Greenhouse gas emissions from cultivation of energy crops may affect the sustainability of biofuels

Henrik Hauggaard-Nielsen, Mette Sustmann Carter, Stefan Heiske, Sune Tjalfe Thomsen, Morten Jensen, Jens Ejbye Schmidt, Anders Johansen, Per Ambus

Publikation: Bidrag til bog/antologi/rapportKonferenceabstrakt i proceedingsForskningpeer review

Resumé

Agro-biofuels are expected to reduce the emissions of greenhouse gases because CO2 emitted during the combustion of the biofuels has recently been taken from the atmosphere by the energy crop. Thus, when replacing fossil fuels with biofuels we reduce the emission of fossil fuel-derived CO2 into the atmosphere. However, cultivation of the soil results in emission of other greenhouse gasses, especially nitrous oxide (N2O). Agricultural activity is the dominant source of N2O, which is produced by microbes in the soil when the nitrogen availability is high, for instance following fertilization or incorporation of crop residues. In this study we relate measured field emissions of N2O to the reduction in fossil fuel-derived CO2, which is obtained when energy crops are used for biofuel production. The analysis includes five organically managed crops (viz. maize, rye, rye-vetch, vetch and grass-clover) and three scenarios for conversion of biomass to biofuel. The scenarios are 1) bioethanol production, 2) biogas production and 3) co-production of bioethanol and biogas, where the energy crops are first used for bioethanol fermentation and subsequently the residues from this process are utilized for biogas production. The net reduction in greenhouse gas emissions is calculated as the avoided fossil fuel-derived CO2, where the N2O emission has been subtracted. This value does not include farm machinery CO2 emissions and fuel consumption during biofuel production. Thus, the actual net greenhouse gas reduction will be lower than indicated by our data. We obtained the greatest net reduction in greenhouse gas emissions by co-production of bioethanol and biogas or by biogas alone produced from either fresh grass-clover or whole crop maize. Here the net reduction corresponded to about 8 tons CO2 per hectare per year. The worst result was obtained for bioethanol produced from vetch straw where high N2O emissions outweighed the avoided fossil fuel-derived CO2.
OriginalsprogEngelsk
TitelEnergy Systems and Technologies for the coming Century : proceedings
Udgivelses stedRoskilde
ForlagDanmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi
Publikationsdato2011
Sider283-283
ISBN (Trykt)978-87-550-3903-2
StatusUdgivet - 2011
Udgivet eksterntJa
BegivenhedRisø International Energy Conference 2011 - Forskningscenter Risoe, Roskilde, Danmark
Varighed: 10 maj 201112 maj 2011

Konference

KonferenceRisø International Energy Conference 2011
LokationForskningscenter Risoe
LandDanmark
ByRoskilde
Periode10/05/201112/05/2011
NavnDenmark. Forskningscenter Risoe. Risoe-R
Nummer1776(EN)
ISSN0106-2840

Citer dette

Hauggaard-Nielsen, H., Carter, M. S., Heiske, S., Thomsen, S. T., Jensen, M., Schmidt, J. E., ... Ambus, P. (2011). Greenhouse gas emissions from cultivation of energy crops may affect the sustainability of biofuels. I Energy Systems and Technologies for the coming Century : proceedings (s. 283-283). Roskilde: Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi. Denmark. Forskningscenter Risoe. Risoe-R, Nr. 1776(EN)
Hauggaard-Nielsen, Henrik ; Carter, Mette Sustmann ; Heiske, Stefan ; Thomsen, Sune Tjalfe ; Jensen, Morten ; Schmidt, Jens Ejbye ; Johansen, Anders ; Ambus, Per. / Greenhouse gas emissions from cultivation of energy crops may affect the sustainability of biofuels. Energy Systems and Technologies for the coming Century : proceedings. Roskilde : Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi, 2011. s. 283-283 (Denmark. Forskningscenter Risoe. Risoe-R; Nr. 1776(EN)).
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Hauggaard-Nielsen, H, Carter, MS, Heiske, S, Thomsen, ST, Jensen, M, Schmidt, JE, Johansen, A & Ambus, P 2011, Greenhouse gas emissions from cultivation of energy crops may affect the sustainability of biofuels. i Energy Systems and Technologies for the coming Century : proceedings. Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi, Roskilde, Denmark. Forskningscenter Risoe. Risoe-R, nr. 1776(EN), s. 283-283, Risø International Energy Conference 2011, Roskilde, Danmark, 10/05/2011.

Greenhouse gas emissions from cultivation of energy crops may affect the sustainability of biofuels. / Hauggaard-Nielsen, Henrik; Carter, Mette Sustmann; Heiske, Stefan; Thomsen, Sune Tjalfe; Jensen, Morten ; Schmidt, Jens Ejbye; Johansen, Anders; Ambus, Per.

