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  • 1.
    Amara, Sofiane
    et al.
    Unité de Recherche Matériaux et Energies Renouvelables (URMER) Université de Tlemcen, BP 119 Tlemcen, ALGERIA.
    Baghdadli, T
    Unité de Recherche Matériaux et Energies Renouvelables (URMER) Université de Tlemcen, BP 119 Tlemcen, ALGERIA.
    Nordell, Bo
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering. LTU.
    Planned Investigation of UTES Potential in Algeria2019In: Proceddings of the 2nd International Conference on Green Civil and Environmental Engineering (GCEE 2019) 4 - 6 September 2019, Atria Hotel Malang, Indonesia, 2019Conference paper (Other academic)
    Abstract [en]

    The unbalance between supply and demand of heat can be managed by thermal energy storage (TES). For large-scale systems the underground is used as storage medium or storage volume. Aquifer storage (ATES) is most suitable for very large applications, Borehole storage (BTES) the most general system in all scales and the rock cavern storage (CTES) is best suited for extremely high loading/extraction loads. The construction of any of these systems requires knowledge about site-specific properties of the ground i.e. geology and groundwater conditions. Current paper gives a brief review of the potential and advantage of CTES technology utilization in buildings for the hard climate.

  • 2.
    Carlsson, Isak
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Kartläggning och energieffektivisering: KV61, Gärstadverket Linköping2019Independent thesis Basic level (professional degree), 180 HE creditsStudent thesis
  • 3.
    Carvalho, Lara
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Opportunities to broaden biomass feedstocks in thermochemical conversion technologies2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Global environmental concerns are motivating a growing interest in broadening the biomass feedstock base in several energy sectors, including (i) the domestic heating sector, presently dominated by stem wood combustion, and (ii) biofuel production, presently dominated by edible crops. The objective of this thesis is to investigate new opportunities to broaden the biomass feedstock in thermochemical conversion technologies. The performance of different feedstocks was therefore investigated for (i) heat production in small-scale combustion systems and (ii) biofuel production in large-scale gasification-based plants. The selected feedstocks were agricultural residues, forest wood, pyrolysis liquid and industrial by-products, such as lignin, black liquor, crude glycerol and fermentation residues.

    The alkali metals content in biomass has an important role in combustion and gasification. Alkali metals can cause ash-related problems in small-scale combustion systems, while they can catalyse gasification reactions thus increasing conversion efficiency. Keeping this effect in mind, the present investigation was based on combustion tests with pelletised agricultural residues (non-woody feedstocks with ash contents of 3-8 wt% on a dry basis) to evaluate their combustion feasibility in several small-scale appliances. Moreover, the potential techno-economic benefits of alkali addition in gasification-based biofuel plants were investigated in two different systems: (i) stand-alone biofuel plant operated with wet-alkali-impregnated forest residues and alkali-rich lignin as well as (ii) biofuel plant integrated with a Kraft pulp mill operated with black liquor (an inherently alkali-rich feedstock) mixed with different blend ratios of pyrolysis liquid, crude glycerol or fermentation residues (co-gasification concept). The techno-economic analysis in large-scale entrained-flow-gasification-based biofuel plants was made with the help of simulation tools.

    The combustion tests have shown that high alkali feedstocks lead to problems with ash accumulation and slag formation in small-scale appliances. The results indicated that non-woody feedstocks can only be burned in appliances adapted to manage high ash content feedstocks. Effective ash cleaning and enhanced combustion controlling mechanisms are relevant characteristics to have in appliances when using these feedstocks. It has been shown that four out of the seven selected feedstocks can be burned in small-scale appliances, while fulfilling the legal European requirements (EN 303-5:2012) in terms of combustion efficiency and emissions. The nitrogen content and ash composition were shown to be important parameters to evaluate whether a feedstock can be utilised in small-scale combustion appliances.

    The techno-economic investigations of the gasification-based biofuel plants have shown that alkali impregnation is an attractive option to increase energy performance and downstream biofuel production. The economic assessment has indicated that alkali impregnation does not significantly increase biofuel production costs, while it allows the application of a new syngas cleaning system that can significantly reduce biofuel production costs. The present study has shown that the vi co-gasification concept has also techno-economic benefits as a result of the (i) alkali content in black liquor and (ii) economy-of-scale effects. These benefits can be enhanced by choosing energy-rich and low-cost blend-in feedstocks. The gasification-based biofuel production routes hereby investigated exhibit a good economic performance since biofuel required selling prices were economically competitive with other biofuel production routes as well as with taxed gasoline.

