Engineering Reference
In-Depth Information
efficient way to treat waste. Another study has linked MIMES/WASTE with an energy
system model, MARTES, by using both models in two case studies (Olofsson, 2001).
Life cycle assessment (LCA) is a widely used method for evaluating the environmental
impact of products and services (Rydh et al, 2002). How to perform an LCA is laid down in
ISO standards. The methodology in short has four steps:
1. Goal and scope definition
2. Inventory analysis, where data is compiled
3. Life cycle assessment involving classification of data to different environmental
impacts;
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characterization, where the data is analysed as to the extent to which they
contribute to different impacts; and valuing or weighting. The step of valuing is however
in question since it is considered to be subjective.
4. Interpretation of results.
One model for assessing waste management options based on LCA methodology is
ORWARE, see e.g. Eriksson et al (2002). This model handles the double functions of waste
incineration by compensatory systems, in line with LCA methodology. A compensatory
system, e.g. for waste incineration, apart from the function of waste treatment, also means
district heating and/or electricity. To assess the robustness of the results, a sensitivity analysis
of these compensatory systems is recommended, e.g. if district heating is produced by
biomass fuel or oil. Finnveden and Ekvall (1998) compare LCA studies of recycling versus
incineration of paper, and show the importance of assumptions made with regard to
compensatory systems and also take up the question of biomass; what is made of the saved
biomass when recycling paper? This question indicates a need to define how biomass should
be regarded; should it be regarded as a scarce resource?
A number of studies have attempted to estimate the potential biomass supply. Ericsson
and Nilsson (2006) have assessed the potential in the 15 old EU countries (EU15), 8
newcomers
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and 2 candidate countries
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(ACC10) and also Belarus and Ukraine, and
compared it with the EU's targets for increasing the proportion of the total primary energy
supply produced with biomass. Their assessment shows that, subject to certain restrictions on
land availability, the potential is up to 11.7 EJ/year in the EU15 and 5.5 EJ/year in the
ACC10. These figures can be compared with the fact that total energy supply in the EU15 in
2001 was 62.6 EJ. There are no resource limitations in meeting the EU target of 5.6 EJ/year in
the EU15 by 2010, though it will probably not be met due to slow implementation of the
renewable energy policy. Berndes et. al. (2003) are reviewing 17 studies on the contribution
of biomass in future global energy supply. Both demand-driven studies
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and resource
studies
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were reviewed. The resource studies showed large variations in the amount of
biomass fuels. The studies with the highest assumptions assumed vast areas of Africa to be
given over to energy crop production with exports to the rest of the world. The article
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Such as greenhouse gases, eutrophication, acidification.
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Cyprus and Malta are not included.
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Bulgaria and Romania.
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The meaning of demand-driven studies is the potential of energy from biomass in competition with other energy
carriers.
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The meaning of resource-driven studies is the possibility to produce biomass for energy purposes in competition
with other land uses, such as food production.
