| 1. |
- Ahlgren, Serina, et al.
(författare)
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Review of methodological choices in LCA of biorefinery systems - key issues and recommendations
- 2015
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Ingår i: Biofuels, Bioproducts and Biorefining. - : Wiley. - 1932-1031 .- 1932-104X. ; 9:5, s. 606-619
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Forskningsöversikt (refereegranskat)abstract
- The current trend in biomass conversion technologies is toward more efficient utilization of biomass feedstock in multiproduct biorefineries. Many life-cycle assessment (LCA) studies of biorefinery systems have been performed but differ in how they use the LCA methodology. Based on a review of existing LCA standards and guidelines, this paper provides recommendations on how to handle key methodological issues when performing LCA studies of biorefinery systems. Six key issues were identified: (i) goal definition, (ii) functional unit, (iii) allocation of biorefinery outputs, (iv) allocation of biomass feedstock, (v) land use, and (vi) biogenic carbon and timing of emissions. Many of the standards and guidelines reviewed here provide only general methodological recommendations. Some make more specific methodological recommendations, but these often differ between standards. In this paper we present some clarifications (e.g. examples of research questions and suitable functional units) and methodological recommendations (e.g. on allocation).
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| 2. |
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| 3. |
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| 4. |
- Berndes, Göran, 1966, et al.
(författare)
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Bioenergy and Land Use Change-State of the Art
- 2015
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Ingår i: Advances in Bioenergy: The Sustainability Challenge. - Oxford, UK : John Wiley & Sons, Ltd. - 9781118957875 - 9781118957844 ; , s. 249-271
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Bokkapitel (refereegranskat)abstract
- The dedicated production of biomass crops and the collection of residues in agriculture and forestry can lead to undesirable negative impacts and it is crucial that practices are found that ensure that these impacts are avoided or mitigated as far as possible. This chapter concerns the use of biomass for energy and the connection between increased bioenergy use and land use change (LUC). Land use and LUC associated with bioenergy can lead to a multitude of environmental and socioeconomic consequences. The chapter focuses on the question whether greenhouse gas (GHG) emissions associated with LUC could undermine the climate change mitigation benefits of bioenergy. There are, however, several options for mitigating these emissions that can be implemented: development of bioenergy feedstock production systems that integrate with existing agriculture and forestry production, enhancement of land use productivity in agriculture and forestry in general, and legal protection of natural ecosystems.
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| 5. |
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| 6. |
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| 7. |
- Börjesson, Pål, et al.
(författare)
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Energy Crop-Based Biogas as Vehicle Fuel: The Impact of Crop Selection on Energy Efficiency and Greenhouse Gas Performance
- 2015
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Ingår i: Energies. - : MDPI AG. - 1996-1073. ; 8:6, s. 6033-6058
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Tidskriftsartikel (refereegranskat)abstract
- The production of biogas from six agricultural crops was analysed regarding energy efficiency and greenhouse gas (GHG) performance for vehicle fuel from a field-to-tank perspective, with focus on critical parameters and on calculation methods. The energy efficiency varied from 35% to 44%, expressed as primary energy input per energy unit vehicle gas produced. The GHG reduction varied from 70% to 120%, compared with fossil liquid fuels, when the GHG credit of the digestate produced was included through system expansion according to the calculation methodology in the ISO 14044 standard of life cycle assessment. Ley crop-based biogas systems led to the highest GHG reduction, due to the significant soil carbon accumulation, followed by maize, wheat, hemp, triticale and sugar beet. Critical parameters are biogenic nitrous oxide emissions from crop cultivation, for which specific emission factors for digestate are missing today, and methane leakage from biogas production. The GHG benefits were reduced and the interrelation between the crops changed, when the GHG calculations were instead based on the methodology stated in the EU Renewable Energy Directive, where crop contribution to soil carbon accumulation is disregarded. All systems could still reach a 60% GHG reduction, due to the improved agricultural management when digestate replaces mineral fertilisers.
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| 8. |
- Börjesson, Pål, et al.
