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  • 1.
    Abrahamsson, Louise
    Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Improving methane production using hydrodynamic cavitation as pre-treatment2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    To develop anaerobic digestion (AD), innovative solutions to increase methane yields in existing AD processes are needed. In particular, the adoption of low energy pre-treatments to enhance biomass biodegradability is needed to provide efficient digestion processes increasing profitability. To obtain these features, hydrodynamic cavitation has been evaluated as an innovative solutions for AD of waste activated sludge (WAS), food waste (FW), macro algae and grass, in comparison with steam explosion (high energy pre-treatment). The effect of these two pre-treatments on the substrates, e.g. particle size distribution, soluble chemical oxygen demand (sCOD), biochemical methane potential (BMP) and biodegradability rate, have been evaluated. After two minutes of hydrodynamic cavitation (8 bar), the mean fine particle size decreased from 489- 1344 nm to 277- 381 nm (≤77% reduction) depending of the biomasses. Similar impacts were observed after ten minutes of steam explosion (210 °C, 30 bar) with a reduction in particle size between 40% and 70% for all the substrates treated.  In terms of BMP value, hydrodynamic cavitation caused significant increment only within the A. nodosum showing a post treatment increment of 44% compared to the untreated value, while similar values were obtained before and after treatment within the other tested substrates. In contrast, steam explosion allowed an increment for all treated samples, A. nodosum (+86%), grass (14%) and S. latissima (4%). However, greater impacts where observed with hydrodynamic cavitation than steam explosion when comparing the kinetic constant K. Overall, hydrodynamic cavitation appeared an efficient pre-treatment for AD capable to compete with the traditional steam explosion in terms om kinetics and providing a more efficient energy balance (+14%) as well as methane yield for A. nodosum.

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  • 2.
    Anacleto, Thuane Mendes
    et al.
    Univ Fed Rio de Janeiro, Brazil; Univ Fed Rio de Janeiro, Brazil.
    Kozlowsky-Suzuki, Betina
    Fed Univ State Rio De Janeiro, Brazil; Fed Univ State Rio De Janeiro, Brazil; Fed Univ State Rio De Janeiro, Brazil.
    Björn, Annika
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Solutions Research Center.
    Shakeri Yekta, Sepehr
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Solutions Research Center.
    Masuda, Laura Shizue Moriga
    Ch Mendes Inst Biodivers Conservat ICMBio, Brazil.
    de Oliveira, Vinicius Peruzzi
    Univ Fed Rio de Janeiro, Brazil.
    Enrich Prast, Alex
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Solutions Research Center. Univ Fed Rio de Janeiro, Brazil; Fed Univ Sao Paulo IMar UNIFESP, Brazil.
    Methane yield response to pretreatment is dependent on substrate chemical composition: a meta-analysis on anaerobic digestion systems2024In: Scientific Reports, E-ISSN 2045-2322, Vol. 14, no 1, article id 1240Article in journal (Refereed)
    Abstract [en]

    Proper pretreatment of organic residues prior to anaerobic digestion (AD) can maximize global biogas production from varying sources without increasing the amount of digestate, contributing to global decarbonization goals. However, the efficiency of pretreatments applied on varying organic streams is poorly assessed. Thus, we performed a meta-analysis on AD studies to evaluate the efficiencies of pretreatments with respect to biogas production measured as methane yield. Based on 1374 observations our analysis shows that pretreatment efficiency is dependent on substrate chemical dominance. Grouping substrates by chemical composition e.g., lignocellulosic-, protein- and lipid-rich dominance helps to highlight the appropriate choice of pretreatment that supports maximum substrate degradation and more efficient conversion to biogas. Methane yield can undergo an impactful increase compared to untreated controls if proper pretreatment of substrates of a given chemical dominance is applied. Non-significant or even adverse effects on AD are, however, observed when the substrate chemical dominance is disregarded.

  • 3.
    Andersson, Jim
    et al.
    Luleå University of Technology, Sweden.
    Lundgren, Joakim
    Luleå University of Technology, Sweden.
    Malek, Laura
    Lund University, Sweden.
    Hultegren, Christian
    Lund University, Sweden.
    Pettersson, Karin
    Chalmers University of Technology, Gothenburg, Sweden.
    Wetterlund, Elisabeth
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    System studies on biofuel production via integrated biomass gasification2013Report (Other academic)
    Abstract [en]

    A large number of national and international techno-economic studies on industrially integrated gasifiers for production of biofuels have been published during the recent years. These studies comprise different types of gasifiers (fluidized bed, indirect and entrained flow) integrated in different industries for the production of various types of chemicals and transportation fuels (SNG, FT-products, methanol, DME etc.) The results are often used for techno-economic comparisons between different biorefinery concepts. One relatively common observation is that even if the applied technology and the produced biofuel are the same, the results of the techno-economic studies may differ significantly.

    The main objective of this project has been to perform a comprehensive review of publications regarding industrially integrated biomass gasifiers for motor fuel production. The purposes have been to identify and highlight the main reasons why similar studies differ considerably and to prepare a basis for “fair” techno-economic comparisons. Another objective has been to identify possible lack of industrial integration studies that may be of interest to carry out in a second phase of the project.

    Around 40 national and international reports and articles have been analysed and reviewed. The majority of the studies concern gasifiers installed in chemical pulp and paper mills where black liquor gasification is the dominating technology. District heating systems are also well represented. Only a few studies have been found with mechanical pulp and paper mills, steel industries and the oil refineries as case basis. Other industries have rarely, or not at all, been considered for industrial integration studies. Surprisingly, no studies regarding integration of biomass gasification neither in saw mills nor in wood pellet production industry have been found.

    There are several reasons why the results of the reviewed techno-economic studies vary. Some examples are that different system boundaries have been set and that different technical and economic assumptions have been made, product yields and energy efficiencies may be calculated using different methods etc. For obvious reasons, the studies are not made in the same year, which means that different monetary exchange rates and indices have been applied. It is therefore very difficult, and sometimes even impossible, to compare the technical as well as the economic results from the different studies. When technical evaluations are to be carried out, there is no general method for how to set the system boundaries and no right or wrong way to calculate the system efficiencies as long as the boundaries and methods are transparent and clearly described. This also means that it becomes fruitless to compare efficiencies between different concepts unless the comparison is done on an exactly equal basis.

    However, even on an equal basis, a comparison is not a straight forward process. For example, calculated efficiencies may be based on the marginal supply, which then become very dependent on how the industries exploit their resources before the integration. The resulting efficiencies are therefore very site-dependent. Increasing the system boundaries to include all in- and outgoing energy carriers from the main industry, as well as the integrated gasification plant (i.e. total plant mass and energy balance), would inflict the same site-dependency problem. The resulting system efficiency is therefore a measure of the potential improvement that a specific industry could achieve by integrating a biomass gasification concept.

    When estimating the overall system efficiency of industrial biorefinery concepts that include multiple types of product flows and energy sources, the authors of this report encourage the use of electrical equivalents as a measure of the overall system efficiency. This should be done in order to take the energy quality of different energy carriers into concern.

    In the published economic evaluations, it has been found that there is a large number of studies containing both integration and production cost estimates. However, the number of references for the cost data is rather limited. The majority of these have also been published by the same group of people and use the same or similar background information. The information in these references is based on quotes and estimates, which is good, however none of these are publically available and therefore difficult to value with respect to content and accuracy.

    It has further been found that the variance in the operational costs is quite significant. Something that is particularly true for biomass costs, which have a high variance. This may be explained by natural variations in the quality of biomass used, but also to the different markets studied and the dates when the studies were performed. It may be seen from the specific investment costs that there is a significant spread in the data. It may also be seen that the differences in capital employed and process yields will result in quite large variations in the production cost of the synthetic fuels. On a general note, the studies performed are considering future plants and in some cases assumes technology development. It is therefore relevant to question the use of today’s prices of utilities and feedstock’s. It is believed that it would be more representative to perform some kind of scenario analysis using different parameters resulting in different cost assumptions to better exemplify possible futures.

    Due to the surprising lack of reports and articles regarding integration of biomass gasifiers in sawmills, it would be of great interest to carry out such a study. Also larger scale wood pellet production plants could be of interest as a potential gasification based biorefinery.

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  • 4.
    Björn (Fredriksson), Annika
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Shakeri Yekta, Sepehr
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Ziels, Ryan
    Linköping University, Biogas Research Center. Department of Civil Engineering, University of British Columbia, Columbia, Canada.
    Karl, Gustafsson
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Svensson, Bo H
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Anna, Karlsson
    Linköping University, Biogas Research Center. Scandinavian Biogas Fuels AB, Stockholm, Sweden.
    Feasibility of OFMSW co-digestion with sewage sludge for increasing biogas production at wastewater treatment plants2017In: Euro-Mediterranean Journal for Environmental Integration, ISSN 2365-6433, Vol. 2, no 21Article in journal (Refereed)
    Abstract [en]

    Sweden has the ambition to increase its annual biogas production from the current level of 1.9 to 15 TWh by 2030. The unused capacity of existing anaerobic digesters at wastewater treatment plants is among the options to accomplish this goal. This study investigated the feasibility of utilizing the organic fraction of municipal solid waste (OFMSW) as a co-substrate, with primary and waste-activated sewage sludge (PWASS) for production of biogas, corresponding to 3:1 ratio on volatile solid (VS) basis. The results demonstrated that co-digestion of OFMSW with PWASS at an organic loading rate of 5 gVS l−1 day−1 has the potential to increase the biogas production approximately four times. The daily biogas production increased from 1.0 ± 0.1 to 3.8 ± 0.3 l biogasl−1 day−1, corresponding to a specific methane production of 420 ± 30 Nml methane gVS−1 during the laboratory experiment. Co-digestion of OFMSW with PWASS showed a 50:50 distribution of hydrogenotrophic and aceticlastic methanogens in the digester and enhanced the turnover kinetics of intermediate products (acetate, propionate, and oleate). Practical limitations potentially include the need for sludge dewatering to maintain a sufficient hydraulic retention time (17 days in this study), as well as additional energy consumption for mixing due to an increased sludge apparent viscosity (from 1.8 ± 0.1 to 45 ± 4.8 mPa*s in this study) at elevated OFMSW-loading rates.

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  • 5.
    Carraro, Giacomo
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Tonderski, Karin
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Enrich-Prast, Alex
    Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Solid-liquid separation of digestate from biogas plants: A systematic review of the techniques’ performance2024In: Journal of Environmental Management, ISSN 0301-4797, E-ISSN 1095-8630, Vol. 356, p. 120585-120585, article id 120585Article in journal (Refereed)
    Abstract [en]

    Digestate processing is a strategy to improve the management of digestate from biogas plants. Solid-liquid separation is usually the primary step and can be followed by advanced treatments of the fractions. The knowledge about the performance of the separators and the quality of the fractions is scattered because of many available techniques and large variability in digestate characteristics. We performed a systematic review and found 175 observations of full-scale solid-liquid separation of digestate. We identified 4 separator groups, 4 digestate classes based on substrate, and distinguished whether chemical conditioners were used. We confirmed the hypothesis that the dominant substrate can affect the efficiency of the digestate separation. Furthermore, the results showed that centrifuges separated significantly more dry matter and total P than screw presses. Use of chemical conditioners in combination with a centrifuge lowered the dry matter concentration in the liquid fraction by 30%. Screw presses consumed 4.5 times less energy than centrifuges and delivered 3.3 tonne ammonium N in the liquid fraction and 0.3 tonne total P in the solid fraction using 1 MWh. The results can provide data for systems analyses of biogas solutions and can support practitioners when choosing among full-scale separator techniques depending on the digestate type. In a broader perspective, this work contributes to the continuous improvement of biogas plants operations and to their role as nutrients recovery sites.

  • 6.
    Choong, Ferdinand X.
    et al.
    Karolinska Institute, Sweden.
    Bäck, Marcus
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Steiner, Svava E.
    Karolinska Institute, Sweden.
    Melican, Keira
    Karolinska Institute, Sweden.
    Nilsson, Peter
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Edlund, Ulrica
    KTH Royal Institute Technology, Sweden.
    Richter-Dahlfors, Agneta
    Karolinska Institute, Sweden.
    Nondestructive, real-time determination and visualization of cellulose, hemicellulose and lignin by luminescent oligothiophenes2016In: Scientific Reports, E-ISSN 2045-2322, Vol. 6, article id 35578Article in journal (Refereed)
    Abstract [en]

    Enabling technologies for efficient use of the bio-based feedstock are crucial to the replacement of oil-based products. We investigated the feasibility of luminescent conjugated oligothiophenes (LCOs) for non-destructive, rapid detection and quality assessment of lignocellulosic components in complex biomass matrices. A cationic pentameric oligothiophene denoted p-HTEA (pentamer hydrogen thiophene ethyl amine) showed unique binding affinities to cellulose, lignin, hemicelluloses, and cellulose nanofibrils in crystal, liquid and paper form. We exploited this finding using spectrofluorometric methods and fluorescence confocal laser scanning microscopy, for sensitive, simultaneous determination of the structural and compositional complexities of native lignocellulosic biomass. With exceptional photostability, p-HTEA is also demonstrated as a dynamic sensor for real-time monitoring of enzymatic cellulose degradation in cellulolysis. These results demonstrate the use of p-HTEA as a non-destructive tool for the determination of cellulose, hemicellulose and lignin in complex biomass matrices, thereby aiding in the optimization of biomass-converting technologies.

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  • 7. Order onlineBuy this publication >>
    Dahlgren, Sofia
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Decision-making and decision support connected to biogas use in Sweden2021Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human activities cause many sustainability challenges in the world, which need to be dealt with. One way to decrease the negative impacts related to those challenges is by replacing currently dominating technologies with better, alternative technologies. However, such shifts are not easy to achieve – for example, each new user has to make a decision to start using the technology.The aim of this thesis is to contribute to a greater understanding of what the decisions to use alternative technologies are based on and how the decisions can be supported. In order to achieve this aim, the thesis focuses on the decisions of private companies’ and public organizations in Sweden of whether or not to use biogas in Sweden. The thesis is based upon six appended papers, which are used for addressing three research questions: How do biogas compare to other potential alternatives? Why do decision-makers in Sweden find it interesting to use biogas, and what makes them hesitant? And, how can decision support be used in decision-making to deal with complexities connected to biogas decisions?It is concluded that biogas has environmental and social advantages compared to several other renewable alternatives, but that it can be more expensive. The technical maturity of biogas use depends partly upon the usage area – biomethane buses is a mature area while heavy trucks is less mature. Biogas is perceived by decision-makers as a good environmental option and a better long-term solution than several other renewable alternatives since there are investments done and since the policymakers seem positive towards biogas. Public organizations tend to look at the broader positive aspects of biogas, such as energy security and nutrient recovery, while private companies tend to be more focused on biogas as an environmental action that can benefit the image of the company. However, decision-makers can be hesitant towards biogas due to economic or policy aspects or a lack of technical maturity. The decision-makers can also experience a lack of knowledge that makes them uncertain about biogas. Decision support can help the decision-makers in different ways, with different tools being more suitable for different parts of the complexities connected to biogas decisions. Multi-criteria assessments can help the decision-maker focus on several impacts at once and making the decision process transparent for trade-offs, while socio-technical scenarios can help the decision-maker understand how the wanted changes can be realized.

