title: Environmental life cycle assessment of producing willow, alfalfa and straw from spring barley as feedstocks for bioenergy or biorefinery systems.
abstract: The current study aimed at evaluating potential environmental impacts for the production of willow, alfalfa and straw from spring barley as feedstocks for bioenergy or biorefinery systems. A method of Life Cycle Assessment was used to evaluate based on the following impact categories: Global Warming Potential (GWP100), Eutrophication Potential (EP), Non-Renewable Energy (NRE) use, Agricultural Land Occupation (ALO), Potential Freshwater Ecotoxicity (PFWTox) and Soil quality. With regard to the methods, soil organic carbon (SOC) change related to the land occupation was calculated based on the net carbon input to the soil. Freshwater ecotoxicity was calculated using the comparative toxicity units of the active ingredients and their average emission distribution fractions to air and freshwater. Soil quality was based on the change in the SOC stock estimated during the land use transformation and land occupation. Environmental impacts for straw were economically allocated from the impacts obtained for spring barley. The results obtained per ton dry matter showed a lower carbon footprint for willow and alfalfa compared to straw. It was due to higher soil carbon sequestration and lower N2O emissions. Likewise, willow and alfalfa had lower EP than straw. Straw had lowest NRE use compared to other biomasses. PFWTox was lower in willow and alfalfa compared to straw. A critical negative effect on soil quality was found with the spring barley production and hence for straw. Based on the energy output to input ratio, willow performed better than other biomasses. On the basis of carbohydrate content of straw, the equivalent dry matter of alfalfa and willow would be requiring higher. The environmental impacts of the selected biomasses in biorefinery therefore would differ based on the conversion efficiency, e.g. of the carbohydrates in the related biorefinery processes.
authors.affiliation: Department of Agroecology, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark. Electronic address: ranjan.parajuli@agro.au.dk.
authors.forename: Ranjan
authors.initials: R
authors.lastname: Parajuli
authors.affiliation: Department of Agroecology, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Marie Trydeman
authors.initials: MT
authors.lastname: Knudsen
authors.affiliation: Department of Agroecology, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Sylvestre Njakou
authors.initials: SN
authors.lastname: Djomo
authors.affiliation: Department of Management Engineering, Technical University of Denmark, Building 424, DK-2800 Lyngby, Denmark.
authors.forename: Andrea
authors.initials: A
authors.lastname: Corona
authors.affiliation: Department of Management Engineering, Technical University of Denmark, Building 424, DK-2800 Lyngby, Denmark.
authors.forename: Morten
authors.initials: M
authors.lastname: Birkved
authors.affiliation: Department of Agroecology, Aarhus University, Blichers Allé 20, DK-8830 Tjele, Denmark.
authors.forename: Tommy
authors.initials: T
authors.lastname: Dalgaard
keywords: Biomass utilization efficiency; Biorefinery feedstock; Energy crops; Environmental sustainability; Land use change; Toxicity