(författare)
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Future demand for forest-based biomass for energy purposes in Sweden
- 2017
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383:January, s. 17-26
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Tidskriftsartikel (refereegranskat)abstract
- This paper assesses the potential changes in the demand for forest-based biomass for various energy purposes in Sweden in 2030 and 2050, respectively. The assessment is based on a review of scenarios and predictions of how the Swedish energy system may develop, taking into account techno-economical conditions. It includes potential changes in district heating, electricity production in combined heat and power plants, industrial process energy, and production of biofuel for road transportation. In addition, the potential demand for forest-based feedstock in the chemical and petrochemical sector, replacing current use of fossil feedstock, is analysed. The assessment suggests that Sweden may see an additional demand for forest fuels at about 30 TW h in 2030 and 35–40 TW h in 2050. This can be compared with the current use of biomass for energy in Sweden at 130 TW h per year, and the estimated potential increase of sustainable harvest of logging residues (slash and stumps) at some additional 20 TW h per year, based on current conditions. If also potential demand for forest-based feedstock in the chemical and petrochemical industry is included, another 10–15 and 25–30 TW h of biomass per year may be needed in 2030 and 2050, respectively. The future demand is sensitive to the pace and magnitude of energy efficiency improvements and electrification in the various sectors. If far-reaching energy efficiency improvements and electrification are realised, the total additional demand for biomass as energy and industry feedstock may be about 20 and 30 TW h per year in 2030 and 2050, respectively, thus roughly corresponding to the sustainable harvests of logging residues. If, however, efficiency improvements and electrification are only marginal, then the additional demand for biomass as industry and energy feedstock may reach 70 TW h and 100 TW h per year in 2030 and 2050, respectively. In these cases, the use of logging residues will not suffice and additional biomass would be needed. A combination of regulations and incentives is recommended to accelerate the fuel and feedstock switch, especially in the transportation and industrial sectors, and incentives promoting a substantial improvement in energy efficiency and electrification in all sectors.
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| 9. |
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| 10. |
- Börjesson, Pål
(författare)
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Potential för ökad tillförsel och avsättning av inhemsk biomassa i en växande svensk bioekonomi
- 2016
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- I denna studie analyseras potentialen för en ökad tillförsel av biomassa från skog, jordbruk och akvatiska system i Sverige baserat på en sammanställning och bearbetning av aktuella potentialstudier. Analysen inkluderar tekno-ekonomiska begränsningar och minimering av risker för miljömålskonflikter vid en ökad produktion av biomassa. Dessutom analyseras potentialen för en ökad avsättning av biomassa för att ersätta fossil energi och råvara inom olika sektorer. Tidsperspektivet sträcker sig från idag till 2050. Resultaten visar att det finns en relativt god balans mellan de uppskattade ökade tillförsel- och avsättningspotentialerna inom tidsperspektivet idag till 2030 och att dessa uppgår till cirka 40-50 TWh biomassa per år. Kring 2050 bedöms tillförselpotentialen kunna öka till cirka 70-90 TWh per år medan avsättningspotentialen bedöms kunna öka till cirka 60-70 TWh per år. Tillförseln av skogsbaserad biomassa är något högre än jordbruksbaserad medan akvatisk biomassa bedöms bli marginell. Det finns dock ett stort osäkerhetsintervall både vad gäller ökad tillförselpotential och avsättningspotential, d v s beroende på vilka utvecklingsvägar som väljs kan teoretiskt såväl betydande underskott som överskott av biomassa fås. För att minimera risker för miljömålskonflikter krävs långsiktigt uthålliga produktionssystem som bl a har ett ökat landskapsperspektiv, i kombination med åtgärder på användarsidan för att begränsa ökningen av biomassabehovet genom energieffektivisering och elektrifiering inom transport-, industri- och värmesektorn. För att de långsiktigt uthålliga ökade tillförsel- och avsättningspotentialerna ska kunna realiseras krävs skärpta styrmedel och incitament inom alla berörda sektorer.
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| 11. |
- Börjesson, Pål, et al.