    List of papers
    1. Biogas-based fuels as renewable energy in the transport sector: an overview of the potential of using CBG, LBG and other vehicle fuels produced from biogas
    Open this publication in new window or tab >>Biogas-based fuels as renewable energy in the transport sector: an overview of the potential of using CBG, LBG and other vehicle fuels produced from biogas
    2022 (English)In: Biofuels, ISSN 1759-7269, E-ISSN 1759-7277, Vol. 13, no 5, p. 587-599Article in journal (Refereed) Published
    Abstract [en]

    The energy supply in the world needs to change from fossil fuels to renewable alternatives. Biogas is such a renewable alternative, and there is potential to increase the biogas production in the world. In recent decades, many countries have increasingly been upgrading biogas to vehicle fuel. In the last few years, the interest has also increased in liquefying biogas for heavier transports. Biogas can also be a raw material for other fuels by gasifying the biogas, for example Fischer-Tropsch fuels, methanol, dimethyl ether and hydrogen. This study provides an overview of vehicle fuels that can be produced from biogas, their technological maturity and their respective potentials as substitutes for fossil fuels in the transport system. A common factor for all of them is that they are most often produced from fossil fuels. Compressed and liquefied methane are the only fuels being commercially produced using biogas. The other fuels all have strengths that both compressed and liquefied methane lack, for example the possibility of emission-free fuel cell vehicles. However, they are all less mature technologies than compressed and liquefied methane. The greatest short-term potential is thus for expanded use of biogas as compressed and liquefied biomethane.

    Place, publisher, year, edition, pages
    TAYLOR & FRANCIS LTD, 2022
    Keywords
    Biogas; transport; biogas-based fuels; compressed biomethane; liquefied biomethane
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-171055 (URN)10.1080/17597269.2020.1821571 (DOI)000574388000001 ()
    Note

    Funding Agencies|Swedish Energy AgencySwedish Energy Agency; Linkoping University; SLU

    Available from: 2020-11-01 Created: 2020-11-01 Last updated: 2022-10-06
    2. Drivers for and barriers to biogas use in manufacturing, road transport and shipping: a demand-side perspective
    Open this publication in new window or tab >>Drivers for and barriers to biogas use in manufacturing, road transport and shipping: a demand-side perspective
    2022 (English)In: Biofuels, ISSN 1759-7269, E-ISSN 1759-7277, Vol. 13, no 2, p. 177-188Article in journal (Refereed) Published
    Abstract [en]

    Contemporary environmental problems require a transition to renewable energy. Biogas is one alternative, which besides being renewable has many other benefits. For further expansion of biogas production, it seems necessary to develop new areas of biogas usage where biogas can replace fossil fuels. This article presents an analysis of the drivers for and barriers to increased biogas usage in three sectors where biogas usage is undeveloped in Sweden: manufacturing, road transport and shipping. Several of the identified drivers and barriers, such as unstable and short-term policies, lack of infrastructure, and contract requirements, have also been found in previous studies even though they may be slightly different depending on the context. A new driver observed in this study is that of intergenerational thinking in family-owned businesses. The study also reiterates the significant influence of policy in the form of subsidies, tax exemptions and regulations on the adoption and use of renewable energy in general and biogas specifically. The results suggest the need for future policymaking to be guided by long-term trajectories, which can be a relevant basis for adopters to make investments into biogas technologies.

    Place, publisher, year, edition, pages
    Taylor & Francis, 2022
    Keywords
    Renewable energy, diffusion, biogas, Sweden
    National Category
    Bioenergy
    Identifiers
    urn:nbn:se:liu:diva-162032 (URN)10.1080/17597269.2019.1657661 (DOI)000492055300001 ()
    Note

    Funding Agencies|Biogas Research Center (BRC); Environmental Bus Project; Swedish Energy AgencySwedish Energy Agency; Linkoping University; VinnovaVinnova; SLU

    Available from: 2019-11-18 Created: 2019-11-18 Last updated: 2022-09-26
    3. Sustainability Assessment of Public Transport, Part I-A Multi-Criteria Assessment Method to Compare Different Bus Technologies
    Open this publication in new window or tab >>Sustainability Assessment of Public Transport, Part I-A Multi-Criteria Assessment Method to Compare Different Bus Technologies
    2021 (English)In: Sustainability, E-ISSN 2071-1050, Vol. 13, no 2, article id 825Article in journal (Refereed) Published
    Abstract [en]

    This article departs from the perspective of Swedish regional transport authorities and focuses on the public procurement of bus transports. Many of these public organizations on the county level have the ambition to contribute to a transition involving the continued marginalization of fossil fuels and improved sustainability performance. However, there are several renewable bus technologies to choose between and it can be difficult to know what alternative (or combination) is preferable. Prior research and the authors experiences indicate a need for improved knowledge and supportive methods on how sustainability assessments can support public procurement processes. The purpose of this article is to develop a multi-criteria assessment (MCA) method to support assessments of public bus technologies sustainability. The method, which was established in an iterative and participatory process, consists of four key areas and 12 indicators. The article introduces the problem context and reviews selected prior research of relevance dealing with green or sustainable public procurement and sustainability assessments. Further on, the process and MCA method are presented and discussed based on advice for effective and efficient sustainability assessments. In the companion article (Part II), the MCA method is applied to assess several bus technologies involving biodiesel, biomethane, diesel, electricity, ethanol and natural gas.

    Place, publisher, year, edition, pages
    MDPI, 2021
    Keywords
    bus technologies; multi-criteria assessment; MCA; MCDA; public transport; sustainability assessment; sustainable or green public procurement
    National Category
    Environmental Management
    Identifiers
    urn:nbn:se:liu:diva-173415 (URN)10.3390/su13020825 (DOI)000611770700001 ()
    Note

    Funding Agencies|Energy Agency of Sweden; Linkoping University; Swedish University of Agriculture

    Available from: 2021-02-20 Created: 2021-02-20 Last updated: 2022-02-10
    4. Sustainability Assessment of Public Transport, Part II - Applying a Multi-Criteria Assessment Method to Compare Different Bus Technologies
    Open this publication in new window or tab >>Sustainability Assessment of Public Transport, Part II - Applying a Multi-Criteria Assessment Method to Compare Different Bus Technologies
    2021 (English)In: Sustainability, E-ISSN 2071-1050, Vol. 13, no 3, article id 1273Article in journal (Refereed) Published
    Abstract [en]

    Many Swedish regional transport authorities want bus fleets driven on renewable fuels. However, it may be difficult to know what technology, or combination of technologies, to choose. There is a need for improved knowledge and supportive methods for sustainability assessments that can support public procurement processes. In the companion article (Part I), a multi-criteria assessment (MCA) method for assessments of public bus technologies sustainability was established, consisting of four key areas and 12 indicators. In this article, the purpose is to apply the method established in part I on different bus technologies by looking at a general Swedish case and assessing buses driven on diesel, Hydrotreated Vegetable Oil (HVO), Fatty Acid Methyl Ester (FAME), ethanol, natural gas, biomethane and electricity. Each technology is assessed on a scale from Very Poor to Very Good according to the indicators: technical maturity, daily operational availability, total cost of ownership, need for investments in infrastructure, cost stability, non-renewable primary energy efficiency, greenhouse gas emission savings, air pollution, noise, local/regional impact on land and aquatic environments, energy security and sociotechnical systems services. The results show the strengths and weaknesses of each technology, which are later discussed. We also critically reflect upon the usefulness and accuracy of the MCA method.

    Place, publisher, year, edition, pages
    MDPI, 2021
    Keywords
    bus technologies; multi-criteria assessment; MCA; MCDA; public transport; sustainability assessment; sustainable or green public procurement
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-174135 (URN)10.3390/su13031273 (DOI)000615680300001 ()
    Note

    Funding Agencies|Energy Agency of Sweden; Swedish University of Agriculture; Linkoping University

    Available from: 2021-03-15 Created: 2021-03-15 Last updated: 2022-02-10
    5. Socio-technical scenarios and local practice: Assessing the future use of fossil-free alternatives in a regional energy and transport system
    Open this publication in new window or tab >>Socio-technical scenarios and local practice: Assessing the future use of fossil-free alternatives in a regional energy and transport system
    2020 (English)In: Transportation Research Interdisciplinary Perspectives, ISSN 2590-1982, Vol. 5Article in journal (Refereed) Published
    Abstract [en]

    This article presents results from a project involving local practitioners in the construction of scenarios for a regional energy and transport system. The purpose is to demonstrate how sustainability transitions research can interact with local practice by means of socio-technical scenarios. Combining quantitative data with qualitative storylines, the article presents four scenarios, which describe different ways of using biogas, biodiesel and electricity in four different applications: city buses, inter-city buses, heavy-duty trucks and industrial processes. The article compares the four scenarios in terms of realization possibilities, energy efficiency and greenhouse gas reduction. Focusing on nearterm realization on a commercial basis, the research findings suggest that collaborative scenario construction can be a useful strategy to manage conflicting agendas and engage key stakeholders in dialogues on transition pathways. The article concludes by presenting policy lessons for practice-oriented transition management. The lessons point to the importance of flexibility in system delineations, the critical timing of near-term scenarios, and the use of scenarios to outline local practitioners' agency.

    Place, publisher, year, edition, pages
    Elsevier, 2020
    Keywords
    Socio-technical scenario Redeployment Biofuels Electric bus Transition management Arena
    National Category
    Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-165756 (URN)10.1016/j.trip.2020.100128 (DOI)2-s2.0-85084598893 (Scopus ID)
    Funder
    Vinnova, 2015-03536Swedish Energy Agency, 2018-010740
    Available from: 2020-05-19 Created: 2020-05-19 Last updated: 2021-09-06Bibliographically approved
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  • 8.
    Dahlgren, Sofia
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Kanda, Wisdom
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Anderberg, Stefan
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Drivers for and barriers to biogas use in manufacturing, road transport and shipping: a demand-side perspective2022In: Biofuels, ISSN 1759-7269, E-ISSN 1759-7277, Vol. 13, no 2, p. 177-188Article in journal (Refereed)
    Abstract [en]

    Contemporary environmental problems require a transition to renewable energy. Biogas is one alternative, which besides being renewable has many other benefits. For further expansion of biogas production, it seems necessary to develop new areas of biogas usage where biogas can replace fossil fuels. This article presents an analysis of the drivers for and barriers to increased biogas usage in three sectors where biogas usage is undeveloped in Sweden: manufacturing, road transport and shipping. Several of the identified drivers and barriers, such as unstable and short-term policies, lack of infrastructure, and contract requirements, have also been found in previous studies even though they may be slightly different depending on the context. A new driver observed in this study is that of intergenerational thinking in family-owned businesses. The study also reiterates the significant influence of policy in the form of subsidies, tax exemptions and regulations on the adoption and use of renewable energy in general and biogas specifically. The results suggest the need for future policymaking to be guided by long-term trajectories, which can be a relevant basis for adopters to make investments into biogas technologies.

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  • 9. Order onlineBuy this publication >>
    Ekstrand, Eva-Maria
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Anaerobic digestion in the kraft pulp and paper industry: Challenges and possibilities for implementation2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The pulp and paper industry is a large producer of wastewater and sludge, putting high pressure on waste treatment. In addition, more rigorous environmental legislation for pollution control and demands to increase the use of renewable energy have put further pressure on the pulp and paper industry’s waste treatment, where anaerobic digestion (AD) and the production of methane could pose a solution. Kraft pulping makes up 80% of the world production of virgin wood pulp, thus, the wastewaters from this sector represent a large unused potential for methane production.

    There are three main types of substrates available for AD at pulp and paper mills, the wastewaters, the primary sludge/fibre sludge, and the waste activated sludge. AD treatment of these streams has been associated with several challenges, such as the presence of inhibiting compounds or low degradability during AD. The aim of this thesis was to experimentally address these challenges and potentials, focusing on wastes from kraft mills.

    Methane potential batch tests showed that many wastewater streams still posed challenges to AD, but the alkaline elemental chlorine-free bleaching stream and the condensate effluents had good methane potentials. Further, the methane potential of kraft mill fibre sludge was high, and co-digestion of kraft mill fibre sludge and waste activated sludge was feasible in stirred tank reactors with sludge recirculation. By increasing the organic loading in a pilot-scale activated sludge facility and thereby lowering the sludge age, the degradability of the waste activated sludge was improved. The higher wastewater treatment capacity achieved by this method provides an opportunity for the mills to increase their pulp and paper production. Further, by dewatering the digestate after AD and returning the liquid to the activated sludge treatment, costs for nutrient supplementation can be reduced.

    In conclusion, the thesis shows that AD of wastes from the kraft pulp and paper industry was feasible and carried many benefits regarding the generation of methane as a renewable energy carrier, improved wastewater treatment and reduced costs. Different strategies on how AD may be implemented in the kraft pulp and paper industry were formulated and discussed.

    List of papers
    1. Methane potentials of the Swedish pulp and paper industry - A screening of wastewater effluents
    Open this publication in new window or tab >>Methane potentials of the Swedish pulp and paper industry - A screening of wastewater effluents
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    2013 (English)In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 507-517Article in journal (Refereed) Published
    Abstract [en]

    With the final aim of reducing the energy consumption and increase the methane production at Swedish pulp and paper mills, the methane potential of 62 wastewater effluents from 10 processes at seven pulp and/or paper mills (A-G) was determined in anaerobic batch digestion assays. This mapping is a first step towards an energy efficient and more sustainable utilization of the effluents by anaerobic digestion, and will be followed up by tests in lab-scale and pilot-scale reactors. Five of the mills produce kraft pulp (KP), one thermo-mechanical pulp (TMP), two chemical thermo-mechanical pulp (CTMP) and two neutral sulfite semi-chemical (NSSC) pulp. Both elementary and total chlorine free (ECF and TCF, respectively) bleaching processes were included. The effluents included material from wood rooms, cooking and oxygen delignification, bleaching (often both acid- and alkali effluents), drying and paper/board machinery as well as total effluents before and after sedimentation. The results from the screening showed a large variation in methane yields (percent of theoretical methane potential assuming 940 NmL CH4 per g TOC) among the effluents. For the KP-mills, methane yields above 50% were obtained for the cooking effluents from mills D and F, paper machine wastewater from mill D, condensate streams from mills B, E and F and the composite pre-sedimentation effluent from mill D. The acidic ECF-effluents were shown to be the most toxic to the AD-flora and also seemed to have a negative effect on the yields of composite effluents downstream while three of the alkaline ECF-bleaching effluents gave positive methane yields. ECF bleaching streams gave higher methane yields when hardwood was processed. All TCF-bleaching effluents at the KP mills gave similar degradation patterns with final yields of 10-15% of the theoretical methane potential for four of the five effluents. The composite effluents from the two NSSC-processes gave methane yields of 60% of the theoretical potential. The TMP mill (A) gave the best average yield with all six effluents ranging 40-65% of the theoretical potential. The three samples from the CTMP process at mill B showed potentials around 40% while three of the six effluents at mill G (CTMP) yielded 45-50%.