Energy Systems and Technologies for the coming Century : proceedings. Roskilde : Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi, 2011. s. 283-283 (Denmark. Forskningscenter Risoe. Risoe-R; Nr. 1776(EN)).

Publikation: Bidrag til bog/antologi/rapportKonferenceabstrakt i proceedingsForskningpeer review

TY - ABST

T1 - Greenhouse gas emissions from cultivation of energy crops may affect the sustainability of biofuels

AU - Hauggaard-Nielsen, Henrik

AU - Carter, Mette Sustmann

AU - Heiske, Stefan

AU - Thomsen, Sune Tjalfe

AU - Jensen, Morten

AU - Schmidt, Jens Ejbye

AU - Johansen, Anders

AU - Ambus, Per

PY - 2011

Y1 - 2011

N2 - Agro-biofuels are expected to reduce the emissions of greenhouse gases because CO2 emitted during the combustion of the biofuels has recently been taken from the atmosphere by the energy crop. Thus, when replacing fossil fuels with biofuels we reduce the emission of fossil fuel-derived CO2 into the atmosphere. However, cultivation of the soil results in emission of other greenhouse gasses, especially nitrous oxide (N2O). Agricultural activity is the dominant source of N2O, which is produced by microbes in the soil when the nitrogen availability is high, for instance following fertilization or incorporation of crop residues. In this study we relate measured field emissions of N2O to the reduction in fossil fuel-derived CO2, which is obtained when energy crops are used for biofuel production. The analysis includes five organically managed crops (viz. maize, rye, rye-vetch, vetch and grass-clover) and three scenarios for conversion of biomass to biofuel. The scenarios are 1) bioethanol production, 2) biogas production and 3) co-production of bioethanol and biogas, where the energy crops are first used for bioethanol fermentation and subsequently the residues from this process are utilized for biogas production. The net reduction in greenhouse gas emissions is calculated as the avoided fossil fuel-derived CO2, where the N2O emission has been subtracted. This value does not include farm machinery CO2 emissions and fuel consumption during biofuel production. Thus, the actual net greenhouse gas reduction will be lower than indicated by our data. We obtained the greatest net reduction in greenhouse gas emissions by co-production of bioethanol and biogas or by biogas alone produced from either fresh grass-clover or whole crop maize. Here the net reduction corresponded to about 8 tons CO2 per hectare per year. The worst result was obtained for bioethanol produced from vetch straw where high N2O emissions outweighed the avoided fossil fuel-derived CO2.

AB - Agro-biofuels are expected to reduce the emissions of greenhouse gases because CO2 emitted during the combustion of the biofuels has recently been taken from the atmosphere by the energy crop. Thus, when replacing fossil fuels with biofuels we reduce the emission of fossil fuel-derived CO2 into the atmosphere. However, cultivation of the soil results in emission of other greenhouse gasses, especially nitrous oxide (N2O). Agricultural activity is the dominant source of N2O, which is produced by microbes in the soil when the nitrogen availability is high, for instance following fertilization or incorporation of crop residues. In this study we relate measured field emissions of N2O to the reduction in fossil fuel-derived CO2, which is obtained when energy crops are used for biofuel production. The analysis includes five organically managed crops (viz. maize, rye, rye-vetch, vetch and grass-clover) and three scenarios for conversion of biomass to biofuel. The scenarios are 1) bioethanol production, 2) biogas production and 3) co-production of bioethanol and biogas, where the energy crops are first used for bioethanol fermentation and subsequently the residues from this process are utilized for biogas production. The net reduction in greenhouse gas emissions is calculated as the avoided fossil fuel-derived CO2, where the N2O emission has been subtracted. This value does not include farm machinery CO2 emissions and fuel consumption during biofuel production. Thus, the actual net greenhouse gas reduction will be lower than indicated by our data. We obtained the greatest net reduction in greenhouse gas emissions by co-production of bioethanol and biogas or by biogas alone produced from either fresh grass-clover or whole crop maize. Here the net reduction corresponded to about 8 tons CO2 per hectare per year. The worst result was obtained for bioethanol produced from vetch straw where high N2O emissions outweighed the avoided fossil fuel-derived CO2.

KW - Environment and climate

KW - Risø-R-1776

KW - Risø-R-1776(EN)

M3 - Conference abstract in proceedings

SN - 978-87-550-3903-2

SP - 283

EP - 283

BT - Energy Systems and Technologies for the coming Century

PB - Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi

CY - Roskilde

ER -

Hauggaard-Nielsen H, Carter MS, Heiske S, Thomsen ST, Jensen M, Schmidt JE et al. Greenhouse gas emissions from cultivation of energy crops may affect the sustainability of biofuels. I Energy Systems and Technologies for the coming Century : proceedings. Roskilde: Danmarks Tekniske Universitet, Risø Nationallaboratoriet for Bæredygtig Energi. 2011. s. 283-283. (Denmark. Forskningscenter Risoe. Risoe-R; Nr. 1776(EN)).