| 81. |
- Pettersson, Malin, et al.
(författare)
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Reductions in greenhouse gas emissions through innovative co-production of bio-oil in combined heat and power plants
- 2022
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619. ; 324
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Tidskriftsartikel (refereegranskat)abstract
- Integrating fast pyrolysis into existing biomass-based combined heat and power (CHP) plants offers an innovative opportunity for plant operators to acquire an additional heat sink and produce a renewable transport fuels feedstock. This technology is particularly interesting in Sweden, where biobased heat and power constitute an important part of the energy system. It is important to establish the GHG emissions reduction of the production, through e.g. substitution effects in the transport sector, to ensure coherence with climate ambitions. In this study, the GHG emission avoidance methodology in the newly introduced EU Innovation Fund (IF) was adapted to determine whether integrating bio-oil production into an existing wood-fuelled CHP plant through fast pyrolysis would lead to a significant reduction in GHG emissions compared to the status quo. The results showed a reduction in GHG emissions of up to 0.24 MtCO2-eq per year, due mainly to the replacement of fossil fuels in the transport sector. A potential production volume in existing Swedish CHP plants was estimated to be 6.8–8.1 Mt of bio-oil annually, leading to a GHG emission avoidance of 8.6–10.3 MtCO2-eq/y, requiring a wood fuel input of 181–185 PJ/y. Sensitivity analysis indicated a significant potential for the reduction using input parameters for heating, electricity and hydrogen production whether pre-defined in the IF methodology or determined from case-specific conditions. However, the detailed results indicate that case-specific conditions should be used to reflect the fact that different European countries are at different stages in the transition to a fossil-free energy system. In conclusion, according to IF-based calculations, commercialisation of combined heat, power and bio-oil technology could lead to significant GHG emission avoidance across multiple sectors.
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| 82. |
- 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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| 83. |
- Prade, Thomas, et al.
(författare)
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EU sustainability criteria for biofuels potentially restrict ley crop production on marginal land for use as biogas substrate
- 2013
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Ingår i: Grassland Science in Europe. ; 18, s. 528-530
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Konferensbidrag (refereegranskat)abstract
- Ley crops can be grown to provide a substrate for biogas vehicle-fuel production on a range of soils including marginal land. According to EU regulations, such biofuel currently has to achieve an emission reduction of 35%, but tightened goals of 50 and 60% will come into effect as early as 2017. In two field trials (one on marginal soil, one on productive soil) ley crop mixtures were tested and the biomass DM yield was determined. In a life-cycle assessment approach, the emissions of the production chain for biogas-vehicle-fuel were estimated for a range of biomass DM yields. The results show that the emission intensity per energy unit of fuel produced is an asymptotic function of the DM yield. Currently, marginal lands not competing with food production can provide biofuels fulfilling the emission reduction requirements. However, a tightening of the goals to 50 or 60% is likely to cause a shift in biomass production towards better soils, potentially causing competition with food and feed production. Alternatively, the CO2 emissions from biomass production of marginal soils need to be further reduced, e.g. by increased nitrogen fixation or reduced machinery use.
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| 84. |
- 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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| 85. |
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| 86. |
- Prade, Thomas, et al.
(författare)
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Introduction of grass-clover crops as biogas feedstock in cereal dominated crop rotations. Part I: Effects on soil organic carbon and food production
- 2014
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Ingår i: Proceedings of the 9th International Conference on Life Cycle Assessment in the Agri-Food Sector. - 9780988214576 ; , s. 1032-1040
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Konferensbidrag (refereegranskat)abstract
- Changes of soil organic carbon (SOC) ontent can have a substantial effect on greenhouse gas emissions, but are rarely included in cropproduction LCAs. SOC content strongly influences soil fertility and therefore crop yields, but is declining in many European soils. The present study investigated if integration of 1-2 years of grass-clover crops in a cereal-dominated crop rotation can increase the SOC pool and how this would impact food production. Results show that when grass-clover crops are integrated, the potential SOC content at steady state will be 41 to 52% higher than in the conventional cereal-dominated crop rotation. The net increase of wheat yields based on SOC improvements indicate that for a crop rotation with one year of grass-clover crops, the initial loss of food production can be counterbalanced due to the impact on fertility of the SOC increase.
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| 87. |
- Prade, Thomas, et al.
(författare)
-
Sustainable Cereal Straw Management: Use as Feedstock for Emerging Biobased Industries or Cropland Soil Incorporation?