    Place, publisher, year, edition, pages
    Elsevier, 2013
    Keywords
    Biogas; Anaerobic digestion; Kraft pulp; Chemical thermo-mechanical pulp; Neutral sulfite semi-chemical pulp; Bleaching
    National Category
    Social Sciences
    Identifiers
    urn:nbn:se:liu:diva-104129 (URN)10.1016/j.apenergy.2012.12.072 (DOI)000329377800053 ()
    Available from: 2014-02-07 Created: 2014-02-07 Last updated: 2021-12-28
    2. High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation
    Open this publication in new window or tab >>High-rate anaerobic co-digestion of kraft mill fibre sludge and activated sludge by CSTRs with sludge recirculation
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    2016 (English)In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, Vol. 56, p. 166-172Article in journal (Refereed) Published
    Abstract [en]

    Kraft fibre sludge from the pulp and paper industry constitutes a new, widely available substrate for thebiogas production industry, with high methane potential. In this study, anaerobic digestion of kraft fibresludge was examined by applying continuously stirred tank reactors (CSTR) with sludge recirculation.Two lab-scale reactors (4L) were run for 800 days, one on fibre sludge (R1), and the other on fibre sludgeand activated sludge (R2). Additions of Mg, K and S stabilized reactor performance. Furthermore, theCa:Mg ratio was important, and a stable process was achieved at a ratio below 16:1. Foaming was abatedby short but frequent mixing. Co-digestion of fibre sludge and activated sludge resulted in more robustconditions, and high-rate operation at stable conditions was achieved at an organic loading rate of 4 gvolatile solids (VS) L1 day1, a hydraulic retention time of 4 days and a methane production of230 ± 10 Nm L per g VS.

    Place, publisher, year, edition, pages
    Elsevier, 2016
    Keywords
    Pulp and paper Anaerobic digestion Sludge recirculation High-rate CSTR Fibre sludge Activated sludge
    National Category
    Renewable Bioenergy Research Production Engineering, Human Work Science and Ergonomics Production Engineering, Human Work Science and Ergonomics Water Engineering
    Identifiers
    urn:nbn:se:liu:diva-131780 (URN)10.1016/j.wasman.2016.06.034 (DOI)000383827700020 ()27453288 (PubMedID)
    Funder
    Swedish Energy Agency
    Note

    Funding agencies: Swedish Energy Agency [32802-1]; Scandinavian Biogas Fuels AB; Poyry AB; BillerudKorsnas AB; SCA; Fiskeby Board AB; Purac AB

    Available from: 2016-10-05 Created: 2016-10-05 Last updated: 2022-10-03Bibliographically approved
    3. Combining high-rate aerobic wastewater treatment with anaerobic digestion of waste activated sludge at a pulp and paper mill
    Open this publication in new window or tab >>Combining high-rate aerobic wastewater treatment with anaerobic digestion of waste activated sludge at a pulp and paper mill
    2018 (English)In: Water Science and Technology, ISSN 0273-1223, E-ISSN 1996-9732, Vol. 77, no 8, p. 2068-2076Article in journal (Refereed) Published
    Abstract [en]

    The activated sludge process within the pulp and paper industry is generally run to minimize the production of waste activated sludge (WAS), leading to high electricity costs from aeration and relatively large basin volumes. In this study, a pilot-scale activated sludge process was run to evaluate the concept of treating the wastewater at high rate with a low sludge age. Two 150 L containers were used, one for aeration and one for sedimentation and sludge return. The hydraulic retention time was decreased from 24 hours to 7 hours, and the sludge age was lowered from 12 days to 2–4 days. The methane potential of the WAS was evaluated using batch tests, as well as continuous anaerobic digestion (AD) in 4 L reactors in mesophilic and thermophilic conditions. Wastewater treatment capacity was increased almost four-fold at maintained degradation efficiency. The lower sludge age greatly improved the methane potential of the WAS in batch tests, reaching 170 NmL CH4/g VS at a sludge age of 2 days. In addition, the continuous AD showed a higher methane production at thermophilic conditions. Thus, the combination of high-rate wastewater treatment and AD of WAS is a promising option for the pulp and paper industry.

    Keywords
    Activated sludge, sludge age, anaerobic digestion, biochemical methane potential, CSTR, pulp and paper
    National Category
    Bioprocess Technology
    Identifiers
    urn:nbn:se:liu:diva-146089 (URN)10.2166/wst.2018.120 (DOI)000435663800011 ()29722692 (PubMedID)
    Note

    Funding agencies: Swedish Energy Agency [32802-2]; Scan-dinavian Biogas Fuels AB; Poyry AB; BillerudKorsnas AB; SCA; Fiskeby Board AB; Purac AB

    Available from: 2018-05-07 Created: 2018-05-07 Last updated: 2022-10-03Bibliographically approved
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    Anaerobic digestion in the kraft pulp and paper industry: Challenges and possibilities for implementation
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  • 10.
    Feizaghaii, Roozbeh
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Carraro, Giacomo
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Brienza, Claudio
    Faculty of Bioscience Engineering, Department of Green Chemistry and Technology, Ghent University, Belgium.
    Meers, Erik
    Faculty of Bioscience Engineering, Department of Green Chemistry and Technology, Ghent University, Belgium.
    Verbeke, Marieke
    Flemish Coordination Centre for Manure Processing, Belgium (currently employed at Trevi Environmental Solutions), Belgium.
    Tonderski, Karin
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Systems analysis of digestate primary processing techniques2022In: Waste Management, ISSN 0956-053X, E-ISSN 1879-2456, ISSN 0956-053X, Vol. 150, p. 352-363Article in journal (Refereed)
    Abstract [en]

    In this paper, we performed technology assessment and systems analysis of primary digestate processing techniques to provide a comprehensive analysis of their environmental and cost performance. We compiled more than 100 observations from large-scale biogas plants and considered digestate based on manure, crops and agro-wastes, and food waste under the geographical contexts of Sweden and Belgium. Centrifuge, screw press, and rotary drum were identified as suitable primary processing techniques. We analyzed the climate impact, energy use, and operational cost of digestate management under these scenarios: no processing, partial processing (solid-liquid separation) and full processing (solid-liquid separation followed by ammonia stripping). As expected, the suitable digestate processing varied with the context, transport was often the most critical cost factor, and emissions from storage reduced the climate savings from the use of biofertilizers. However, treating liquid fraction became a main contributor to cost and climate impact under the Belgian conditions. Consequently, the possibility for local application of liquid fraction as biofertilizer could prevent costs and impacts associated with its further treatment. The main novelty of this work is in its integrative and comprehensive approach toward the choices and impacts of primary processing of digestate. We tried to bridge many individual case studies, drew from experiences of biogas plants in different geographical contexts, assessed suitable processing techniques for different digestate types, and analyzed the environmental impacts and cost of digestate management from a life cycle perspective. We believe that such integrated approaches would help decision-making for increased sustainability of the biogas sector. 

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  • 11.
    Gustafsson, Marcus
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Cordova, Stephanie
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Värdeskapande av koldioxid från biogasproduktion2023Report (Other academic)
    Abstract [en]

    Carbon dioxide (CO₂) has a negative impact on the climate, but it also has several practical areas of use. Many industrial processes emit CO₂ in high concentrations, which could be captured to mitigate emissions while also creating valuable products. One example of such a process is biogas upgrading – a process separating renewable gases, where methane is taken care of for use as vehicle fuel or industrial energy carrier, while CO₂ is released into the atmosphere. The aim of this project has been to chart alternatives and technologies for taking care of green CO₂ from biogas upgrading, so-called carbon capture and utilization (CCU), and to investigate the conditions for applying these in a Swedish context. The work has been guided by the following research questions:

    • How large is the current and future potential for CCU from biogas production?
    • What are the possible areas of use for CO₂ from biogas production?
    • What factors influence the choice of areas of use for CO₂ from biogas production?
    • How large is the environmental benefit of CCU from biogas production?

    To answer these questions, calculations of potentials, a multi-criteria assessment and a life cycle assessment were carried out, based on the Swedish biogas production. A reference group comprising representatives for large Swedish companies within biogas production and biogas upgrading technology was used to enable coproduction and networking between the research group and the business sector.

    The production of CO₂ from biogas was estimated to 160,000 ton/year in 2020, with potential to increase to 540,000 – 840,000 ton/year in a few years and 790,000 – 1,230,000 ton/year in a longer perspective, as a consequence of an expected increase in the Swedish biogas production. A large share of the CO₂ is however produced at relatively small upgrading facilities, which could limit the feasibility for CCU due to high costs for investment and operation. Adding hydrogen to transform all the CO₂ into methane could potentially increase the methane production from biogas from 2 to 3 TWh/year in a short-term perspective and from 11 to 17 TWh/year in a long-term perspective, given sufficient access to hydrogen.

    Other ways of utilizing CO₂ from biogas include production of biomass or chemicals, concrete curing, pH control of process water and use as a refrigerant. The choice of CCU options can be influenced by environmental, technical, economic and policy-related aspects. From the biogas producers’ perspective, methanation is the option that is the most compatible with the existing production system and business model, while other solutions usually involve another actor taking care of the CO₂. Hydrogen is required for methanation as well as for production of chemicals. Another limiting factor are the high purity requirements on all CO₂ that is distributed and sold on the market. The geographical distribution of the production plants can also be a challenge.

    Several CCU options can improve the environmental performance of biogas by replacing fossil-based products. The potential climate impact is the lowest if the CO₂ is methanized with renewable hydrogen or mineralized in concrete, but other forms of environmental impact can also be reduced by applying these or other CCU options. For comparison, permanent storage of CO₂ in geological formations (carbon capture and storage, CCS) only reduces the climate impact, while it increases other forms of environmental impact. Furthermore, permanently storing biogenic CO₂ can make it difficult to reduce the use of fossil CO₂ and transition to a more sustainable society. The need for carbon in many essential processes and products suggests that biogenic CO₂ should be utilized and not stored.

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  • 12.
    Gustafsson, Marcus
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Cordova, Stephanie
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Svensson, Niclas
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Eklund, Mats
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Climate performance of liquefied biomethane with carbon dioxide utilization or storage2024In: Renewable and sustainable energy reviews, Vol. 192, article id 114239Article in journal (Refereed)
    Abstract [en]

    In the process of upgrading biogas to biomethane for gas grid injection or use as a vehicle fuel, biogenic carbon dioxide (CO₂) is separated and normally emitted to the atmosphere. Meanwhile, there are a number of ways of utilizing CO₂ to reduce the dependency on fossil carbon sources. This article assesses the climate performance of liquefied biomethane for road transport with different options for utilization or storage of CO₂. The analysis is done from a life cycle perspective, covering the required and avoided processes from biogas production to the end use of biomethane and CO₂. The results show that all of the studied options for CO₂ utilization can improve the climate performance of biomethane, in some cases contributing to negative CO₂ emissions. One of the best options, from a climate impact perspective, is to use the CO₂ internally to produce more methane, although continuous supply of hydrogen from renewable sources can be a challenge. Another option that stands out is concrete curing, where CO₂ can both replace conventional steam curing and be stored for a long time in mineral form. Storing CO₂ in geological formations can also lead to negative CO₂ emissions. However, with such long-term storage solutions, opportunities to recycle biogenic CO₂ are lost, together with the possibility of de-fossilizing processes that require carbon, such as chemical production and horticulture.

  • 13.
    Gålfalk, Magnus
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Paledal, Soren Nilsson
    Tekniska Verken AB, S-58115 Linkoping, Sweden.
    Yngvesson, Johan
    RISE Res Inst Sweden, Sweden.
    Bastviken, David
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Measurements of Methane Emissions from a Biofertilizer Storage Tank Using Ground-Based Hyperspectral Imaging and Flux Chambers2024In: Environmental Science and Technology, ISSN 0013-936X, E-ISSN 1520-5851Article in journal (Refereed)
    Abstract [en]

    Open storages of organic material represent potentially large sources of the greenhouse gas methane (CH4), an emissions source that will likely become more common as a part of societal efforts toward sustainability. Hence, monitoring and minimizing CH4 emissions from such facilities are key, but effective assessment of emissions without disturbing the flux is challenging. We demonstrate the capacity of using a novel high-resolution hyperspectral camera to perform sensitive CH4 flux assessments at such facilities, using as a test case a biofertilizer storage tank for residual material from a biogas plant. The camera and simultaneous conventional flux chamber measurements showed emissions of 6.0 +/- 1.3 and 13 +/- 5.7 kg of CH4 h-1, respectively. The camera measurements covered the whole tank surface of 1104 m2, and the chamber results were extrapolated from measurements over 5 m2. This corresponds to 0.7-1.4% of the total CH4 production at the biogas plant (1330 N m3 h-1 corresponding to 950 kg h(-1)). The camera could assess the entire tank emission in minutes without disturbing normal operations at the plant and revealed additional unknown emissions from the inlet to the tank (17 g of CH4 h(-1)) and during the loading of the biofertilizer into trucks (3.1 kg of CH4 h(-1) during loading events). This study illustrates the importance of adequate measurement capacity to map methane fluxes and to verify that methane emission mitigation efforts are effective. Given the high methane emissions observed, it is important to reduce methane emissions from open storage of organic material, for example by improved digestion in the biogas reactor, precooling of sludge before storage, or building gastight storage tanks with sealed covers. We conclude that hyperspectral, ground-based remote sensing is a promising approach for greenhouse gas monitoring and mitigation.