(författare)
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The Climate Benefit of Swedish Ethanol : Present and Prospective Performance
- 2015
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Ingår i: Advances in Bioenergy: The Sustainability Challenge. - Oxford, UK : John Wiley & Sons, Ltd. - 9781118957875 - 9781118957844 ; , s. 395-410
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Bokkapitel (refereegranskat)abstract
- This chapter presents an assessment of green house performance (GHG) performance of current and prospective Swedish ethanol production and outlines a strategy for improving the GHG performance on an expanding ethanol market. Calculations are presented that consider process integration and establishment of biocombines producing multiple products, the use of a broader resource base including lignocellulosic feedstocks, and expansion options that minimize GHG emissions from land use changes (LUC) associated with the ethanol production. Based on this, the scenario for Swedish ethanol expansion shows how the production could increase substantially while maintaining a very favorable GHG profile. The chapter applies a broad multidisciplinary systems approach that combines an assessment of critical issues, such as the technical design of ethanol systems, the category of feedstock, the direct land use changes (dLUC), the indirect land use changes (iLUC), treatment of coproducts, and temporal boundaries.
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| 12. |
- Cintas Sanchez, Olivia, 1982, et al.
(författare)
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The potential role of forest management in Swedish scenarios towards climate neutrality by mid century
- 2017
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Ingår i: Forest Ecology and Management. - : Elsevier BV. - 0378-1127 .- 1872-7042. ; 383:January, s. 73-84
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Tidskriftsartikel (refereegranskat)abstract
- Swedish climate policy targets net zero greenhouse gases (GHG) by mid-century, with road transport independent of fossil fuels by 2030, requiring far-reaching changes in the way energy is used. Forest management is expected to support carbon sequestration and provide biomass for various uses, including energy. In this paper, we combine two energy scenarios with four forest scenarios and quantify GHG balances associated with energy-use for heat, electricity, and road transport, and with forest management and production, use, and end-of-life management of various forest products, including products for export. The aggregated GHG balances are evaluated in relation to the 2-degree target and an allocated Swedish CO2 budget. The production of biofuels in the agriculture sector is considered but not analyzed in detail.The results suggest that Swedish forestry can make an important contribution by supplying forest fuels and other products while maintaining or enhancing carbon storage in vegetation, soils, and forest products. The GHG neutrality goal is not met in any of the scenarios without factoring in carbon sequestration. Measures to enhance forest productivity can increase output of forest products (including biofuels for export) and also enhance carbon sequestration. The Swedish forest sector can let Sweden reach net negative emissions, and avoid “using up” its allocated CO2 budget, thereby increasing the associated emissions space for the rest of the world.
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| 13. |
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| 14. |
- Englund, Oskar, et al.
(författare)
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Beneficial land use change : Strategic expansion of new biomass plantations can reduce environmental impacts from EU agriculture
- 2019
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Annan publikation (övrigt vetenskapligt/konstnärligt)abstract
- Society faces the double challenge of addressing negative impacts of current land use, while increasing biomass production to meet the future demands for food, materials and bioenergy. Potential impacts of increasing the biomass supply are subject to debate. In the discourse, land use change (LUC) has often been considered as negative, referring to impacts of deforestation and cropland expansion. At the same time, LUC is considered necessary for mitigating impacts of existing land use. Strategic establishment of suitable crop cultivation systems in agricultural landscapes can mitigate environmental impacts of current crop production, while providing biomass for the bioeconomy. Here, we explore the potential for such “beneficial LUC” in EU28, based on high-resolution land use modeling. First, we map and quantify the degree of accumulated soil organic carbon losses, wind and water erosion, nitrogen emissions to water, and recurring flooding, in ~81.000 individual sub-watersheds in EU28. We then estimate the effectiveness in mitigating these impacts through establishment of perennial plants, in each sub-watershed. Finally, we identify areas where perennialization may be particularly beneficial from an environmental point of view. The results indicate that there is a substantial potential for effective mitigation, regarding all the assessed impacts. Depending on criteria selection, some 10-46% of the land used for annual crop production in EU28 is located in landscapes that could be considered priority areas for beneficial LUC. While some recent policy development is favorable for promoting beneficial LUC, the effectiveness could be increased by seeking synergies between climate change mitigation, energy security, and other societal goals. One way forward can be to identify and promote options for biomass production in the context of SDG implementation.
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| 15. |
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| 16. |
- García González, María Nelly, et al.