- 2021
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Ingår i: Waste and Biomass Valorization. - : Springer Science and Business Media LLC. - 1877-2641 .- 1877-265X. ; 12, s. 5649-5663
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Tidskriftsartikel (refereegranskat)abstract
- Sustainability goals regarding biobased chemicals and fuels can lead to increased demand for cereal straw, which could lead to undesirable effects on soil organic matter (SOM) content. The aim of this study was to evaluate the effects of removing straw on SOM, using a life cycle approach based on agricultural statistics and soil carbon modelling. This regional evaluation in southern Sweden showed that the general restrictions on straw removal recommended in many European studies, with demands on the incorporation of at least half of the aboveground straw, is not an efficient means of SOM preservation. Unrestricted straw removal in combination with the cultivation of intermediate crops leads to a much higher SOM build-up. Such measures will increase the availability of removable straw 2.5 times, at little extra cost. The findings of this study demonstrate the necessity of regional evaluation, taking new findings on the impact of straw incorporation on SOM into consideration. This is important for both regional emerging biobased industries, where unnecessary restrictions on straw removal might hamper the development of new production pathways, and for future sustainability in agriculture, where well-intended but inefficient SOM preservation strategies might hinder the implementation of more efficient measures.[GRAPHICS].
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| 88. |
- Selling, Robert, et al.
(författare)
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Two-stage anaerobic digestion enables heavy metal removal.
- 2008
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Ingår i: Water Science and Technology. - : IWA Publishing. - 0273-1223 .- 1996-9732. ; 57:4, s. 553-558
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Tidskriftsartikel (refereegranskat)abstract
- To fully exploit the environmental benefits of the biogas process, the digestate should be recycled as biofertiliser to agriculture. This practice can however be jeopardized by the presence of unwanted compounds such as heavy metals in the digestate. By using two-stage digestion, where the first stage includes hydrolysis/acidification and liquefaction of the substrate, heavy metals can be transferred to the leachate. From the leachate, metals can then be removed by adsorption. In this study, up to 70% of the Ni, 40% of the Zn and 25% of the Cd present in maize was removed when the leachate from hydrolysis was circulated over a macroporous polyacrylamide column for 6 days. For Cu and Pb, the mobilization in the hydrolytic stage was lower which resulted in a low removal. A more efficient two-stage process with improved substrate hydrolysis would give lower pH and/or longer periods with low pH in the hydrolytic stage. This is likely to increase metal mobilisation, and would open up for an excellent opportunity of heavy metal removal.
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| 89. |
- Sipos, Balint, et al.
(författare)
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Steam pretreatment of dry and ensiled industrial hemp for ethanol production
- 2010
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Ingår i: Biomass & Bioenergy. - : Elsevier BV. - 1873-2909 .- 0961-9534. ; 34:12, s. 1721-1731
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Tidskriftsartikel (refereegranskat)abstract
- Biomass can be converted into liquid and gaseous biofuels with good efficiency. In this study, the conversion of industrial hemp (Cannabis sativa L.), a biomass source that can be cultivated with a high biomass yield per hectare, was used. Steam pretreatment of dry and ensiled hemp was investigated prior to ethanol production. The pretreatment efficiency was evaluated in terms of sugar recovery and polysaccharide conversion in the enzymatic hydrolysis step. For both materials, impregnation with 2% SO2 followed by steam pretreatment at 210 degrees C for 5 min were found to be the optimal conditions leading to the highest overall yield of glucose. Simultaneous saccharification and fermentation experiments carried out with optimised pretreatment conditions resulted in ethanol yields of 163 g kg(-1) ensiled hemp (dry matter) (71% of the theoretical maximum) and 171 g kg(-1) dry hemp (74%), which corresponds to 206-216 l Mg-1 ethanol based on initial dry material. (C) 2010 Elsevier Ltd. All rights reserved.
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| 90. |
- Svensson, L M, et al.
(författare)
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Biogas production from crop residues on a farm-scale level in Sweden: scale, choice of substrate and utilisation rate most important parameters for financial feasibility
- 2006
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Ingår i: Bioprocess and Biosystems Engineering. - : Springer Science and Business Media LLC. - 1615-7605 .- 1615-7591. ; 29:2, s. 137-142
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Tidskriftsartikel (refereegranskat)abstract
- Anaerobic digestion would enable the energy potential of agricultural crop residues such as ley crops and sugar beet tops to be harnessed in Sweden. In the present study, the financial prospects of single-stage fed-batch high-solids digestion on three different scales, 51, 67, and 201 kW, were calculated on the basis of experimental results and observations. In addition to scale, the effects of methane yield and fertiliser recovery (compared to green manuring) was investigated by testing different substrate mixtures. The biogas was disposed as heat, combined heat and power, or as vehicle fuel. Besides the positive effect of scale, the results indicate the importance of choosing substrates with a high methane yield and high nitrogen content, and the necessity of fully utilising both the capacity of the equipment installed and the energy carriers produced. Net unit costs of 5.3 and 8.1 Euroct/kWh were achieved (201 kW), heat and vehicle fuel, respectively.
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