  • 14.
    Haglund, Emelie
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Systematisk bedömning av våtmarksväxter som substrat för biogasproduktion2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Two environmental problems today are the increased concentrations of greenhouse gases in the atmosphere and eutrophication.  Therefore, two challenges are reducing greenhouse gas emissions and fluxes of nutrients. Another challenge is to secure the energy supply in a world where energy demand is increasing. New renewable energy sources need to be developed both to secure the energy supply, but also to reduce the use of fossil energy. A renewable energy source is biogas that can be used for electricity, heating and as vehicle fuel. It is predicted that substrate for biogas production will be a limitation in the future, therefore, new substrate need to be evaluated. Wetland plants are an alternative substrate for biogas production and evaluated in this study.  Wetlands and it is plants are interesting to study because they can reduce the concentration of nutrients and therefore help to reduce the problem of eutrophication.  The study was performed within a project at Biogas Research Center and was a literature study with the study of a case. The method used has been developed in the project and is a Multi Criteria Assessment (MCA), which means that there are several different areas being studied. Areas taking into account the biological, economic, chemical, environmental and technological aspects. In order to structure the data, a matrix consisting of the different key areas was used. To clarify the opportunities and obstacles a semi-qualitative assessment was done for each key area. The case studied was a wetland in an agricultural landscape. The wetland is 5 ha and was constructed a few years ago to work as nitrogen and phosphorous trap. There is no vegetation in the wetland because it is relatively new. The plants that were studied during the study was therefore plants that are potential to grow in the wetland in the future. The studied plants were reed, reed canary grass and cattail. In the wetland it is possible to regulate the water and thereby drain the water to facilitate harvesting.   The results showed that the technology available today for the harvesting and chopping needs to be developed because it does not meet the required standards. There are various techniques for digestion, but since the dry matter is high for the plants dry fermentation is preferable, or a two-stage system in which the first step is dry digestion. A wetland provides a relatively small amount of biomass and therefore it is better to co-digest the plants on a farm biogas plant.  Wetland plants are not approved substrates for certification of bio fertilizer, which can be an obstacle. The bio fertilizer also has a low value because the plants contain low levels of nutrients.Wetlands reduce the amount of nutrients and harvest of wetland plants contributes to the retention of phosphorus increases. Wetlands emit methane and nitrous oxide that affect global warming.Today, there is no economic viability of harvesting wetlands. A system in which compensation is obtained for the environmental benefit that harvest provides is an option to increase profitability.

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  • 15.
    Hansson, Anna
    Linköping University, Department of Physics, Chemistry and Biology.
    Mechanism of zeolite activity in biogas co-digestion2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biogas is a source of renewable energy and is produced at anaerobic conditions. The gas consists mainly of methane (55-70 %) and carbon dioxide (30-45 %). Biogas can be used as vehicle fuel after the gas has been upgraded to a methane content of approximately 97 %. There are several companies in Sweden producing biogas. Svensk biogas AB in Linköping is one of the largest. The company has two biogas production plants; one in Linköping and one in Norrköping.

    To meet the surge demand for biogas it is not only important to increase the volumetric capacity of the digesters, but also to optimize the process at the existing production plants in different ways. Zeolites, a clay mineral, have earlier been shown to have a positive effect on anaerobic digestion of certain substrates. The aim of this master’s thesis was to investigate if the organic loading rate could be increased and/or if the hydraulic retention time could be reduced by addition of zeolites to a reactor treating slaughterhouse waste as a substrate. The aim was further to investigate which substance/substances that zeolites possibly could affect.

    Addition of the zeolite clinoptilolite in a continuously stirred lab tank reactor showed a significantly lower accumulation of volatile fatty acids compared to that in a control reactor without zeolites added, when the hydraulic retention time was kept low (30 days) and the organic loading rate was high (4.8 kg VS/ (m3 × day)). The same results were observed upon zeolite addition in a batch experiment, which also showed a decreased lag phase. Neither the specific gas production nor the methane concentration was significantly affected by addition of zeolites. Furthermore, addition of a possible inhibitor, long-chain fatty acids (LCFA), increased the lag phase further when slaughterhouse waste was used as a substrate. The conclusion from the observed results is that a metabolite or metabolites produced during the anaerobic degradation is/are the reason to inhibition and an increased lag phase.

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    Mechanism of zeolite activity in biogas co-digestion
  • 16.
    Harrius, Josefine
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Larsson, Amanda
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Avskiljning, användning och lagring av koldioxid från biogasproduktion: Lämpliga lösningar för Tekniska verkens biogasanläggning2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Carbon dioxide is released by natural and anthropogenic processes, such as the production and combustion of fossil fuels. Production of biogas also generates carbon dioxide, but of biogenic origin. The global, yearly emissions of greenhouse gases are regularly increasing, although agreements such as the Paris Agreement is signed by parties globally. Sweden has the goal to reach net-zero emissions by 2045, and thereafter to only obtain negative emission levels. To reach these goals the biogenic version of Carbon Capture and Storage (CCS) called Bioenergy with Carbon Capture and Storage (BECCS) is considered to be an essential strategy. Using carbon dioxide, through Carbon Capture and Utilization (CCU), in for example products, can complement BECCS since the strategy can increase the value of carbon dioxide. These strategies make it possible to reduce the climate impact of biogas production. 

    This master thesis aimed to chart different techniques in CCS and CCU to examine how they can be used to utilize or store carbon dioxide from biogas plants. What technical demands different solutions create was explored. The different techniques were assessed through a multi criteria analysis by a technological, environmental, marketable and economical standpoint to investigate which ones were the most suitable for a specific, studied case – Tekniska verken’s biogas plant. One suitable technique within CCU was analyzed through a screening of actors in the region. An environmental assessment of one technique in CCS and one in CCU were compared with the reference case Business as usual, to explore how a simulated biogas plant’s climate impact can change through the implementation of CCS and CCU. 

    The charting of literature gave findings of 42 different techniques, which were sifted down to 7; algae farming for wastewater treatment, BECCS in saltwater aquifers, carbon dioxide curing of concrete, bulk solutions, production of methanol, production of methane through Power To Gas and crop yield boosting in greenhouses. The multi criteria analysis pointed out carbon dioxide curing of concrete and BECCS in saltwater aquifers as suitable solutions for the studied case. The implementation of these techniques requires a liquefaction plant, infrastructure for transportation as well as business partners. 

    A life cycle assessment of the studied cases climate impact was given through modelling and simulation of a model plant of the studied case, with the functional unit 1 Nm3 biomethane. The reference case Business as usual had a climate impact of 0,38 kg CO2 eq, which corresponds to approximately one eighth of the climate impact of fossil fuels such as gasoline or diesel. By storing the carbon dioxide through BECCS in saltwater aquifers the climate impact decreased to - 0,42 kg CO2 eq. By utilizing the carbon dioxide through curing of concrete the biomethane’s climate impact decreased to -0,72 kg CO2 eq. The results thereby evince that Swedish biogas producers can improve their climate performance through CCS and CCU. 

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    Avskiljning, användning och lagring av koldioxid från biogasproduktion – Lämpliga lösningar för Tekniska verkens biogasanläggning
  • 17.
    Hellman, Emil
    Linköping University, The Tema Institute, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Lagringstidens påverkan på metanpotentialen i matavfall2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Biogas is a renewable energy source that is produced when organic materials like food waste is degraded by microorganisms under anaerobic (oxygen-free) conditions. The Swedish Government has set goals for a higher sorting of food waste, leading to increased amounts of available substrate for biogas production.

    Collected food waste begin to break down during the time it is transported and stored. The purpose of this study was to investigate the length of the storage, produce a representative recipe for an average food waste in Sweden and evaluate how much methane potential is lost from food waste with respect to the storage time, collection method (paper or plastic bag) and storage temperature (22°C and 6°C) through laboratory tests.

    The average storage time of food waste from houses and apartment buildings in the survey was six days. A recipe for food waste has been developed with the help of literature search and modification of recipes in ‘’Avfall Sverige’’ report U2010:10. Laboratory tests showed that the difference in methane potential between the plastic and paper were clear at 22°C, with decreasing methane potential, but non-existent at 6°C.

    To achieve maximum methane production from food waste during the warmer part of the year, plastic bags are better because they have a preservative effect on the food waste. This can be related to the fact that plastic are denser than paper and therefore holds volatile compounds better.

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  • 18.
    Hjalmarsson, Louise
    Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Hydrolysis of waste activated sludge from pulp and paper mills: effect on dewatering properties and biogas potential by utilizing existing side streams2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A big challenge within pulp and paper mills is the large quantities of waste activated sludge (WAS) that is produced during the wastewater treatment. The WAS is made up of biological cells and extra polymeric substances (EPS) and can bind a large amount of water causing difficulties to dewater the WAS. This study aimed to determine how to improve the dewatering properties of the WAS by using hydrolysis. Hydrolysis will cause the cells to disrupt and the bound water in the cells and the water trapped by the EPS can be released. Specifically, this study investigated what impact hydrolysis with heat, alkalis, and acids had on the WAS dewatering properties. In addition to the impact on the dewatering properties, the release of organic material and nutrients from the cells has also been important for biomethane production. In this study, it was specifically NH4-N, PO43- and COD that have been studied. WAS from paper mills have in general poor methane potential so it was of interest to see how the WAS was affected by hydrolysis and how hydrolysis could improve the methane production.

    To test the hypothesis of whether hydrolysis could affect the WAS and improve the dewatering properties, several experiments were performed. The experiments included thermal hydrolysis at temperatures of 70-90 °C, acidic hydrolysis with acids such as spent acid and acid water, and alkalis such as green liquor sludge and EOP. All acids and alkalis used in the study were chemicals that exist at the paper mills included in this study. To test the dewatering properties, methods such as TS analysis on the accept, CST-analysis, and a belt press were used. Analyses were also performed on the reject to measure the suspended solids and the nutrients NH4 – N, PO43– and COD in the WAS. This study did also determine what effect hydrolysed WAS had on the biomethane potential. In this study were the paper mills BillerudKorsnäs in Skärblacka and SCA in Östrand included. Hence was sludge from the two mills of interest to analyse.

    This study has shown better dewatering properties with an increase in the total solids (in the accept) after the thermal hydrolysis, the acidic hydrolysis with spent acid, and the alkali hydrolysis with green liquor sludge. Specifically did the acidic hydrolysis with spent acid improve the dewatering properties in terms of an increase in TS in %. The biggest increase in TS in % could be seen after using 10% spent acid ratio. The TS for the WAS from SCA Östrand increased in this experiment by 107 %. The thermal hydrolysis also showed promising results both in terms of dewatering properties and in the release of organic material.

    The biochemical methane potential test results showed a better and more rapid stabilized production of biomethane after hydrolysis of WAS compared to untreated WAS. The thermal hydrolysis both increased the rate of production and the total amount of methane produced. The thermally hydrolysed WAS from SCA Östrand improved the methane production from 77 Nml methane/g VS to 95 Nml methane/ g VS. The WAS from BillerudKorsnäs improved the methane production from 40 Nml methane/ g VS to 55 Nml methane/ g VS.

    These results, both from the methane potential tests and the results of the increased dewatering properties, show that the concept with hydrolysing should be evaluated further for improving the dewatering of the WAS.

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    Hydrolysis of waste activated sludge
  • 19.
    Huang, Baitong
    Linköping University, Department of Thematic Studies.
    Comparison of Pre- and Post-treatments of Sugarcane Industry By-products to Increase Biomethane Production2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Even though the Brazilian ethanol and sugar production system (based on sugarcane industry) have been providing large amounts of bioenergy, the extensive amounts of organic wastes generated cannot be ignored when it comes to sustainability. Using these biomasses to produce biomethane through anaerobic digestion has been proven as a promising way to tackle this issue. This study investigated the biomethane potential of the co-digestion of these biomasses: SF (sugarcane straw : filter cake = 8:2), SFV (sugarcane straw : filter cake : vinasse = 1:4:45), and D (digestate separated from AD of SFV). Three treatments autoclaving (AU), alkaline (AL) treatment using 6% (w/w) NaOH and the combination of these two (AUAL) were then conducted on SF and SFV as pre-treatments; on D as post- treatments. In the biomethane potential tests of untreated material, the highest methane yield was achieved by SFV with 275.28 ± 11 N ml CH4/g VS, followed by SF with 223.25 ± 10 N ml CH4 g-1 VS, substrate D also resulted in a methane potential of 144.69 ± 2 N ml CH4 g-1 VS. As pre-treatments, AL and AUAL both showed increase in methane yield (between 36.0% and 49.1%) and methane production rate. As post-treatments, AU, AL and AUAL showed distinctive results in methane production, with 33.8%, 99.8% and 128.8% increase, respectively. In comparison with pre-treatment, post-treatment showed a better performance in increasing methane production. The following feeding experiments performed in continuous stirred-tank reactors showed that AL treatment led to an average of 248% increase in methane yield.

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  • 20.
    JABERIZADEH, HOMA
    Linköping University, Department of Thematic Studies.
    Identifying the Most Optimizing Methods and some Influential Conditions in Methane Yield out of Olive Wastes: A Comprehensive Meta-Analysis On Biochemical Methane Potential Tests2021Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The organic wastes including olive oil mill residues are an inseparable part of food manufacturing processes while implying multi-faceted damages to the environment. A good quantity of research has been conducted to examine the biogas enhancement level in the anaerobic process of olive residues.  Seeking the optimum pretreatment method and the co-digesting substrates, the current study has conducted aggregative research on 155 experiments out of 22 studies. The conducted meta-analysis recognized the chemical type of pretreatments as the most effective treating procedures, according to which, application of the combined alkaline and lime, followed by trace metal cobalt supplementations are recognized as the most effective methods.  Furthermore, the study found intriguing results on the optimum type of olive main substrate, inoculum, digester type and effective volume as well as the superior country and year, in the anaerobic digestion of the olive mill residues.

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  • 21.
    Johansson, Maria
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering. Linköping University, Biogas Research Center.
    Lindkvist, Emma
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, Faculty of Science & Engineering. Linköping University, Biogas Research Center.
    Rosenqvist, Jakob
    Tranås Energi, Sweden.
    Methodology for Analysing Energy Demand in Biogas Production Plants: A Comparative Study of Two Biogas Plants2017In: Energies, E-ISSN 1996-1073, Vol. 10, no 11, article id 1822Article in journal (Refereed)
    Abstract [en]

    Biogas production through anaerobic digestion may play an important role in a circular economy because of the opportunity to produce a renewable fuel from organic waste. However, the production of biogas may require energy in the form of heat and electricity. Therefore, resource-effective biogas production must consider both biological and energy performance. For the individual biogas plant to improve its energy performance, a robust methodology to analyse and evaluate the energy demand on a detailed level is needed. Moreover, to compare the energy performance of different biogas plants, a methodology with a consistent terminology, system boundary and procedure is vital. The aim of this study was to develop a methodology for analysing the energy demand in biogas plants on a detailed level. In the methodology, the energy carriers are allocated to: (1) sub-processes (e.g., pretreatment, anaerobic digestion, gas cleaning), (2) unit processes (e.g., heating, mixing, pumping, lighting) and (3) a combination of these. For a thorough energy analysis, a combination of allocations is recommended. The methodology was validated by applying it to two different biogas plants. The results show that the methodology is applicable to biogas plants with different configurations of their production system.