(författare)
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Development and Life Cycle Assessment of Polyester Binders Containing 2,5-Furandicarboxylic Acid and Their Polyurethane Coatings
- 2018
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Ingår i: Journal of Polymers and the Environment. - : Springer Science and Business Media LLC. - 1566-2543 .- 1572-8919. ; 26:9, s. 3626-3637
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Tidskriftsartikel (refereegranskat)abstract
- This work presents a new polyester binder based on 2,5-furandicarboxylic acid (FDCA) as precursors of polyurethane (PU) coatings. The new 100% bio-based structure is composed of four different monomers such as glycerine (Gly), 1,3-propanediol (1,3-PD), 2,5-furandicarboxylic acid (FDCA) and succinic acid (SA). The corresponding PU coating was obtained by crosslinking with a conventional polyisocyanate (Vestanat 1890/100). Evaluation of technological performances is present and benchmarked against partially bio-based (75% renewable carbon) polyester binder and fossil-based polyester binder, already developed in one of our previous work. The study showed a stiffer PU coating and a more hydrophilic character leading to better adhesion where a possible potential application may be interesting as an intermediate layer/primer in the field of metal coating (coil coating, automotive). Afterwards, the evaluation of the total impact of greenhouse gas emissions (GHG), the total non-renewable energy use (NREU) by the Life Cycle Assessment (LCA) for the new polyester binder are included on a cradle-to-gate approach, and considering an FDCA production process starting from sugar beet (primary data). The results showed a very noteworthy reduction in terms of GHG emissions (− 36 and − 79%) and a noticeable reduction impact in terms of NREU (− 38 and − 60%) compared to 75% bio-based and fossil-based polyester binders respectively. Moreover, a sensitivity analysis regarding sugar production from beet cultivation was developed through different LCA calculation methodologies. Those methodologies showed a not very significant difference between them.
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| 17. |
- Gustavsson, Christer, 1968-
(författare)
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Added value from biomass by broader utilization of fuels and CHP plants
- 2016
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The present work, where additional value-creating processes in existing combined heat and power (CHP) structures have been examined, is motivated by a political- and consumer-driven strive towards a bioeconomy and a stagnation for the existing business models in large parts of the CHP sector.The research is based on cases where the integration of flash pyrolysis for co-production of bio-oil, co-gasification for production of fuel gas and synthetic biofuels as well as leaching of extractable fuel components in existing CHP plants have been simulated. In particular, this work has focused on the CHP plants that utilize boilers of fluidized bed (FB) type, where the concept of coupling a separate FB reactor to the FB of the boiler forms an important basis for the analyses. In such dual fluidized bed (DFB) technology, heat is transferred from the boiler to the new reactor that is operating with other fluidization media than air, thereby enabling other thermochemical processes than combustion to take place. The result of this work shows that broader operations at existing CHP plants have the potential to enable production of significant volumes of chemicals and/or fuels with high efficiency, while maintaining heat supply to external customers.Based on the insight that the technical preconditions for a broader operation are favourable, the motivation and ability among the incumbents in the Swedish CHP sector to participate in a transition of their operation towards a biorefinery was examined. The result of this assessment showed that the incumbents believe that a broader operation can create significant values for their own operations, the society and the environment, but that they lack both a strong motivation as well as important abilities to move into the new technological fields.If the concepts of broader production are widely implemented in the Swedish FB based CHP sector, this can substantially contribute in the transition towards a bioeconomy.
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| 18. |
- Hallström, Elinor, et al.
(författare)
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How much meat can we eat to sustain a healthy life and planet? The case of Swedish meat consumption
- 2015
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Ingår i: International conference on Life Cycle Assessment as reference methodology for assessing supply chains and supporting global sustainability challenges : LCA FOR “FEEDING THE PLANET AND ENERGY FOR LIFE” - LCA FOR “FEEDING THE PLANET AND ENERGY FOR LIFE”. - 9788882863210 ; , s. 29-35
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Konferensbidrag (refereegranskat)abstract
- Sustainability of Swedish meat consumption is assessed from the perspectives of nutrition, health, climate and land use. Our results suggest that more sustainable food systems can be achieved via changes in Swedish meat consumption and that our multidimensional approach can be useful in identifying such changes.
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| 19. |
- Harvey, Simon, 1965, et al.
