Sie können Bookmarks mittels Listen verwalten, loggen Sie sich dafür bitte in Ihr SLUB Benutzerkonto ein.
Medientyp:
E-Artikel
Titel:
Cattle feed or bioenergy? Consequential life cycle assessment of biogas feedstock options on dairy farms
Beteiligte:
Styles, David;
Gibbons, James;
Williams, Arwel Prysor;
Stichnothe, Heinz;
Chadwick, David Robert;
Healey, John Robert
Erschienen:
Wiley, 2015
Erschienen in:GCB Bioenergy
Sprache:
Englisch
DOI:
10.1111/gcbb.12189
ISSN:
1757-1693;
1757-1707
Entstehung:
Anmerkungen:
Beschreibung:
<jats:title>Abstract</jats:title><jats:p>On‐farm anaerobic digestion (<jats:styled-content style="fixed-case">AD</jats:styled-content>) of wastes and crops can potentially avoid greenhouse gas (<jats:styled-content style="fixed-case">GHG</jats:styled-content>) emissions, but incurs extensive environmental effects via carbon and nitrogen cycles and substitution of multiple processes within and outside farm system boundaries. Farm models were combined with consequential life cycle assessment (<jats:styled-content style="fixed-case">CLCA</jats:styled-content>) to assess plausible biogas and miscanthus heating pellet scenarios on dairy farms. On the large dairy farm, the introduction of slurry‐only <jats:styled-content style="fixed-case">AD</jats:styled-content> led to reductions in global warming potential (<jats:styled-content style="fixed-case">GWP</jats:styled-content>) and resource depletion burdens of 14% and 67%, respectively, but eutrophication and acidification burden increases of 9% and 10%, respectively, assuming open tank digestate storage. Marginal <jats:styled-content style="fixed-case">GWP</jats:styled-content> burdens per Mg dry matter (<jats:styled-content style="fixed-case">DM</jats:styled-content>) feedstock codigested with slurry ranged from –637 kg <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub>e for food waste to +509 kg <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub>e for maize. Codigestion of grass and maize led to increased imports of concentrate feed to the farm, negating the <jats:styled-content style="fixed-case">GWP</jats:styled-content> benefits of grid electricity substitution. Attributing grass‐to‐arable land use change (<jats:styled-content style="fixed-case">LUC</jats:styled-content>) to marginal wheat feed production led to net <jats:styled-content style="fixed-case">GWP</jats:styled-content> burdens exceeding 900 kg <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub>e Mg<jats:sup>−1</jats:sup> maize <jats:styled-content style="fixed-case">DM</jats:styled-content> codigested. Converting the medium‐sized dairy farm to a beef‐plus‐<jats:styled-content style="fixed-case">AD</jats:styled-content> farm led to a minor reduction in <jats:styled-content style="fixed-case">GWP</jats:styled-content> when grass‐to‐arable <jats:styled-content style="fixed-case">LUC</jats:styled-content> was excluded, but a 38% <jats:styled-content style="fixed-case">GWP</jats:styled-content> increase when such <jats:styled-content style="fixed-case">LUC</jats:styled-content> was attributed to marginal maize and wheat feed required for intensive compensatory milk production. If marginal animal feed is derived from soybeans cultivated on recently converted cropland in South America, the net <jats:styled-content style="fixed-case">GWP</jats:styled-content> burden increases to 4099 kg <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub>e Mg<jats:sup>−1</jats:sup> maize <jats:styled-content style="fixed-case">DM</jats:styled-content> codigested – equivalent to 55 Mg <jats:styled-content style="fixed-case">CO</jats:styled-content><jats:sub>2</jats:sub>e yr<jats:sup>−1</jats:sup> per hectare used for <jats:styled-content style="fixed-case">AD</jats:styled-content>‐maize cultivation. We conclude that <jats:styled-content style="fixed-case">AD</jats:styled-content> of slurry and food waste on dairy farms is an effective <jats:styled-content style="fixed-case">GHG</jats:styled-content> mitigation option, but that the quantity of codigested crops should be strictly limited to avoid potentially large international carbon leakage via animal feed displacement.</jats:p>