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  • 22.
    Karlsson, Jonas
    Linköping University, Department of Physics, Chemistry and Biology, Biotechnology.
    Modeling and simulation of existing biogas plants with SIMBA#Biogas2017Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The main purpose of this project was an attempt to modulate and simulate two existing biogas plant, situated in Lidköping and Katrineholm, Sweden and evaluate how the process reacts to certain conditions regarding feeding, layout and substrate mixture. The main goal was to optimize the existing processes to better performance. Both the modeling and simulation were executed in SIMBA#Biogas with accordance to the real conditions at the plant in question. The simulation of each model was validated against data containing measurements of, CH4 yield, CH4 production, TS, VS, NH4-N concentration and N-total concentration. The data was obtained from each plant in accordance with scheduled follow ups. Both models were statistically validated for several predictions. Predictions of N-total and NH4-N concentration failed for some cases. Both plants were tested with new process lay outs, where promising results were obtained. The Lidköping model was provided with a post-hygienization step to handle ABPs. The Katrineholm model was provided with a dewatering unit, where 35% of the centrate was recirculated back to the system. Both setups was configured to yield the highest CH4 production. This study suggests that SIMBA#Biogas can be a tool for predictions and optimizations of the biogas process.

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  • 23.
    Lemetti, Anastasia
    et al.
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Polishchuk, Tatiana
    Linköping University, Department of Science and Technology, Communications and Transport Systems. Linköping University, Faculty of Science & Engineering.
    Saez, Raul
    Tech Univ Catalonia UPC, Spain.
    Prats, Xavier
    Tech Univ Catalonia UPC, Spain.
    Evaluation of Flight Efficiency for Stockholm Arlanda Airport Arrivals2019In: 2019 IEEE/AIAA 38TH DIGITAL AVIONICS SYSTEMS CONFERENCE (DASC), IEEE , 2019Conference paper (Refereed)
    Abstract [en]

    Analysis of punctuality of airport arrivals, as well as identification of causes of the delays within transition airspace, is an important step in evaluating performance of the Terminal Maneuvering Area (TMA) Air Navigation Services: without knowing the current performance levels, it is difficult to identify which areas could be improved. Deviations from the flight plans is one of the major reasons for arrival delays. In this work, we evaluate punctuality of Stockholm Arlanda airport arrivals and quantify the impact of the deviations from the flight plans on the fuel burn. Another reason of fuel waste is non-optimal vertical profiles during the descent phase. We evaluate additional fuel burn due to vertical flight inefficiency within Stockholm TMA.

  • 24.
    Lilja, Dennis
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Konsekvenser av vätgasproduktion för fordonsdrift: klimatpåverkan och energieffektivitet för olika produktionsvägar för vätgas jämfört med fordonsgas och vindkraftsel producerat av energibolag i Östergötland2019Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [sv]

    Sedan 2016 har flera politiska incitament genomförts för att undersöka möjligheten för att få den nordiska vätgasmarknaden att växa. Vätgas är en energibärare med potential att användas som ett miljövänligt drivmedelsalternativ för transportflottan eftersom utsläppen vid användning med bränslecell är rent vatten och bränslecellsbilar har en hög energieffektivitet i jämförelse med bilar med traditionella förbränningsmotorer. De enda utsläppen som förknippas med vätgas är de som sker i samband med produktionen av gasen. Det finns flera olika sätt att producera vätgas ur olika substrat. Idag produceras den mesta vätgasen från naturgas på raffinaderier för användning i bensin- och dieselproduktion. Det planeras en expansion av tankstationer för vätgas i Sverige, men då det finns få producenter så finns det ett intresse för Tekniska verken i Linköping AB att undersöka vad olika produktionsvägar för vätgas har för fördelar och nackdelar i jämförelse med andra biodrivmedel som fordonsgas och elektricitet. Studiens syfte var att undersöka tekniskt lämpliga produktionsvägar för vätgas som är kompatibla med biogasproduktion eller vindkraftsel, och jämföra de olika produktionsvägarna med biogas och vindkraftsel i relation till klimatpåverkan och energieffektivitet då drivmedel för 100 km körsträcka produceras. Efter en teknisk screening av vätgasproduktion, biogasproduktion och elektricitet från vindkraft konstanterades att vätgasproduktion viaångreformering av biogas, tvåstegsrötning av organiskt avfall och PEM-elektrolys är de produktionsvägar som har bäst potential för miljövänlig vätgasproduktion hos Tekniska verken i Linköping AB. Vidare kartlades viktiga parametrar för modellering och simulering av klimatpåverkan i programvaran simaPro. För jämförelse av produktionsvägarna för vätgas från rötning av matavfall användes WTW-metodik. För jämförelsen mellan elektricitet och elektrolys användes modifierad LCA-metodik med klimatpåverkan för hela livscykeln för vindkraftverket men för resterande processteg användes endast klimatpåverkan för driften för produktionen. Resultaten för jämförelsen mellan produktion av biogas, ångreformering och tvåstegsrötning visar ingen tydlig skillnad i varken klimatpåverkan eller energieffektivitet. Studien påvisar däremot att ångreformering av fordonsgas behöver mindre mängd matavfall för produktion av drivmedel för 100 km körsträcka (38 kg/100km) i jämförelse med tvåstegsrötning (44 kg/100km) och biogas (54 kg/100 km). För jämförelsen mellan produktion av vätgas via elektrolys och vindkraftsel visades systemet för vindkraftsel (23,6 kWh/100 km) vara dubbelt så energieffektivt jämfört med systemet för elektrolys (50,9 kWh/100 km), medan systemens klimatpåverkan förhöll sig till en liknande ratio med 0,154 kg CO2-eq utsläpp/100 km i jämförelse med 0,343 kg CO2-eq utsläpp/100 km. Studien visar att vid analys av energieffektivitet och klimatpåverkan för närbesläktade produktionssystem så spelar energieffektiviteten i använd bil stor roll för resultatet. Studiens resultat är framförallt intressant för svenska energibolag som vill veta mer om vätgasproduktion och hur dess klimatnytta och energiproduktion förhåller sig till andra fossilfria drivmedel.

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  • 25.
    Lindfors, Axel
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Eklund, Mats
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Samhällseffekter av alternativa drivmedel2019Report (Other academic)
    Abstract [sv]

    För att uppnå en fossiloberoende fordonsflotta i Östergötlands krävs ökad elektrifiering och mer biodrivmedel, så kallade alternativa drivmedel. För att uppnå detta mål undersöks i rapporten följande: samhällseffekter från produktion och användning av alternativa drivmedel, samhällseffekternas storleksordningar, samhällseffekternas ursprung (produktion eller användning) samt hur olika alternativa drivmedel ger upphov till olika samhällseffekter.

    Rapporten utgår från Sveriges miljömål och BRP+ för att beskriva vilka samhällseffekter produktion och användning av alternativa drivmedel för med sig. 12 huvudområden och 16 indikatorer formulerades, utifrån Sveriges miljömål och BRP+, och dessa används i rapporten för att bedöma samhällseffekterna av fem olika alternativa drivmedel (biogas, etanol, HVO, el och vätgas). Huvudområdena som bedömdes var ökad resursåtervinning, förbättrad luftkvalitet, ökade investeringar i alternativa drivmedel, ökad biodiversitet och minskad ekotoxicitet, ökad tillgänglighet, minskat buller, minskad försurning & övergödning, ökad regional sysselsättning, ökad regional lönesumma, mer förnybar energi och ökad energisäkerhet, minskad klimatpåverkan samt ökad näringsåtervinning.

    För att belysa samhällseffekternas storleksordningar användes även fyra scenarion med olika stor mängd produktion och användning av alternativa drivmedel. Dessa scenarion applicerades på fyra av huvudområdena: ökad regional sysselsättning, ökad regional lönesumma, mer förnybar energi och ökad energisäkerhet samt minskad klimatpåverkan. Resultatet av detta blev exempelvis att produktion av alternativa drivmedel i framtiden utgöra mellan 0,8 och 1,2 % av den regionala lönesumman samt användning av dessa reducera Östergötlands totala klimatgasutsläpp med mellan 17 % och 52 %. Det stora spannet beror på vilka alternativa drivmedel som produceras samt i vilken mängd.

    Illustrationer gjordes för att visa vilka alternativa drivmedel som ger upphov till vilka samhällseffekter. Dessa visar relativ storlek och om effekten är positiv eller negativ för samhället. Dessa illustrationer visar att det är viktigt att utvärdera alternativa drivmedel ur ett multi-dimensionellt perspektiv för att inte missa externa effekter och mervärden.

    Till sist visade samhällseffektsbedömningen att vissa samhällseffekter endast uppkommer i produktionen respektive användningen av alternativa drivmedel. Om målet är att uppnå så många positiva samhällseffekter som möjligt krävs det alltså både produktion och användning. Idag importeras majoriteten av våra alternativa drivmedel, alltså går vi miste om produktionseffekterna. Detta är med hög sannolikhet en konsekvens av det fokus på användningseffekter, främst klimatpåverkan, som länge dominerat samhällsdebatten på detta ämnesområde. Nu behövs policy, strategier och initiativ som både stimulerar produktion och användning av alternativa drivmedel så att alla positiva samhällseffekter uppnås.

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  • 26.
    Lindfors, Axel
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Eklund, Mats
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, Faculty of Science & Engineering.
    Peltonen Ramkvist, Erika
    Region Östergötland.
    Östergötlands potential för biodrivmedelsproduktion och utökad elektrifiering: Delprojektrapport delprojekt 2: Hållbara transporter i Östergötland2018Report (Other academic)
    Abstract [sv]

    För att möta bestämmelser om en fossiloberoende fordonsflotta och uppfylla direktivet om förnybar energi krävs en ökad mängd biodrivmedel- och elanvändning i fordon. Dessa mål införlivas genom lokala och regionala initiativ runt om i Sverige. Inhemsk produktion av biodrivmedel för med sig en mängd positiva effekter så som säkrad bränsletillgång, ökad lokal sysselsättning, mer skatteintäkter och en säker avfallshantering av organiskt avfall. För att ge underlag till hur Östergötland bör agera för att bidra till en fossiloberoende fordonsflotta inventeras i denna rapport Östergötlands biomassa- och biodrivmedelpotential samt länets elnätskapacitet.

    Studien har applicerat en metod där tidigare studier och intervjuer med sakkunniga legat till grund för datainsamlingen. Därefter har en syntes om hur framtiden för Östergötlands biodrivmedelpotential kan se ut arbetats fram av projektgruppen. Under hela projektets arbetsgång har intressenter varit delaktiga, både med information och data men även i att utforma projektets tillvägagångssätt, upplägg och presentation. Denna höga grad av intressentengagemang bidrar till att resultatet blir mer relevant och att intressenter känner sig mer delaktiga i projektets resultat. Dessutom ökar lärandet från projektet då projektgruppen och intressenter delar med sig mer fritt av erfarenheter och kunskap.

    Resultatet visar att Östergötland har goda förutsättningar för ökad biodrivmedelproduktion och ökad elektrifiering av vägtrafiken. Idag kommer större delen av biodrivmedel i Östergötland från primärråvaror eller avfall från hushåll och kommunala aktiviteter. För att realisera en större potential krävs att lantbruks- och skogsbrukssektorerna involveras i högre grad. De mest lovande substraten som inte idag används är flytgödsel, fastgödsel, vall, avloppsvatten från pappers- och massabruk samt skogsrester. Dessa kan tidigt realiseras och tillsammans står de för en betydande del av potentialen. Östergötlands biodrivmedelspotential uppskattas till 3 400 GWh per år. En stor del av denna potential är svårrealiserad och kräver stora insatser om den ska realiseras till 2030.

    Elnätets kapacitet i Östergötland identifieras inte som något kortsiktigt problem av elnätsbolagen i Östergötland. Om elnätet får problem att hantera en ökad elfordonsflotta ger detta först upphov till elkvalitetsproblem och sedan att nätet kan slås ut. Gällande personbilar kan hushållsnära laddning medföra att elserviser och transformatorer måste förstärkas i vissa områden (framförallt i förorter och på landsbygden). På längre sikt kan en kraftig ökning av eldrivna fordon göra att kapacitet i vissa lokala elnät måste byggas ut. I dessa områden kan finansiering bli en kritisk fråga då potentiella elbilsägare kan välja att avstå från att byta bil om det medför att de måste betala en högre nätavgift. Samtidigt blir sannolikt icke-elbilsägare inte glada om de måste betala en högre avgift för att andra skaffar elbil i deras område. För tung- och busstrafik kan vissa punkter bli kritiska och kräva stora förstärkningar. Större vägstråk, bussdepåer och rastplatser kommer behöva klara av att flera fordon kan ladda med iii hög effekt under samma tid på dagen. På dessa platser behövs sannolikt elnätet förstärkas.

    På grund av att elnätsprojekt ofta har lång ledtid visar analysen av resultatet att el bör prioriteras i personbilar och mindre fordon då de påfrestar elnätet mindre. Denna fordonskategori kan även kompletteras med CBG-fordon (komprimerad biogas) och etanolfordon för att uppnå en högre grad av fossilfria fordon. För tyngre transporter pekar analysen på ED95 (etanoldiesel), LBG (förvätskad biogas), HVO och RME. HVO och RME kan redan idag sättas in i tyngre transporter medan ED95 och LBG är några år bort. På detta sätt fås en kontinuerlig ökning av fossilfria fordon fram till 2030 vilket gynnar klimat, miljö och drivmedelsproducenter.

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  • 27. Order onlineBuy this publication >>
    Martin, Michael
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Industrial Symbiosis in the Biofuel Industry: Quantification of the Environmental Performance and Identification of Synergies2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    The production of biofuels has increased in recent years, to reduce the dependence on fossil fuels and mitigate climate change. However, current production practices are heavily criticized on their environmental sustainability. Life cycle assessments have therefore been used in policies and academic studies to assess the systems; with divergent results. In the coming years however, biofuel production practices must improve to meet strict environmental sustainability policies.

    The aims of the research presented in this thesis, are to explore and analyze concepts from industrial symbiosis (IS) to improve the efficiency and environmental performance of biofuel production and identify possible material and energy exchanges between biofuel producers and external industries.