(författare)
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Long-term sustainability assessment of fossil-free fuel production concepts
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- The number of possible combinations of feedstock, feedstock pre-treatment, and downstream processes for large-scale production of different types of biofuel is substantial. Different production routes will obviously perform very differently with respect to profitability and carbon footprint. Furthermore, large-scale production of biofuels requires substantial strategic investment decisions, requiring a prospective assessment approach. Evaluation of future biorefinery concepts using today’s conditions can be heavily misleading, and it is therefore essential that possible future conditions and related uncertainties are taken into account. This work explores methodological choices and assumptions of Techno-Economic Assessment (TEA) and Life Cycle Assessment (LCA) methods and tools used in four research groups in Sweden for assessing the long-term economic and carbon footprint performance of large future biorefinery concepts. The report presents an in-depth analysis of the methods and tools used in the participating groups, and clearly establishes the need for increased collaboration and data exchange between biorefinery process developers, value chain modellers, TEA and LCA practitioners and large-scale energy and material system modellers. The work presented constitutes a significant step in this direction by clearly establishing the potential strength of prospective TEA and LCA in combination with scenarios describing possible future developments of the background energy system in which future biofuel production systems will operate. The report presents new results for one of the bio-methane production routes investigated in the “METDRIV - Methane as vehicle fuel – a well-to-wheel analysis” study conducted by Börjesson et al (2016) with respect to energy, greenhouse gas emissions (GHG) and cost performance. The input data used in the original METDRIV study were based on average prices/costs and GHG emission factors valid at the time of the study. In this work, new input data is adopted that reflects possible energy market development pathways generated by the ENPAC energy market scenario tool developed at Chalmers. For the selected production route, the results show that assumptions for costs and greenhouse gas emission factors related to increased use of biomass are of utmost significance, and that there is a clear need for further work in this area. Finally, the report discusses some of the major challenges that remain to be addressed when developing scenarios for the “background” energy system to be used in prospective assessment studies of future biorefinery concepts: Handling the possible consequences of future limited biomass availability on biomass feedstock prices and emission factors. Handling future development of the electric power grid, as well as other large-scale grid energy systems (e.g. district heating) in a carbon-constrained world Integration issues: large-scale biorefinery concepts are likely to be co-located at existing industrial sites, which will also evolve in reaction to policy instruments, thereby affecting opportunities for integration of material and energy flows.
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| 20. |
- Joelsson, Elisabeth, et al.
(författare)
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Integration potential, resource efficiency and cost of forest-fuel-based biorefineries
- 2015
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Ingår i: Computers & Chemical Engineering. - : Elsevier BV. - 1873-4375 .- 0098-1354. ; 82, s. 240-258
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Tidskriftsartikel (refereegranskat)abstract
- A multidisciplinary study of the implementation potential of a biorefinery, using forestry residues as feedstock, is performed by assessing techno-economic factors, system integration and feedstock supply. The process is based on biochemical conversion of logging residues to produce ethanol, biogas, pellets, heat and electricity. Nine models were designed in Aspen Plus based on the available feedstock and the required co-products. Focus was on the product ratio of pellets and heat. The net present value of the plants was calculated and thermal integration with district-heating systems in areas with regional feedstock availability was investigated. Also co-location with pulp and paper mills in Sweden was investigated to replace fossil fuels with pellets. Seven of the nine models showed a positive net present value assuming an 11% discount rate and 30% corporate tax. Five counties in Sweden were identified as potential feedstock suppliers to a biorefinery processing 200 kt dry feedstock/y. (C) 2015 Elsevier Ltd. All rights reserved.
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| 21. |
- Olofsson, Johanna, et al.
