Review of life cycle assessment for biogas production in Europe

Resource strategy concerns and the need for mitigation of environmental impacts associated with energy generation from fossil fuels have increased the deployment of renewable energy carriers such as biogas. Biogas has beneficial environmental aspects such as waste treatment, production of energy from waste and general substrates and a better way to spread the fermented residues through improved nutrient and flow abilities. The objective of this study was to assess the status of biogas production and its effects on the environment due to greenhouse gases (GHG) and other environmental impacts. In this work, 15 life cycle assessment (LCA) studies of biogas systems from around Europe were reviewed. Biogas scenarios in all the studies had lower GHG intensities than their reference systems.The study shows that the type of feedstock, e.g., maize, grass or animal manure is a determining factor for the environmental impacts of biogas systems. Improving biogas plant technology and management by collecting the biogas during the storage of digested residues or installing a gas flare will improve the greenhouse gas balance of biogas systems. In comparison with traditional manure storage, anaerobic digestion of animal manure avoids methane (CH4) and nitrous oxide (N2O) emissions and adds to the substitution of artificial mineral fertilizer. Apart from the impacts resulting from the production of energy crops, acidification (AC) and eutrophication (EP) from biogas systems could be reduced by using combined heat and power units (CHPU) with catalytic converters and high efficiency.