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| 2. |
- Prade, Thomas, et al.
(författare)
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Including a one-year grass ley increases soil organic carbon and decreases greenhouse gas emissions from cereal-dominated rotations – A Swedish farm case study
- 2017
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Ingår i: Biosystems Engineering. - : Elsevier BV. - 1537-5110 .- 1537-5129. ; 164, s. 200-212
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Tidskriftsartikel (refereegranskat)abstract
- Increased soil organic carbon (SOC) content has been shown to increase soil fertility and carbon sequestration, but SOC changes are frequently neglected in life cycle assessment (LCA) studies of crop production. This study used a novel LCA application using simulated SOC changes to examine the greenhouse gas (GHG) impact of a combined food and energy crop production from a crop rotation perspective. On a case pig farm, introduction of one year of grass ley into a cereal-dominated crop rotation was simulated. The grass and pig manure were used for biogas production and the digestion residues were used as fertiliser on the farm. This crop rotation shift increased the SOC stocks by an estimated 27 and 49% after 50 years and at steady state, respectively. The estimated corresponding net wheat yield increase due to higher SOC was 8–16% and 16–32%, respectively, indicating that initial loss of low-yield oat production can be partly counterbalanced. Net SOC increase (corresponding to 2 t CO2-eq ha−1 a−1) was the single most important variable affecting the GHG balance. When biogas replaced fossil fuels, GHG emissions of the combined energy-food crop rotation were approx. 3 t CO2-eq ha−1 a−1 lower than for the current food crop rotation. Sensitivity analyses led to variation of only 2–9% in the GHG balance. This study indicates that integrated food and energy crop production can improve SOC content and decrease GHG emissions from cropping systems. It also demonstrates the importance of including SOC changes in crop production-related LCA studies.
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| 3. |
- Ahlgren, Serina, et al.
(författare)
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Biofuels from agricultural biomass – Land use change in Swedish perspective
- 2017
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The Swedish parliament has decided that by 2045, Sweden will not be a net emitter of greenhouse gases. There is also a goal to have a fossil fuel free transport sector by 2030. However, the transport sector is still dominated by fossil fuels and many efforts are needed to lower emissions. Sweden has a relatively high share of biofuels, around 20% of the energy use in domestictransportation. However, almost 90% of these fuels are imported or produced from imported feedstock.In this study it was investigated whether and how the forecast biofuel demand for 2030 (20 TWh) can be met by biofuels produced from domestic feedstock. The scope was narrowed to biomass that does not cause land use change effects, since the European Commission has communicated that useof biofuels based on feedstock which could be used instead for food or feed will not be supported in the future. The reason for this policy decision is that increased biofuel production could stimulate direct land use change (dLUC) or indirect land use change (iLUC), leading to release ofsoil carbon and other greenhouse gases. We found that about 4-10 TWh of biofuels can be produced from iLUC-free agricultural feedstockin Sweden; the range is dependent on the assumed biofuel conversion rate. The raw material studied was (1) agricultural residues, (2) ley produced on previously unused arable land, (3) crops from arable land such as intermediate crops and (4) intensification of ley cultivation.Literature indicates that iLUC-free feedstock from other sectors (forest residues, industrial byproducts and residues, and residues from other parts of society in Sweden, marine feedstock not included) could contribute 8-11 TWh biofuel. In other words, there is good potential to reach the required 20 TWh of biofuels by 2030 based on domestic iLUC-free feedstock. Lowering domesticconsumption of meat and alcoholic beverages and lowering land use for recreational horse keeping could provide additional space for biofuel production.However, steering towards iLUC-free feedstock would mean higher production costs compared to conventional biofuel production. It is therefore of particular interest to study the potential trade-offs between greenhouse gases and economics. The production of ethanol and biogas based on wheatgrain and wheat straw was studied, where wheat grain represented the current production system and wheat straw represented an iLUC-free production system.We conclude that wheat straw-based biofuels do not compete with food production and have lower greenhouse gas emissions than those based on wheat grain, but higher production costs. The reasons for higher production costs are mainly the lower biofuel yield and more expensive pretreatment.In order to enable general conclusions on trade-offs when steering towards iLUC-free feedstock, more case studies are however needed with a larger set of studied feedstocks, biofuels and including other environmental impacts.
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| 4. |
- Björnsson, Lovisa, et al.
(författare)
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Grass biomass as biofuel feedstock –sustainable or not?