(författare)
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Greenhouse gas emissions of methanol from co-gasification of black liquor with by-product biomass
- 2018
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Rapport (övrigt vetenskapligt/konstnärligt)abstract
- En hållbar omställning av transportsystemet kan komma att kräva olika typer av bränslen, tekniker och infrastrukturförändringar, och som ett möjligt alternativ finns biodrivmedel. En potentiell resurs för biodrivmedelsproduktion i Sverige är svartlut, en ligninrik biprodukt från pappers- och massaindustrin, som kan förgasas och omvandlas till metanol. Mängden svartlut som finns tillgänglig begränsas av massaproduktionen men ett sätt att utöka potentialen för biodrivmedelsproduktion kan vara att blanda svartlut med andra typer av biomassabiprodukter i samförgasning, och på så sätt utöka råvarubasen för förgasning samtidigt som en potentiellt effektiv omvandlingsprocess för biprodukter till biodrivmedel görs möjlig. Därmed kan fördelarna med samförgasning vara dubbla.Utav biomassabiprodukter som möjligen skulle kunna användas i samförgasning med svartlut utreds här tre alternativ:i) pyrolysvätska gjord av grot,ii) råglycerol från RME-produktion,iii) fasta fermenteringsrester från cellulosabaserad etanolframställning.Möjligheten att producera hållbart biodrivmedel från dessa resurser och samförgasningssystem kräver dock att ytterligare aspekter, däribland miljömässiga, beaktas. Syftet med denna studie är därför att utvärdera växthusgasutsläppen av bränslen från samförgasning av svartlut med biomassabiprodukter, såväl som mängden bränsle som dessa system kan producera. För att underlätta tolkning av resultaten jämförs dessutom varje samförgasningsscenario med ett referensscenario där alternativ hantering av både svartlut och biomassabiprodukt (i-iii) sker. För varje typ av biomassaprodukt utreds ett låginblandnings- och ett höginblandningsfall, samt produktion av två olika typer av metanolbränsle.Växthusgasutsläppen från samförgasning av svartlut med i) pyrolysvätska, ii) råglycerol och iii) fermenteringsrester utreddes med två livscykelbaserade beräkningssätt, dels utifrån kriterierna i EU:s förnybarhetsdirektiv och dels utifrån ISO-standarderna för livscykelanalys. För referensscenarier antogs den alternativa hanteringen vara förgasning av svartlut, direktförgasning av grot, rötning (anaerobisk nedbrytning) av råglycerol och förbränning med elproduktion för fermenteringsrester.Resultaten skiljer sig mellan de olika samförgasningssystemen både vad gäller växthusgasutsläpp och bränsleproduktion. För grot medför det adderade konverteringssteget i form av pyrolys, som är nödvändigt för samförgasning med svartlut, en förlust som inte kan kompenseras för av förgasningens omvandlingseffektivitet. Således produceras mer metanol i referensscenariot. Vad gäller växthusgasutsläpp ger samförgasnings- och referensscenarierna i liknande resultat, om än något lägre utsläpp för referensscenariot i höginblandningsfallen. För glycerol produceras liknande mängder drivmedel i samförgasnings- och referensscenarierna men med något lägre växthusgasutsläpp i samförgasningsscenarierna på grund av metanläckage från rötningsprocesserna. För fermenteringsrester resulterar den låga omvandlingseffektiviteten i elproduktionen till ett energimässigt lägre utbyte, men också med svårigheten att jämföra metanol och elektricitet. Växthusgasutsläppen är i grova drag jämförbara mellan samförgasnings- och referensscenarierna även om jämförelsen mellan systemen påverkas av valet av beräkningsmetod (RED eller ISO). Generellt ger ISO-metoden högre växthusgasutsläpp vilket förklaras av att fler processer inkluderas i beräkningarna. För samtliga studerade system visar beräkningar av växthusgasutsläpp enligt RED att alla fall och scenarier uppfyller det nuvarande kravet på 60 % utsläppsreduktion jämfört med en referens för fossilbaserat bränsle.Med resultaten följer en rad osäkerhetsaspekter, inte minst vad gäller tillgänglighet till och marknader för biomassabiprodukter, och även vad gäller utvecklingen av det svenska energisystemet i stort. För det första baseras de modellerade systemen på den tekniska möjligheten att blanda biproduktbiomassa med svartlut för samförgasning och metanolproduktion i en framtida, storskalig, integrerad massa- och biodrivmedelsanläggning. Framtida tillgänglighet till råvarorna har därmed inte beaktats explicit i denna rapport. För det andra bidrar elanvändning till en betydande del av växthusgasutsläppen för samtliga studerade samförgasningssystem och utvecklingen av det nordiska elsystemet påverkar på så vis resultaten. Andra viktiga parametrar att nämna i samband med osäkerhet och växthusgasutsläpp är klimatpåverkan från förändringar i skogsmarkens kollager till följd av grotuttag, som illustreras här med ISO-beräkningar, och den antagna alternativa användningen av biomassabiprodukter.Denna studie visar att samförgasning av svartlut med en utökad råvarubas skulle kunna omvandla biomassa till biodrivmedel med en effektivitet och klimatprestanda som är jämförbar med alternativ hantering av biomassaresurserna. Därmed kan de undersökta biomassabiprodukterna utöka råvarubasen för metanolproduktion genom samförgasning med svartlut, men samförgasningen verkar inte ge några fördelar i termer av effektivitet och växthusgasutsläpp jämfört med andra möjliga tekniker som skulle kunna omvandla biprodukterna till biobränsle. På grund av nämnda osäkerhetsaspekter bör resultaten dock tolkas med försiktighet. Ytterligare utförliga studier med specifika data för varje enskilt fall skulle behövas för att adressera några av osäkerheterna och dra vidare slutsatser.
