Life Cycle Assessment of electricity production in Italy from anaerobic co-digestion of pig slurry and energy crops
Articolo
Data di Pubblicazione:
2014
Citazione:
Life Cycle Assessment of electricity production in Italy from anaerobic co-digestion of pig slurry and energy crops / L. Lijó, S. González García, J. Bacenetti, M. Fiala, G. Feijoo, J.M. Lema, M.T. Moreira. - In: RENEWABLE ENERGY. - ISSN 0960-1481. - 68:(2014), pp. 625-635. [10.1016/j.renene.2014.03.005]
Abstract:
This study aims to evaluate the environmental consequences and energy requirements of a biogas
production system and its further conversion into bioenergy by means of the Life Cycle Assessment (LCA)
methodology. To do so, an Italian biogas plant operating with pig slurry and two energy crops (maize and
triticale silages) as feedstock was assessed in detail in order to identify the environmental hotspots. The
environmental profile was estimated through six impact categories: abiotic depletion potential (ADP),
acidification potential (AP), eutrophication potential (EP), global warming potential (GWP), ozone layer
depletion potential (ODP) and photochemical oxidation potential (POFP). An energy analysis related to
the cumulative non-renewable fossil and nuclear energy demand (CED) was also performed, considering
this indicator as an additional impact category.
According to the results, the biomass production subsystem was identified as the main environmental
key issue in terms of ADP, AP, EP, ODP and CED, with contributions ranging from 26% to 61% of the total
impact. Regarding ADP, ODP and CED, these results are mainly related with diesel requirements in
agricultural machinery, derived combustion emissions and mineral fertilizers production. Concerning AP
and EP the production field emissions derived from fertilizers application was observed as the main
contributor. Concerning GWP, this step presents an environmental credit due to the uptake of CO2 during
crop growth, which contributes to offset the GHG emissions. The bioenergy production plant signifi-
cantly contributes to the environmental impact in categories such as GWP (43%) and POFP (59%), mostly
related with emissions produced in the gas engine and biogas losses. Emissions derived from digestate
storage contribute to AP (52%) and EP (41%). The use of the digestate as an organic fertilizer has a
beneficial role because this action avoids the production and use of mineral fertilizers.
A sensitivity analysis was also conducted to assess the influence of variations in important parameters
of biogas systems. The environmental profile of the biogas system turned out to be highly dependent on
the selection of system boundaries and the allocation method.
To sum up, this study aims to assess the environmental performance of a biogas technology available
not only in Italy but also in other European countries. The environmental analysis of the process under
study highlights the environmental benefits of the co-digestion processes, which not only produces
biofuel but also reduces the disposal of solid wastes and produces digestate, with special value in the
fertilization of agricultural soil.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Anaerobic co-digestion; Bioenergy; Environmental impact; Maize silage; Organic waste; Triticale silage
Elenco autori:
L. Lijó, S. González García, J. Bacenetti, M. Fiala, G. Feijoo, J.M. Lema, M.T. Moreira
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