- 2017
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Ingår i: European Biomass Conference and Exhibition Proceedings, 25thEUBCE, June 2017. - 2282-5819. - 9788889407172 ; 2017, s. 39-40
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Konferensbidrag (refereegranskat)abstract
- Low carbon input due to increasing specialization, intensification and reduced use of bio-fertilizer, leads to soil organic carbon (SOC) decreases in arable land. This is an emerging problem in Europe in general, where 45% of the EU soils have low and declining SOC content. SOC losses from agricultural soils influence soil fertility, putting food security at risk, and contributes to greenhouse gas (GHG) emissions. An agricultural practice rendering loss of SOC is thus not sustainable in the long term, and measures must be taken to reverse this trend. However, existing policies for agriculture and biofuels address these issues in isolation, SOC impact is not considered when sustainability criteria for biofuels are defined in the EU renewable energy directive (RED). The aim of this study was to illustrate the relevance of SOC impact on integrated production of food and grass as energy crop for biofuel production. This diversification of current cereal dominated crop rotations proved an efficient tool to reverse SOC losses, simultaneously producing a grass-based biofuel with low climate impact. Since SOC-related aspects are excluded in EU RED, the GHG reduction calculated according to the directive does, however, not meet the 60% GHG reduction demand. This narrow perspective causes potentially interesting double benefits to be missed.
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| 6. |
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| 7. |
- Lantz, Mikael, et al.
(författare)
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An economic comparison of dedicated crops vs agricultural residues as feedstock for biogas of vehicle fuel quality
- 2017
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Ingår i: AIMS Energy. - : American Institute of Mathematical Sciences (AIMS). - 2333-8326 .- 2333-8334. ; 5:5, s. 838-863
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Tidskriftsartikel (refereegranskat)abstract
- The vast majority of the biofuels presently used in the EU are so called first generation biofuels produced from crops. Concerns of food security, displacement of food crop production and indirect land use change (iLUC) has led to the introduction of measures to reduce the use of first generations biofuels and promote so called advanced biofuels based on feedstock that does not compete with food/feed crops, such as waste and agricultural residues. In Sweden, 60% of the biofuel consumption is already based on waste/residual feedstock, and a unique feature of the Swedish biofuel supply is the relatively large use of biogas for transport, representing 9% of the current use of biofuels. The use of waste/residues dominates the biogas production, but agricultural residues, representing a large domestic feedstock potential, are barely used at present. This could indicate that biofuels from such feedstock is non-competitive compared both to fossil fuels and to biofuels produced from crops and waste under existing policy framework. This study show that without subsidies, the production cost of biogas as biofuel from all non-food feedstocks investigated (grass, crop residues and manure) is higher than from food crops. A shift from food crops to residues, as desired according to EU directives, would thus require additional policy instruments favoring advanced biofuel feedstock. Investment or production subsidies must however be substantial in order for biogas from residues to be competitive with biogas from crops.
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| 8. |
- Lantz, Mikael, et al.
(författare)
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Biogas and ethanol from wheat grain or straw : Is there a trade-off between climate impact, avoidance of iLUC and production cost?
- 2018
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 11:10
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Tidskriftsartikel (refereegranskat)abstract
- Current EU policy calls for decreased emissions of greenhouse gases (GHG) by i.e., replacing fossil fuel in the transportation sector with sustainable biofuels. To avoid indirect land use change (iLUC), the EU at the same time strives to limit the use of crops and to increase the use of residues. In this study we compare climate impact and production cost for biogas and ethanol based on wheat grain and straw, respectively, in a Swedish context. The economic competitiveness for ethanol from straw vs. grain is evaluated based on the mandatory emission reduction for fossil vehicle fuels implemented since July 2018 in Sweden. The result of this study clearly shows that biogas and ethanol from straw have the lowest GHG emissions regardless of the calculation method used, although biofuels from grain also fulfill EU GHG reduction criteria even when suggested iLUC factors are included. It was also shown that the cost of producing straw-based biofuels was higher, thus there is a trade-off between climate impact and costs. The GHG reduction mandate adopted in Sweden partly compensates for this, but is not enough to make ethanol from straw competitive from an economic perspective.
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| 9. |
- Prade, Thomas, et al.
(författare)
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Can domestic production of iLUC-free feedstock from arable land supply Sweden’s future demand for biofuels?
- 2017
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Ingår i: Journal of Land Use Science. - 1747-423X .- 1747-4248. ; 12:6, s. 407-441
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Tidskriftsartikel (refereegranskat)abstract
- The increasing biofuel production from agricultural crops has been suggested to cause indirect land use change (iLUC). This increases interest in biofuel feedstocks that qualify as iLUC-free: (1) residues without a market, (2) crops from previously unused arable land, (3) additional crops and (4) biomass from intensified production. In the present study, biofuel potential from such feedstocks was quantified for Sweden and compared against the predicted biofuel demand from agricultural resources in 2030. The results indicate that straw (category 1) could cover up to 37% of future biofuel demand. Grass leys from intensified production (category 4), set-aside and abandoned land (category 2) and excess grass silage (category 1) could cover up to 79%. Intermediate and ecological focus area crops (category 3) could contribute up to 21%. To realize the biofuel targets, a high implementation rate of additional iLUC-free feedstock is needed. Future studies need to investigate impacts of low-iLUC policies.
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