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| 22. |
- Olofsson, Johanna, et al.
(författare)
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Integrating enzyme fermentation in lignocellulosic ethanol production: life-cycle assessment and techno-economic analysis
- 2017
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Ingår i: Biotechnology for Biofuels. - : Springer Science and Business Media LLC. - 1754-6834. ; 10
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Tidskriftsartikel (refereegranskat)abstract
- BackgroundCellulase enzymes have been reported to contribute with a significant share of the total costs and greenhouse gas emissions of lignocellulosic ethanol production today. A potential future alternative to purchasing enzymes from an off-site manufacturer is to integrate enzyme and ethanol production, using microorganisms and part of the lignocellulosic material as feedstock for enzymes. This study modelled two such integrated process designs for ethanol from logging residues from spruce production, and compared it to an off-site case based on existing data regarding purchased enzymes. Greenhouse gas emissions and primary energy balances were studied in a life-cycle assessment, and cost performance in a techno-economic analysis.ResultsThe base case scenario suggests that greenhouse gas emissions per MJ of ethanol could be significantly lower in the integrated cases than in the off-site case. However, the difference between the integrated and off-site cases is reduced with alternative assumptions regarding enzyme dosage and the environmental impact of the purchased enzymes. The comparison of primary energy balances did not show any significant difference between the cases. The minimum ethanol selling price, to reach break-even costs, was from 0.568 to 0.622 EUR L−1 for the integrated cases, as compared to 0.581 EUR L−1 for the off-site case.ConclusionsAn integrated process design could reduce greenhouse gas emissions from lignocellulose-based ethanol production, and the cost of an integrated process could be comparable to purchasing enzymes produced off-site. This study focused on the environmental and economic assessment of an integrated process, and in order to strengthen the comparison to the off-site case, more detailed and updated data regarding industrial off-site enzyme production are especially important.
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| 23. |
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| 24. |
- Olofsson, Johanna, et al.
(författare)
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Residual biomass as resource – Life-cycle environmental impact of wastes in circular resource systems
- 2018
-
Ingår i: Journal of Cleaner Production. - : Elsevier BV. - 0959-6526. ; 196, s. 997-1006
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Tidskriftsartikel (refereegranskat)abstract
- Within an envisioned circular bio-based economy, a key component is the valorization of biomass wastes and residues into valuable products. If the commonly used method of life-cycle assessment (LCA) is applied to such products, an update and adaptation of LCA practice is needed regarding potentially outdated assumptions of residual resources as free from environmental impact. This paper therefore presents and discusses LCA approaches to evaluating residual biomass as resources, and implications of different approaches to LCA results and decision-making. Based on an analysis of 31 LCA studies of bio-based products, and on a model for recycling in LCA, we discuss alternatives to zero-burden assumptions for biomass residues. The studied literature shows a variety of approaches to assessing the impacts of residues, including views of relevant characteristics and causality in primary production systems, and intended use and interpretation of LCA results. In general, acknowledging upstream impacts through a simple model of recycling and allocation entails that the environmental characteristics of primary production systems reflect on by-products and residues. We argue that LCA studies of residue valorization must recognize the potential value of residues by considering upstream impacts, and thereby avoid both misconceptions of residues as per default environmentally preferable resources, and unintentional support for high-impact primary production systems. Residues as resources require this adaptation in LCA practice in order to avoid misguided decisions for a low-impact, bio-based and circular economy.