    An exploration of potential material and energy exchanges resulted in a diverse set of possible exchanges. Many exchanges were identified between biofuel producers to make use of each other’s by-products. There is also large potential for exchanges with external industries, e.g. with the food, energy and chemical producing industries. As such, the biofuel industry and external industries have possibilities for potential collaboration and environmental performance improvements, though implementation of the exchanges may be influenced by many conditions.

    In order to analyze if concepts from IS can provide benefits to firms of an IS network, an approach was created which outlines how quantifications of IS networks can be produced using life cycle assessment literature for guidelines and methodological considerations. The approach offers methods for quantifying the environmental performance for firms of the IS network and an approach to distribute impacts and credits for the exchanges between firm, to test the assumed benefits for the firms of the IS network.

    Life cycle assessment, and the approach from this thesis, have been used to quantify the environmental performance of IS networks by building scenarios based on an example from an IS network of biofuel producers in Sweden. From the analyses, it has been found that exchanges of material and energy may offer environmental performance improvements for the IS network and for firms of the network. However, the results are dependent upon the methodological considerations of the assessments, including the reference system, functional unit and allocation methods, in addition to important processes such as the agricultural inputs for the system and energy systems employed.

    By using industrial symbiosis concepts, biofuel producers have possibilities to improve the environmental performance. This is done by making use of by-products and waste and diversifying their products, promoting a transition toward biorefinery systems and a bio-based economy for regional environmental sustainability.

    List of papers
    1. Improving the Environmental Performance of Biofuels with Industrial Symbiosis
    Open this publication in new window or tab >>Improving the Environmental Performance of Biofuels with Industrial Symbiosis
    2011 (English)In: Biomass and Bioenergy, ISSN 0961-9534, Vol. 35, no 5, p. 1747-1755Article in journal (Refereed) Published
    Abstract [en]

    In the production of biofuels for transport many critics have argued about the poor energyefficiency and environmental performance of the production industries. Optimism is thusset on the production of second generation biofuels, while first generation biofuelscontinue to dominate worldwide. Therefore it is interesting to consider how the environmentalperformance of first generation biofuel industries can be improved. The field ofindustrial symbiosis offers many possibilities for potential improvements in the biofuelindustry and theories from this research field are used in this paper to highlight howenvironmental performance improvements can be accomplished. This comes in the formof by-product synergies and utility synergies which can improve material and energyhandling. Furthermore, the processes and products can gain increased environmentalperformance improvements by the adaption of a renewable energy system which will actas a utility provider for many industries in a symbiotic network. By-products may thereafterbe upcycled through biogas production processes to generate both energy and a biofertilizer. A case study of an actual biofuel industrial symbiosis is also reviewed to providesupport for these theories.

    Place, publisher, year, edition, pages
    Elsevier, 2011
    Keywords
    Industrial Symbiosis, Biogas, Biofuel, Synergies, Industrial Symbiosis, Biogas, Biofuel, Synergies, Industrial Symbiosis, Biogas, Biofuel, Synergies, Industrial Symbiosis, Biogas, Biofuel, Synergies, Industrial Symbiosis, Biogas, Biofuel, Synergies, Industrial Symbiosis, Biogas, Biofuel, Synergies, Industrial Symbiosis, Biogas, Biofuel, Synergies, Industrial Symbiosis, Biogas, Biofuel, Synergies
    National Category
    Natural Sciences
    Identifiers
    urn:nbn:se:liu:diva-67189 (URN)10.1016/j.biombioe.2011.01.016 (DOI)000290238200017 ()
    Funder
    Formas
    Available from: 2011-04-04 Created: 2011-04-04 Last updated: 2019-06-13
    2. Production synergies in the current biofuel industry: Opportunities for development
    Open this publication in new window or tab >>Production synergies in the current biofuel industry: Opportunities for development
    2012 (English)In: Biofuels, ISSN 1759-7269, E-ISSN 1759-7277, Vol. 3, no 5, p. 545-554Article in journal (Refereed) Published
    Abstract [en]

    Background: With criticism about the economic viability and environmental performance of biofuels, theuse of byproducts and integration with external industries could be achieved to improve their performanceand provide further use for byproducts and wastes. Methodology: A review of potential byproduct andutility exchanges between biofuel and external industries has been documented in this article through aliterature review and brainstorming workshop, and results have been classified based on their interactions.Results: It has been found that byproduct exchanges, especially those between biofuel industries, andexchanges between the biofuel industries and the food, feed, agriculture and energy industries, offer manypotential exchanges. Conclusion: The identified synergies offer possibilities for potential collaborationpartners in symbiotic exchanges with the biofuel industry.

    Place, publisher, year, edition, pages
    London: Future Science, 2012
    Keywords
    Biofuels, Synergies, By-product, Industrial Symbiosis
    National Category
    Environmental Sciences
    Identifiers
    urn:nbn:se:liu:diva-84548 (URN)10.4155/bfs.12.52 (DOI)
    Funder
    Formas
    Available from: 2012-10-12 Created: 2012-10-12 Last updated: 2017-12-07
    3. Quantifying the environmental performance of integrated bioethanol and biogas production
    Open this publication in new window or tab >>Quantifying the environmental performance of integrated bioethanol and biogas production
    2014 (English)In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 6, p. 109-116Article in journal (Refereed) Published
    Abstract [en]

    As the production of biofuels continues to expand worldwide, criticism about, e.g. the energy output versus input and the competition with food has been questioned. However, biofuels have the possibility to be optimized in order to improve the environmental performance. This could be accomplished through the use of concepts from industrial symbiosis. This paper provides a quantification of the environmental performance of industrial symbiosis in the biofuel industry through integration of biogas and ethanol processes using a life cycle approach. Results show that although increasing integration is assumed to produce environmental benefits, not all impact categories have achieved this and the results depend upon the allocation methods, energy system and assumptions chosen.

    Place, publisher, year, edition, pages
    Elsevier, 2014
    Keywords
    Ethanol, Biogas, Industrial symbiosis, Environmental impacts, Biofuel, Life cycle assessment
    National Category
    Renewable Bioenergy Research Bioenergy Energy Systems
    Identifiers
    urn:nbn:se:liu:diva-86218 (URN)10.1016/j.renene.2012.09.058 (DOI)000326141000018 ()
    Available from: 2012-12-11 Created: 2012-12-11 Last updated: 2019-06-13
    4. Who gets the benefits? An approach for assessing the environmental performance of industrial symbiosis
    Open this publication in new window or tab >>Who gets the benefits? An approach for assessing the environmental performance of industrial symbiosis
    2015 (English)In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 98, p. 263-271Article in journal (Refereed) Published
    Abstract [en]

    Industrial symbiosis networks are generally assumed to provide economic and environmental benefits for all firms involved, though few quantifications have been produced in the literature, and the methods for these quantifications have varied. This paper provides an approach to quantify the environmental performance of industrial symbiosis networks using guidance from the literature of life cycle assessment. Additionally, an approach to distribute credits due to exchanges for firms in the industrial symbiosis network is outlined. From the approach, influential methodological considerations used for the quantifications are discussed, including e.g. the production of reference systems, allocation methods, system boundaries and functional unit. The implications of such an approach may be beneficial for the industrial symbiosis community and provide information crucial for taxes, subsidies, business relations, expansion possibilities for the network, marketing and other issues related to the environmental performance of firms in the industrial symbiosis network.

    Place, publisher, year, edition, pages
    Elsevier, 2015
    Keywords
    Industrial symbiosis, life cycle assessment, by-product, integration, environmental performance
    National Category
    Environmental Sciences Environmental Engineering Bioenergy Renewable Bioenergy Research
    Identifiers
    urn:nbn:se:liu:diva-90232 (URN)10.1016/j.jclepro.2013.06.024 (DOI)000356194300027 ()
    Available from: 2013-03-21 Created: 2013-03-21 Last updated: 2019-06-13Bibliographically approved
    5. Using LCA to quantify the environmental performance of an industrial symbiosis network: Application in the Biofuels Industry
    Open this publication in new window or tab >>Using LCA to quantify the environmental performance of an industrial symbiosis network: Application in the Biofuels Industry
    (English)Manuscript (preprint) (Other academic)
    Abstract [en]

    It is generally assumed that industrial symbiosis creates economic and environmental benefits for all firms involved, though few quantifications have been produced. The environmental performance of an industrial symbiosis network will be quantified using an approach from previous literature. Additionally, the benefits provided by exchanges have partitioned to firms taking part in the industrial symbiosis network, which may have implications for tax incentives, marketing, expansion and environmental awareness. The current industrial symbiosis network has been found to have benefits compared to reference scenarios produced. However, methodological choices, such as the choice of reference scenario and allocation methods may significantly influence the results of the environmental performance.

    Keywords
    Industrial symbiosis, life cycle assessment, by-product, integration, environmental performance
    National Category
    Environmental Sciences Environmental Engineering Renewable Bioenergy Research Bioenergy
    Identifiers
    urn:nbn:se:liu:diva-90229 (URN)
    Available from: 2013-03-21 Created: 2013-03-21 Last updated: 2018-01-11
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    Industrial Symbiosis in the Biofuel Industry: Quantification of the Environmental Performance and Identification of Synergies
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  • 28.
    Martin, Michael
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Using LCA to quantify the environmental performance of an industrial symbiosis network: Application in the Biofuels IndustryManuscript (preprint) (Other academic)
    Abstract [en]

    It is generally assumed that industrial symbiosis creates economic and environmental benefits for all firms involved, though few quantifications have been produced. The environmental performance of an industrial symbiosis network will be quantified using an approach from previous literature. Additionally, the benefits provided by exchanges have partitioned to firms taking part in the industrial symbiosis network, which may have implications for tax incentives, marketing, expansion and environmental awareness. The current industrial symbiosis network has been found to have benefits compared to reference scenarios produced. However, methodological choices, such as the choice of reference scenario and allocation methods may significantly influence the results of the environmental performance.

  • 29.
    Martin, Michael
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Parsapour, Amin
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Upcycling wastes with biogas production:: An exergy and economic analysis2012In: Venice 2012: International Symposium on Energy from Biomass and Waste, Venice, Italy, 2012Conference paper (Other academic)
    Abstract [en]

    The massive consumption of finite resources creates high economical and environmental costs due to material dispersion and waste generation. In order to overcome this, by-products and wastes may be used, to avoid the use of virgin materials and benefit from the useful inherent energy of the material. By adding value to the material, economic and environmental performance can be improve, which is called upcycling. In this paper, an exergy and economic analysis of a biogas process is examined. In order to investigate if biogas production from wastes can upcycle materials, biogas production from a by-product from the brewing process is examined. From the analysis, the process is found to upcycle the by-product with an increase in exergy and economic benefit due to the generation of biomethane and biofertilizer. This analysis thus shows that by using by-products as such, the sustainability of the system may improve.

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    MMVenice2012
  • 30.
    Martin, Michael
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Svensson, Niclas
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Eklund, Mats
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Who gets the benefits? An approach for assessing the environmental performance of industrial symbiosis2015In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 98, p. 263-271Article in journal (Refereed)
    Abstract [en]

    Industrial symbiosis networks are generally assumed to provide economic and environmental benefits for all firms involved, though few quantifications have been produced in the literature, and the methods for these quantifications have varied. This paper provides an approach to quantify the environmental performance of industrial symbiosis networks using guidance from the literature of life cycle assessment. Additionally, an approach to distribute credits due to exchanges for firms in the industrial symbiosis network is outlined. From the approach, influential methodological considerations used for the quantifications are discussed, including e.g. the production of reference systems, allocation methods, system boundaries and functional unit. The implications of such an approach may be beneficial for the industrial symbiosis community and provide information crucial for taxes, subsidies, business relations, expansion possibilities for the network, marketing and other issues related to the environmental performance of firms in the industrial symbiosis network.

    Download full text (pdf)
    fulltext
  • 31.
    Martin, Michael
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Svensson, Niclas
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Fonseca, Jorge
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Eklund, Mats
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Quantifying the environmental performance of integrated bioethanol and biogas production2014In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 6, p. 109-116Article in journal (Refereed)
    Abstract [en]

    As the production of biofuels continues to expand worldwide, criticism about, e.g. the energy output versus input and the competition with food has been questioned. However, biofuels have the possibility to be optimized in order to improve the environmental performance. This could be accomplished through the use of concepts from industrial symbiosis. This paper provides a quantification of the environmental performance of industrial symbiosis in the biofuel industry through integration of biogas and ethanol processes using a life cycle approach. Results show that although increasing integration is assumed to produce environmental benefits, not all impact categories have achieved this and the results depend upon the allocation methods, energy system and assumptions chosen.

  • 32.
    Martin, Michael
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Svensson, Niclas
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Fonseca, Jorge
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Eklund, Mats
    Linköping University, Department of Management and Engineering, Environmental Technology and Management. Linköping University, The Institute of Technology.
    Who gets the benefits?: An approach for assessing the environmentalperformance of industrial symbiosis2012In: Greening of Industry Network: Support your future today! Turning environmental challenges into business opportunities, 2012Conference paper (Other academic)
    Abstract [en]

    It is generally assumed that industrial symbiosis creates economic and environmental benefits for all firmsinvolved, though only a few quantifications have been produced in the literature. An approach to quantifyenvironmental performance of industrial symbiosis using life cycle assessment has been provided,outlining the choice of functional unit, system boundaries, impact assessment and allocation as well as thedistribution of benefits among firms in the symbiotic activity. The implications of such an approach maybe beneficial for the industrial symbiosis and life cycle assessment communities and provide informationcrucial for taxes, subsidies, business relations, marketing and other issues related to the environmentalperformance of firms in the industrial symbiosis network.

