title: The potential for biomethane from grass and slurry to satisfy renewable energy targets.
abstract: A biomethane potential (BMP) assessment of grass silage yielded 107 m(3)CH4 t(-1). Long term mono-digestion of grass silage can suffer due to a deficiency in essential nutrients; this may be overcome by co-digesting with slurry. Mono-digestion of slurry achieved a low yield of 16 m(3)CH4 t(-1). BMP assessments at a range of co-digestion ratios indicated methane yields were between 4% and 11% lower than the values calculated from mono-digestion. This paper suggests that co-digestion of the majority of slurry produced from dairy cows in Ireland with grass silage quantities equivalent to 1.1% of grassland on a 50:50 volatile solids basis would generate over 10% renewable energy supply in transport (RES-T). The industry proposed would equate to 170 digesters each treating 10,000 t a(-1) of grass silage and 40,000 t a(-1) of slurry from dairy cows.
authors.affiliation: Bioenergy and Biofuels Research Group, Environmental Research Institute, University College Cork, Cork, Ireland; School of Engineering, University College Cork, Cork, Ireland; Animal & Grassland Research and Innovation Centre, Teagasc, Grange, Dunsany, Co. Meath, Ireland.
authors.forename: David M
authors.initials: DM
authors.lastname: Wall
authors.forename: Padraig
authors.initials: P
authors.lastname: O'Kiely
authors.forename: Jerry D
authors.initials: JD
authors.lastname: Murphy
mesh_terms: D056804:Biofuels / Q000032:analysis*; D007700:Kinetics; D008697:Methane / Q000378:metabolism*; D006109:Poaceae / Q000378:metabolism*; D059205:Renewable Energy; D012820:Silage / Q000032:analysis*
chemical_list: D056804:Biofuels; D008697:Methane
keywords: BMP; Biogas; Gaseous biofuel; Grass silage; Slurry