title: The environmental sustainability of anaerobic digestion as a biomass valorization technology.
abstract: This paper studies the environmental sustainability of anaerobic digestion from three perspectives. First, reference electricity is compared to electricity production from domestic organic waste and energy crop digestion. Second, different digester feed possibilities in an agricultural context are studied. Third, the influence of applying digestate as fertilizer is investigated. Results highlight that biomass is converted at a rational exergy (energy) efficiency ranging from 15.3% (22.6) to 33.3% (36.0). From a life cycle perspective, a saving of over 90% resources is achieved in most categories when comparing biobased electricity to conventional electricity. However, operation without heat valorization results in 32% loss of this performance while using organic waste (domestic and agricultural residues) as feedstock avoids land resources. The use of digestate as a fertilizer is beneficial from a resource perspective, but causes increased nitrogen and methane emissions, which can be reduced by 50%, making anaerobic digestion an environmentally competitive bioenergy technology.
authors.affiliation: Research Group ENVOC, Ghent University, Coupure Links 653, B-9000 Ghent, Belgium.
authors.forename: Steven
authors.initials: S
authors.lastname: De Meester
authors.forename: Jens
authors.initials: J
authors.lastname: Demeyer
authors.forename: Filip
authors.initials: F
authors.lastname: Velghe
authors.forename: Andy
authors.initials: A
authors.lastname: Peene
authors.forename: Herman
authors.initials: H
authors.lastname: Van Langenhove
authors.forename: Jo
authors.initials: J
authors.lastname: Dewulf
mesh_terms: D000383:Agriculture / Q000379:methods; D001421:Bacteria, Anaerobic / Q000378:metabolism*; D001530:Belgium; D001674:Bioelectric Energy Sources / Q000009:adverse effects / Q000191:economics / Q000592:standards*; D018533:Biomass; D019149:Bioreactors; D004777:Environment; D005308:Fertilizers / Q000032:analysis / Q000191:economics; D005858:Germany; D059205:Renewable Energy / Q000191:economics / Q000706:statistics & numerical data*
chemical_list: D005308:Fertilizers