  • 33.
    Martinez, Cristina A.
    et al.
    University of Murcia, Spain; IMIB Arrixaca, Spain.
    Nohalez, Alicia
    University of Murcia, Spain; IMIB Arrixaca, Spain.
    Parrilla, Inmaculada
    University of Murcia, Spain; IMIB Arrixaca, Spain.
    Motas, Miguel
    University of Murcia, Spain; IMIB Arrixaca, Spain.
    Roca, Jordi
    University of Murcia, Spain; IMIB Arrixaca, Spain.
    Romero, Inmaculada
    CSIC, Spain.
    Garcia-Gonzalez, Diego L.
    CSIC, Spain.
    Cuello, Cristina
    University of Murcia, Spain; IMIB Arrixaca, Spain.
    Rodriguez-Martinez, Heriberto
    Linköping University, Department of Clinical and Experimental Medicine, Division of Children's and Women's health. Linköping University, Faculty of Medicine and Health Sciences.
    Martinez, Emilio A.
    University of Murcia, Spain; IMIB Arrixaca, Spain.
    Gil, Maria A.
    University of Murcia, Spain; IMIB Arrixaca, Spain.
    The overlaying oil type influences in vitro embryo production: differences in composition and compound transfer into incubation medium between oils2017In: Scientific Reports, E-ISSN 2045-2322, Vol. 7, article id 10505Article in journal (Refereed)
    Abstract [en]

    The oil overlay micro-drop system is widely used for cultures of mammalian gametes and embryos. We evaluated hereby the effects of two unaltered commercial oils-Sigma mineral oil (S-MO) and Nidoil paraffin oil (N-PO)-on in vitro embryo production (IVP) outcomes using a pig model. The results showed that while either oil apparently did not affect oocyte maturation and fertilization rates, S-MO negatively affected embryo cleavage rates, blastocyst formation rates, and, consequently, total blastocyst efficiency of the system. No differences in the oxidation state were found between the oils or culture media incubated under S-MO or N-PO. Although both oils slightly differed in elemental composition, there were no differences in the concentrations of elements between fresh media and media incubated under oils. By contrast, we demonstrated clear oil-type differences in both the composition of volatile organic compounds (VOC) and the transfer of some of these VOCs (straight-chain alkanes and pentanal and 1,3-diethyl benzene) to the culture medium, which could have influenced embryonic development.

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  • 34.
    Niklasson, Johanna
    et al.
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Bergquist Skogfors, Linnea
    Linköping University, Department of Management and Engineering, Environmental Technology and Management.
    Can organic waste fuel the buses in Johannesburg?: A study of potential, feasibility, costs and environmental performance of a biomethane solution for public transport2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Like many large cities, Johannesburg faces several sustainability challenges such as unsustainable use of natural resources, emissions contributing to environmental- and waste related problems. The city is a provincial transport centre, and the transport sector is responsible for a large share of the city’s energy demand and emissions. To approach several of these challenges simultaneously the City of Johannesburg considers the possibilities to use renewable, waste-based, fuel for public transport and has shown a great interest in how Sweden produce and use biogas. 

    In this study an early assessment of the potential, feasibility, economic costs and environmental performance of a waste-based biomethane solution in Johannesburg is performed, with the purpose to fuel a public transport bus fleet. This has been done by developing and using a multi-criteria analysis (MCA). The MCA consists of four categories: potential, feasibility, economic costs and environmental performance. These categories consist of 17 key areas with corresponding key questions and indicators with relating scales used for scoring the indicators. The indicators and scales help identify what information is necessary to collect for the assessment. Furthermore, an Excel tool and a questionnaire are provided to serve as a help when performing the assessment. The feasibility assessment is conducted both for the city as a whole as well as for individual feedstocks. Information for the studied case was gathered from a literature study and interviews in Johannesburg with local experts and potential stakeholders. 

    The identified feedstocks in Johannesburg are landfill gas, waste from a fruit and vegetable market, organic household waste, abattoir waste, waste from the food industry, waste management companies and sewage sludge from the wastewater treatment plants (WWTP). The identified biomass potential is 230,000 tonnes of dry matter/year, generating a total biomethane potential of 91,600,000 Nm3/year, which is enough to fuel almost 2700 buses. In the process of producing biogas, digestate is created. The digestate can be used as biofertilizer and recycle nutrients when used in agriculture. The complete biomass potential in Johannesburg was not identified meaning there is additional potential, from e.g. other food industries, than examined in this study. 

    Assuming that all feedstocks except for landfill gas and WWTP sludge are processed in one biogas plant, the investment cost for this biogas plant is 28 million USD and the total operation and maintenance cost is 1.4 million USD per year. The investment cost and yearly operating cost for the upgrading plant is 43 million USD and 2.4 million USD respectively. Finally, the distribution costs were calculated, including compression and investment in vessels. The investment and operational costs for compression is 7.4 million USD and 220,000 USD/year respectively. The investment cost for the vessels was calculated to 15 million USD and the operational costs of the distribution 16 million USD/year. Consideration should be given to the fact that the numbers used when calculating these costs comes with uncertainties.

    Most indicators in the feasibility assessment of the city as a whole were given the score Poor, but some indicators were scored Satisfactory or Good. The assessment of the individual feedstocks led to a ranking of the most to the least feasible feedstocks where the waste from the fruit and vegetable market and the municipal household waste are considered being in the top. This assessment also shows the feedstocks are in general quite suitable for biomethane production. The issue is the lack of economic and legislative support and strategies not working in favour of biomethane. These are areas that can be improved by the local or national government to give better conditions for production of biomethane in the future. Some examples of this are a proposed landfill tax or landfill ban as well as a closing of the landfills due to the lack of new land. This could all contribute to better conditions for biomethane solutions in the future. Main identified hinders are electricity generation from biogas as a competitor with biomethane, and a general lack of knowledge about biogas and biomethane, from the high-level decision makers to a workforce lacking skills about construction and operation of biogas plants. 

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  • 35.
    Reuterswärd, Caspar
    Linköping University, Department of Science and Technology.
    Exploring the repurposing of cross laminated timber spillage2019Independent thesis Advanced level (degree of Master (Two Years)), 80 credits / 120 HE creditsStudent thesis
    Abstract [en]

    Forestry is one of Sweden’s largest natural resources and a largeand important foundation for the country’s economic stability.There is a significant opportunity to evaluate material efficiencyand values in the supply chain of industrialised wood-basedproducts. This thesis comprises on handling a spill-product of amodern wood-based building material: cross-laminated timber(CLT). With the aim to increase value of this spill product throughpractical design iteration, material exploration and theoreticalanalysis. The material exploration leads to a collection of furnitureand interior products which are evaluated based on commercialinterest and production feasibility.

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    Exploring the repurposing of cross laminated timber spillage
  • 36.
    Safaric, Luka
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Shakeri Yekta, Sepehr
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Ejlertsson, Jörgen
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center. Scandinavian Biogas Fuels AB.
    Safari, Mohammad
    Linköping University, Department of Management and Engineering. Linköping University, Faculty of Science & Engineering.
    Nadali Najafabadi, Hossein
    Linköping University, Department of Management and Engineering, Applied Thermodynamics and Fluid Mechanics. Linköping University, Faculty of Science & Engineering.
    Karlsson, Anna
    Linköping University, Biogas Research Center. Scandinavian Biogas Fuels AB.
    Ometto, Francesco
    Linköping University, Biogas Research Center. Scandinavian Biogas Fuels AB.
    Svensson, Bo H
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences.
    Björn, Annika
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    A Comparative Study of Biogas Reactor Fluid Rheology: Implications for Mixing Profile and Power Demand2019In: Processes, ISSN 2227-9717, Processes, ISSN 2227-9717, Vol. 7, no 10Article in journal (Refereed)
    Abstract [en]

    Anaerobic digestion (AD) is an established process for integrating waste management with renewable energy and nutrient recovery. Much of the research in this field focuses on the utilisation of new substrates, yet their effects on operational aspects such as fluid behaviour and power requirement for mixing are commonly overlooked, despite their importance for process optimisation. This study analysed rheological characteristics of samples from 21 laboratory-scale continuous stirred-tank biogas reactors (CSTBRs) digesting a range of substrates, in order to evaluate substrate effect on mixing efficiency and power demand through computational fluid dynamics (CFD). The results show that substrate and process parameters, such as solids content and organic loading, all have a significant effect on CSTBR fluid rheology. The correlation levels between rheological and process parameters were different across substrates, while no specific fluid behaviour patterns could be associated with substrate choice. Substrate should thus be considered an equally important rheology effector as process parameters. Additional substrate-related parameters should be identified to explain the differences in correlations between rheological and process parameters across substrate groups. The CFD modelling revealed that the rheology differences among the AD processes have significant implications for mixing efficiency and power demand of the CSTBRs, highlighting the importance of considering the substrate-induced effects on CSTBR rheology before including a new substrate.

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  • 37.
    Shakeri Yekta, Sepehr
    et al.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Liu, Tong
    Linköping University, Biogas Research Center. Swedish Univ Agr Sci, Sweden.
    Mendes Anacleto, Thuane
    Univ Fed Rio de Janeiro, Brazil.
    Axelsson Bjerg, Mette
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Safaric, Luka
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Goux, Xavier
    Luxembourg Inst Sci & Technol, Luxembourg.
    Karlsson, Anna
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center. Scandinavian Biogas Fuels AB, Sweden.
    Björn, Annika
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center.
    Schnurer, Anna
    Linköping University, Biogas Research Center. Swedish Univ Agr Sci, Sweden.
    Effluent solids recirculation to municipal sludge digesters enhances long-chain fatty acids degradation capacity2021In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 14, no 1, article id 56Article in journal (Refereed)
    Abstract [en]

    Background Slow degradation kinetics of long-chain fatty acids (LCFA) and their accumulation in anaerobic digesters disrupt methanogenic activity and biogas production at high loads of waste lipids. In this study, we evaluated the effect of effluent solids recirculation on microbial LCFA (oleate) degradation capacity in continuous stirred-tank sludge digesters, with the overall aim of providing operating conditions for efficient co-digestion of waste lipids. Furthermore, the impacts of LCFA feeding frequency and sulfide on process performance and microbial community dynamics were investigated, as parameters that were previously shown to be influential on LCFA conversion to biogas. Results Effluent solids recirculation to municipal sludge digesters enabled biogas production of up to 78% of the theoretical potential from 1.0 g oleate l(-1) day(-1). In digesters without effluent recirculation, comparable conversion efficiency could only be reached at oleate loading rates up to 0.5 g l(-1) day(-1). Pulse feeding of oleate (supplementation of 2.0 g oleate l(-1) every second day instead of 1.0 g oleate l(-1) every day) did not have a substantial impact on the degree of oleate conversion to biogas in the digesters that operated with effluent recirculation, while it marginally enhanced oleate conversion to biogas in the digesters without effluent recirculation. Next-generation sequencing of 16S rRNA gene amplicons of bacteria and archaea revealed that pulse feeding resulted in prevalence of fatty acid-degrading Smithella when effluent recirculation was applied, whereas Candidatus Cloacimonas prevailed after pulse feeding of oleate in the digesters without effluent recirculation. Combined oleate pulse feeding and elevated sulfide level contributed to increased relative abundance of LCFA-degrading Syntrophomonas and enhanced conversion efficiency of oleate, but only in the digesters without effluent recirculation. Conclusions Effluent solids recirculation improves microbial LCFA degradation capacity, providing possibilities for co-digestion of larger amounts of waste lipids with municipal sludge.

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  • 38.
    Speda, Jutta
    et al.
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Johansson, Mikaela
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering.
    Odnell, Anna
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering. Karshult Municipal Waste Water Treatment Plant, Sweden.
    Karlsson, Martin
    Linköping University, Department of Physics, Chemistry and Biology, Chemistry. Linköping University, Faculty of Science & Engineering. InZymes Biotech AB, Gjuterigatan 1B, S-58273 Linkoping, Sweden.
    Enhanced biomethane production rate and yield from lignocellulosic ensiled forage ley by in situ anaerobic digestion treatment with endogenous cellulolytic enzymes2017In: Biotechnology for Biofuels, ISSN 1754-6834, E-ISSN 1754-6834, Vol. 10, article id 129Article in journal (Refereed)
    Abstract [en]

    Background: Enzymatic treatment of lignocellulosic material for increased biogas production has so far focused on pretreatment methods. However, often combinations of enzymes and different physicochemical treatments are necessary to achieve a desired effect. This need for additional energy and chemicals compromises the rationale of using enzymes for low energy treatment to promote biogas production. Therefore, simpler and less energy intensive in situ anaerobic digester treatment with enzymes is desirable. However, investigations in which exogenous enzymes are added to treat the material in situ have shown mixed success, possibly because the enzymes used originated from organisms not evolutionarily adapted to the environment of anaerobic digesters. In this study, to examine the effect of enzymes endogenous to methanogenic microbial communities, cellulolytic enzymes were instead overproduced and collected from a dedicated methanogenic microbial community. By this approach, a solution with very high endogenous microbial cellulolytic activity was produced and tested for the effect on biogas production from lignocellulose by in situ anaerobic digester treatment. Results: Addition of enzymes, endogenous to the environment of a mixed methanogenic microbial community, to the anaerobic digestion of ensiled forage ley resulted in significantly increased rate and yield of biomethane production. The enzyme solution had an instant effect on more readily available cellulosic material. More importantly, the induced enzyme solution also affected the biogas production rate from less accessible cellulosic material in a second slower phase of lignocellulose digestion. Notably, this effect was maintained throughout the experiment to completely digested lignocellulosic substrate. Conclusions: The induced enzyme solution collected from a microbial methanogenic community contained enzymes that were apparently active and stable in the environment of anaerobic digestion. The enzymatic activity had a profound effect on the biogas production rate and yield, comparable with the results of many pretreatment methods. Thus, application of such enzymes could enable efficient low energy in situ anaerobic digester treatment for increased biomethane production from lignocellulosic material.

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  • 39.
    Tran, David
    Linköping University, The Tema Institute, Tema Environmental Change.
    Hydrodynamic cavitation applied to food waste anaerobic digestion2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Innovative pre-treatment methods applied to anaerobic digestion (AD) have developed to enhance the methane yields of food waste. This study investigates hydrodynamic cavitation, which induce disintegration of biomass through microbubble formations, impact on food waste solubilisation and methane production during following AD. Two different sub-streams of food waste (before and after the digestion) pre-treated by hydrodynamic cavitation were evaluated in lab scale for its potential for implementation in a full scale practise. First, the optimum condition for the hydrodynamic cavitation device was determined based on the solids and chemical changes in the food waste. The exposure time was referred to as the number of cycles that the sample was recirculated through the cavitation inducer’s region. The optimal cycles were later tested as a pre-treatment step in a BMP test and semi-CSTR lab scale operation. The tests showed that sufficient impact from the hydrodynamic cavitation was achieved by 20 cavitation cycles. Due to the pre-treatment, food waste solubilisation increased, up to 400% and 48% in terms of turbidity and sCOD measurements, respectively. In the BMP test, the treated samples improved the methane yield by 9-13%, where the digested food waste increased its kinetic constant by 60%. Fresh food waste was then processed in the semi-CSTR operation and the methane yield was increased by up to 17% with hydrodynamic cavitation for two reference periods. These promising results suggest that the hydrodynamic cavitation can be implemented for full scale production with food waste.