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| 25. |
- Soam, Shveta, 1987-, et al.
(författare)
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Global warming potential and energy analysis of second generation ethanol production from rice straw in India
- 2016
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Ingår i: Applied Energy. - : Elsevier BV. - 0306-2619 .- 1872-9118. ; 184, s. 353-364
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Tidskriftsartikel (refereegranskat)abstract
- The environmental sustainability of cellulosic ethanol production from rice straw in India is conducted using life cycle assessment (LCA). Greenhouse gas (GHG) emissions, net energy ratio (NER) and net energy balance (NEB) are studied for ethanol production system using two diverse pretreatment technologies, i.e. dilute acid (DA) and steam explosion (SE) followed by separate hydrolysis and fermentation. 1 ton of rice straw is the reference flow of study and 1 MJ transportation fuel is the functional unit while comparing the results with gasoline. The inventory data is collected based on several experiments conducted at our pilot plant and is a novel contribution to country specific LCA. Using DA and SE, the ethanol yields from the processing of 1 ton straw are 239 and 253 L and life cycle GHG emissions are 292 and 288 kg CO2 eq./ton straw respectively. The results indicated that production of enzyme used in hydrolysis is the major contributor to GHG emissions in both DA (54%) and SE (57%) methods of ethanol production. The net energy input during the life cycle of ethanol is 1736 and 1377 MJ/ton straw in DA and SE respectively. The major GHG emissions and energy benefits are obtained using lignin produced in the plant to generate electricity resulting in displacement of the coal based electricity. With a higher xylose recovery in the SE, it gives larger amount of ethanol and also generates more surplus electricity. Enzyme production and its use are identified as GHG emission and energy consumption hotspot in the ethanol production process. While comparing the results with gasoline, DA and SE resulted in a reduction of 77 and 89% GHG emissions and NER of 2.3 and 2.7 respectively. The E5 blending would reduce GHG emissions by 4.3% (DA) and 4.8% (SE) whereas; E20 blend would lead to a reduction of 17.4% (DA) and 18.8% (SE) respectively. Sensitivity analysis indicates that with every 12.5% increase in the price of rice straw from the base case, there is a 2.3% increase in GHG emissions and vice versa. 1 FPU/g WIS increase during hydrolysis gives 2.9% increase in ethanol production, but at the same time there is an increase of 5% emissions from enzyme production. The results of the study conclude that cellulosic ethanol production technology in India is sustainable from GHG reduction and energy efficiency perspective.
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| 26. |
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| 27. |
- Styles, David, et al.
(författare)
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Climate regulation, energy provisioning and water purification : Quantifying ecosystem service delivery of bioenergy willow grown on riparian buffer zones using life cycle assessment
- 2016
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Ingår i: Ambio: a Journal of the Human Environment. - Cham : Springer Science and Business Media LLC. - 0044-7447 .- 1654-7209. ; 45:8, s. 872-884
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Tidskriftsartikel (refereegranskat)abstract
- Whilst life cycle assessment (LCA) boundaries are expanded to account for negative indirect consequences of bioenergy such as indirect land use change (ILUC), ecosystem services such as water purification sometimes delivered by perennial bioenergy crops are typically neglected in LCA studies. Consequential LCA was applied to evaluate the significance of nutrient interception and retention on the environmental balance of unfertilised energy willow planted on 50-m riparian buffer strips and drainage filtration zones in the Skåne region of Sweden. Excluding possible ILUC effects and considering oil heat substitution, strategically planted filter willow can achieve net global warming potential (GWP) and eutrophication potential (EP) savings of up to 11.9 Mg CO2e and 47 kg PO4e ha−1 year−1, respectively, compared with a GWP saving of 14.8 Mg CO2e ha−1 year−1 and an EP increase of 7 kg PO4e ha−1 year−1 for fertilised willow. Planting willow on appropriate buffer and filter zones throughout Skåne could avoid 626 Mg year−1 PO4e nutrient loading to waters.
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