title: Nitrogen fertiliser production based on biogas - energy input, environmental impact and land use.
abstract: The aim of the present paper was to investigate the land use, environmental impact and fossil energy use when using biogas instead of natural gas in the production of nitrogen fertilisers. The biogas was assumed to be produced from anaerobic digestion of ley grass and maize. The calculations showed that 1 ha of agricultural land in south-west Sweden can produce 1.7 metric ton of nitrogen in the form of ammonium nitrate per year from ley grass, or 3.6 ton from maize. The impact on global warming, from cradle to gate, was calculated to be lower when producing nitrogen fertiliser from biomass compared with natural gas. Eutrophication and acidification potential was higher in the biomass scenarios. The greatest advantage of the biomass systems however lies in the potential to reduce agriculture's dependency on fossil fuels. In the biomass scenarios, only 2-4 MJ of primary fossil energy was required, while 35 MJ/kgN was required when utilising natural gas.
authors.affiliation: Swedish University of Agricultural Sciences, Department of Energy and Technology, PO Box 7032, SE750 07 Uppsala, Sweden. serina.ahlgren@et.slu.se
authors.forename: Serina
authors.initials: S
authors.lastname: Ahlgren
authors.forename: Sven
authors.initials: S
authors.lastname: Bernesson
authors.forename: Ke
authors.initials: K
authors.lastname: Nordberg
authors.forename: Per-Anders
authors.initials: PA
authors.lastname: Hansson
mesh_terms: D000383:Agriculture / Q000706:statistics & numerical data*; D056804:Biofuels / Q000706:statistics & numerical data*; D004735:Energy Transfer; D004777:Environment; D005308:Fertilizers / Q000706:statistics & numerical data*; D008954:Models, Biological; D009584:Nitrogen / Q000737:chemistry* / Q000378:metabolism*; D013548:Sweden
chemical_list: D056804:Biofuels; D005308:Fertilizers; D009584:Nitrogen