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  • 40.
    Westerholm, M.
    et al.
    Linköping University, Biogas Research Center. Linköping University, Faculty of Arts and Sciences. Swedish Univ Agr Sci, Sweden.
    Liu, T.
    Swedish Univ Agr Sci, Sweden.
    Schnurer, A.
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Faculty of Arts and Sciences. Linköping University, Biogas Research Center. Swedish University of Agricultural Sciences, Uppsala.
    Comparative study of industrial-scale high-solid biogas production from food waste: Process operation and microbiology2020In: Bioresource Technology, ISSN 0960-8524, E-ISSN 1873-2976, Vol. 304, article id 122981Article in journal (Refereed)
    Abstract [en]

    Anaerobic high-solid treatment (HST) for processing food waste and biogas production is a viable technology with considerable commercial potential. In this study, we examined and compared mesophilic and thermophilic industrial-scale plug-flow digesters. The HSTs demonstrated reasonable biogas yields from food waste (0.4-0.6 Nm(3)CH(4)/kg volatile solids). However, during operation at thermophilic conditions ammonia inhibition (similar to 2 g NH3-N/L) and acid accumulation (6-14 g/L) caused severe process disturbance. Microbial community structures diverged between the processes, with temperature appearing to be a strong driver. A unique feature of the thermophilic HSTs was high abundance of the uncultivated Clostridia group MBA03 and temperature fluctuations in one mesophilic HST were linked to drastically decreased abundance of methanogens and relative abundance of Cloacimonetes. The process data obtained in this study clearly demonstrate both potential and challenges in HST of food waste but also possibilities for management approaches to tackle process imbalance and restore process function.

  • 41.
    Wetterlund, Elisabeth
    et al.
    Linköping University, Department of Management and Engineering, Energy Systems. Linköping University, The Institute of Technology.
    Pettersson, Karin
    Chalmers University of Technology.
    Mossberg, Johanna
    SP Technical Research Institute of Sweden .
    Torén, Johan
    SP Technical Research Institute of Sweden .
    Hoffstedt, Christian
    Innventia, Stockholm.
    von Schenck, Anna
    Innventia, Stockholm.
    Berglin, Niklas
    Innventia, Stockholm.
    Lundmark, Robert
    Luleå University of Technology.
    Lundgren, Joakim
    Luleå University of Technology.
    Leduc, Sylvain
    International Institute of Applied Systems Analysis (IIASA).
    Kindermann, Georg
    International Institute of Applied Systems Analysis (IIASA).
    Optimal localisation of next generation biofuel production in Sweden2013Report (Other academic)
    Abstract [en]

    With a high availability of lignocellulosic biomass and various types of cellulosic by-products, as well as a large number of industries, Sweden is a country of great interest for future large scale production of sustainable, next generation biofuels. This is most likely also a necessity as Sweden has the ambition to be independent of fossil fuels in the transport sector by the year 2030 and completely fossil free by 2050. In order to reach competitive biofuel production costs, plants with large production capacities are likely to be required. Feedstock intake capacities in the range of about 1-2 million tonnes per year, corresponding to a biomass feed of 300-600 MW, can be expected, which may lead to major logistical challenges. To enable expansion of biofuel production in such large plants, as well as provide for associated distribution requirements, it is clear that substantial infrastructure planning will be needed. The geographical location of the production plant facilities is therefore of crucial importance and must be strategic to minimise the transports of raw material as well as of final product. Competition for the available feedstock, from for example forest industries and CHP plants (combined heat and power) further complicates the localisation problem. Since the potential for an increased biomass utilisation is limited, high overall resource efficiency is of great importance. Integration of biofuel production processes in existing industries or in district heating systems may be beneficial from several aspects, such as opportunities for efficient heat integration, feedstock and equipment integration, as well as access to existing experience and know-how.

    This report describes the development of BeWhere Sweden, a geographically explicit optimisation model for localisation of next generation biofuel production plants in Sweden. The main objective of developing such a model is to be able to assess production plant locations that are robust to varying boundary conditions, in particular regarding energy market prices, policy instruments, investment costs, feedstock competition and integration possibilities with existing energy systems. This report also presents current and future Swedish biomass resources as well as a compilation of three consistent future energy scenarios.

    BeWhere is based on Mixed Integer Linear Programming (MILP) and is written in the commercial software GAMS, using CPLEX as a solver. The model minimises the cost of the entire studied system, including costs and revenues for biomass harvest and transportation, production plants, transportation and delivery of biofuels, sales of co-products, and economic policy instruments. The system cost is minimised subject to constraints regarding, for example, biomass supply, biomass demand, import/export of biomass, production plant operation and biofuel demand. The model will thus choose the least costly pathways from one set of feedstock supply points to a specific biofuel production plant and further to a set of biofuel demand points, while meeting the demand for biomass in other sectors.

    BeWhere has previously been developed by the International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria and Luleå University of Technology and has been used in several studies on regional and national levels, as well as on the European level. However, none of the previous model versions has included site-specific conditions in existing industries as potential locations for industrially integrated next generation biofuel production. Furthermore, they also usually only consider relatively few different production routes. In this project, bottom-up studies of integrated biofuel production have been introduced into a top-down model and taken to a higher system level, and detailed, site-specific input data of potential locations for integrated biofuel production has been included in the model.

    This report covers the first stages of model development of BeWhere Sweden. The integration possibilities have been limited to the forest industry and a few district heating networks, and the feedstocks to biomass originating from the forest. The number of biofuel production technologies has also been limited to three gasification-based concepts producing DME, and two hydrolysis- and fermentation-based concepts producing ethanol. None of the concepts considered is yet commercial on the scale envisioned here.

    Preliminary model runs have been performed, with the main purpose to identify factors with large influence on the results, and to detect areas in need of further development and refinement. Those runs have been made using a future technology perspective but with current energy market conditions and biomass supply and demand. In the next stage of model development different roadmap scenarios will be modelled and analysed. Three different roadmap scenarios that describe consistent assessments of the future development concerning population, transport and motor fuel demands, biomass resources, biomass demand in other industry sectors, energy and biomass market prices etc. have been constructed within this project and are presented in this report. As basis for the scenarios the report “Roadmap 2050” by the Swedish Environmental Protection Agency (EPA) has been used, using 2030 as a target year for the scenarios. Roadmap scenario 1 is composed to resemble “Roadmap 2050” Scenario 1. Roadmap scenario 2 represents an alternative development with more protected forest and less available biomass resources, but a larger amount of biofuels in the transport system, partly due to a higher transport demand compared to Roadmap scenario 1. Finally Roadmap scenario 3 represents a more “business as usual” scenario with more restrictive assumptions compared to the other two scenarios.

    In total 55 potential biofuel plant sites have been included at this stage of model development. Of this 32 sites are pulp/paper mills, of which 24 have chemical pulp production (kraft process) while eight produce only mechanical pulp and/or paper. Seven of the pulp mills are integrated with a sawmill, and 18 additional stand-alone sawmills are also included, as are five district heating systems. The pulp and paper mills and sawmills are included both as potential biofuel plant sites, as biomass demand sites regarding wood and bioenergy, and as biomass supply sites regarding surplus by-products. District heating systems are considered both regarding bioenergy demand and as potential plant sites.

    In the preliminary model runs, biofuel production integrated in chemical pulp mills via black liquor gasification (BLG) was heavily favoured. The resulting total number of required production plants and the total biomass feedstock volumes to reach a certain biofuel share target are considerably lower when BLG is considered. District heating systems did not constitute optimal plant locations with the plant positions and heat revenue levels assumed in this study. With higher heat revenues, solid biomass gasification (BMG) with DME production was shown to be potentially interesting. With BLG considered as a production alternative, however, extremely high heat revenues would be needed to make BMG in district heating systems competitive.

    The model allows for definition of biofuel share targets for Sweden overall, or to be fulfilled in each county. With targets set for Sweden overall, plant locations in the northern parts of Sweden were typically favoured, which resulted in saturation of local biofuel markets and no biofuel use in the southern parts. When biofuels needed to be distributed to all parts of Sweden, the model selected a more even distribution of production plants, with plants also in the southern parts. Due to longer total transport distances and non-optimal integration possibilities, the total resulting system cost was higher when all counties must fulfil the biofuel share target. The total annual cost to fulfil a certain biofuel target would also be considerably higher without BLG in the system, as would the total capital requirement. This however presumes that alternative investments would otherwise be undertaken, such as investments in new recovery boilers. Without alternative investments the difference between a system with BLG and a system without BLG would be less pronounced.

    In several cases the model located two production plants very close to each other, which would create a high biomass demand on a limited geographic area. The reason is that no restrictions on transport volumes have yet been implemented in the model. Further, existing onsite co-operations between for example sawmills and pulp mills have not always been captured by the input data used for this report, which can cause the consideration of certain locations as two separate plant sites, when in reality they are already integrated. It is also important to point out that some of the mill specific data (obtained from the Swedish Forest Industries Federation’s environmental database) was identified to contain significant errors, which could affect the results related to the plant allocations suggested in this report.

    Due to the early model development stage and the exclusion of for example many potential production routes and feedstock types, the model results presented in this report must be considered as highly preliminary. A number of areas in need of supplementing have been identified during the work with this report. Examples are addition of more industries and plant sites (e.g. oil refineries), increasing the number of other production technologies and biofuels (e.g. SNG, biogas, methanol and synthetic diesel), inclusion of gas distribution infrastructures, and explicit consideration of import and export of biomass and biofuel. Agricultural residues and energy crops for biogas production are also considered to be a very important and interesting completion to the model. Furthermore, inclusion of intermediate products such as torrefied biomass, pyrolysis oil and lignin extracted from chemical pulp mills would make it possible to include new production chains that are currently of significant interest for technology developers. As indicated above, the quality of some input data also needs to be improved before any definite conclusions regarding next generation biofuel plant localisations can be drawn.Due to the early model development stage and the exclusion of for example many potential production routes and feedstock types, the model results presented in this report must be considered as highly preliminary. A number of areas in need of supplementing have been identified during the work with this report. Examples are addition of more industries and plant sites (e.g. oil refineries), increasing the number of other production technologies and biofuels (e.g. SNG, biogas, methanol and synthetic diesel), inclusion of gas distribution infrastructures, and explicit consideration of import and export of biomass and biofuel. Agricultural residues and energy crops for biogas production are also considered to be a very important and interesting completion to the model. Furthermore, inclusion of intermediate products such as torrefied biomass, pyrolysis oil and lignin extracted from chemical pulp mills would make it possible to include new production chains that are currently of significant interest for technology developers. As indicated above, the quality of some input data also needs to be improved before any definite conclusions regarding next generation biofuel plant localisations can be drawn.

    A further developed BeWhere Sweden model has the potential for being a valuable tool for simulation and analysis of the Swedish energy system, including the industry and transport sectors. The model can for example be used to analyse different biofuel scenarios and estimate cost effective biofuel production plant locations, required investments and costs to meet a certain biofuel demand. Today, concerned ministries and agencies base their analyses primary on results from the models MARKAL and EMEC, but none of these consider the spatial distribution of feedstock, facilities and energy demands. Sweden is a widespread country with long transport distances, and where logistics and localisation of production plants are crucial for the overall efficiency. BeWhere Sweden considers this and may contribute with valuable input that can be used to complement and validate results from MARKAL and EMEC; thus testing the feasibility of these model results. This can be of value for different biofuel production stakeholders as well as for government and policy makers. Further, Sweden is also of considerable interest for future next generation biofuel production from a European perspective. By introducing a link to existing models that operate on a European level, such as BeWhere Europe and the related IIASA model GLOBIOM, BeWhere Sweden could also be used to provide results of value for EU policies and strategies.

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    Optimal localisation of next generation biofuel production in Sweden
  • 42.
    Wilhelmsson, Ella
    Linköping University, Department of Thematic Studies, Tema Environmental Change.
    Investigations of the Effects of Lowering the Temperature in Full Scale Mesophilic Biogas Digesters at a Wastewater Treatment Plant2020Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This thesis has investigated the effects of running the two full scale biogas digesters at Slottshagen wastewater treatment plant at 34 °C compared to 37 °C, in terms of process stability, biogas production and energy savings with the aim of saving energy and money by not heating the digesters as much. The main objective was to investigate whether it is at all possible to operate the biogas process at 34 °C or if the process becomes inhibited or otherwise unstable. If the process could be operated at 34 °C it might mean savings of both energy and money, provided that there is still a sufficient production of biogas.The experiment lasted for three months and investigated the short-term effects of the reduction of temperature. The process was monitored closely, and samples from the reactors were collected and analysed twice a week to ensure the stability of the biogas process. Several parameters were monitored online, the biogas production and methane content amongst others. Other parameters were calculated, such as the degree of degradation and specific methane production. This was done to ensure process stability and a sufficient production of biogas. The energy balance was calculated to evaluate if energy was saved by lowering the temperature in the digesters.The results show that the biogas process does remain stable at 34 °C while still producing a satisfactory amount of biogas during the short time of the experiment. Calculations show that both energy and money has been saved during the experiment. However, the system is largely dependent on seasonal variations, therefore further studies over a longer time period would be desirable. During the course of the thesis it has also become evident that the biogas process at Slottshagen is irregular in several aspects, and that it would be beneficial to even the process out, especially with regards to the hydraulic retention time. Making the process more even would enable further improvements to be made and simplify interpretations and comparisons of processstability data.

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  • 43.
    Wrangbert, Marcus
    Linköping University, Department of Thematic Studies, Tema Environmental Change. Linköping University, Biogas Research Center.
    Counteracting Ammonia Inhibition in Anaerobic Digestion using Wood Residues: Evaluating Ammonium Adsorption Capacity of Fibres from Pulp and Paper Mills2021Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    One of the main interests in commercial methane production is to maximize the gas yield, and it is thus appealing to use material with relative high methane potential. However, such material often results in process instability whereas ammonia inhibition is common. Removal of ammonia through adsorption is a fairly unexplored method in the field of biogas production, and could prove to be cost-effective.The adsorption capacity of pulp fibres from the paper making industry were investigated through batch adsorption experiments. Additionally, the fibres effect on small scale batch digesters in terms of methane production and cellulase activity was explored. Overall, the adsorption capacity of the pulp fibres was low, whereas Kraft hardwood had the highest adsorption capacity in both an aqueous ammonium solution and digester fluid at 11±3 and 60±20 mg g-1, respectively. The initial total ammonium nitrogen concentration had the highest effect on the adsorption capacity with a positive correlation. The pulp fibres seemingly had no effect on the ammonia inhibited anaerobic digestion systems. However, the cellulase activity was higher after day 5 in the anaerobic digestion systems with a high ammonia concentration.In essence, the overall results showed that the adsorption of the fibres was relatively low and most likely not suitable as a material to prevent ammonia inhibition in an AD.

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