  • 4.
    Carvalho, Lara
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Furusjö, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. IVL – Swedish Environmental Institute, Stockholm, Sweden.
    Ma, Chunyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lundgren, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    Hedlund, Jonas
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Grahn, Mattias
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering, Chemical Engineering.
    Öhrman, Olov G. W.
    IVL – Swedish Environmental Institute, Stockholm, Sweden;RISE Energy Technology Center AB, Piteå, Sweden.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    Alkali enhanced biomass gasification with in situ S capture and a novel syngas cleaning: Part 2: Techno-economic analysis2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 165, no Part B, p. 471-482Article in journal (Refereed)
    Abstract [en]

    Previous research has shown that alkali addition has operational advantages in entrained flow biomass gasification and allows for capture of up to 90% of the biomass sulfur in the slag phase. The resultant low-sulfur content syngas can create new possibilities for syngas cleaning processes. The aim was to assess the techno-economic performance of biofuel production via gasification of alkali impregnated biomass using a novel gas cleaning systemcomprised of (i) entrained flow catalytic gasification with in situ sulfur removal, (ii) further sulfur removal using a zinc bed, (iii) tar removal using a carbon filter, and (iv) CO2 reductionwith zeolite membranes, in comparison to the expensive acid gas removal system (Rectisol technology). The results show that alkali impregnation increases methanol productionallowing for selling prices similar to biofuel production from non-impregnated biomass. It was concluded that the methanol production using the novel cleaning system is comparable to the Rectisol technology in terms of energy efficiency, while showing an economic advantagederived from a methanol selling price reduction of 2–6 €/MWh. The results showed a high level of robustness to changes related to prices and operation. Methanol selling prices could be further reduced by choosing low sulfur content feedstocks.

  • 5.
    Carvalho, Lara
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lundgren, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wolf, Jens
    RISE Bioeconomy.
    Furusjö, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Methanol production via black liquor co-gasification with expanded raw material base: Techno-economic assessment2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 225, p. 570-584Article in journal (Refereed)
    Abstract [en]

    Entrained flow gasification of black liquor combined with downstream-gas-derived synthesis of biofuels in Kraft pulp mills has shown advantages regarding energy efficiency and economic performance when compared to combustion in a recovery boiler. To further increase the operation flexibility and the profitability of the biofuel plant while at the same time increase biofuel production, black liquor can be co-gasified with a secondary feedstock (blend-in feedstock). This work has evaluated the prospects of producing biofuels via co-gasification of black liquor and different blend-in feedstocks (crude glycerol, fermentation residues, pyrolysis liquids) at different blend ratios. Process modelling tools were used, in combination with techno-economic assessment methods. Two methanol grades, crude and grade AA methanol, were investigated. The results showed that the co-gasification concepts resulted in significant increases in methanol production volumes, as well as in improved conversion efficiencies, when compared with black liquor gasification; 5-11 and 4-10 percentage point in terms of cold gas efficiency and methanol conversion efficiency, respectively. The economic analysis showed that required methanol selling prices ranging from 55-101 €/MWh for crude methanol and 58-104 €/MWh for grade AA methanol were obtained for an IRR of 15%. Blend-in led to positive economies-of-scale effects and subsequently decreased required methanol selling prices, in particular for low cost blend-in feedstocks (prices below approximately 20 €/MWh). The co-gasification concepts showed economic competitiveness to other biofuel production routes. When compared with fossil fuels, the resulting crude methanol selling prices were above maritime gas oil prices. Nonetheless, for fossil derived methanol prices higher than 80 €/MWh, crude methanol from co-gasification could be an economically competitive option. Grade AA methanol could also compete with taxed gasoline. Crude glycerol turned out as the most attractive blend-in feedstock, from an economic perspective. When mixed with black liquor in a ratio of 50/50, grade AA methanol could even be cost competitive with untaxed gasoline.

  • 6.
    Furusjö, Erik
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. IVL Swedish Environmental Research Institute, Climate & Sustainable Cities.
    Ma, Chunyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ji, Xiaoyan
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Carvalho, Lara
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Lundgren, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Alkali enhanced biomass gasification with in situ S capture and novel syngas cleaning: Part 1: Gasifier performance2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 157, p. 96-105Article in journal (Refereed)
    Abstract [en]

    Previous research shows that alkali addition in entrained flow biomass gasification can increase char conversion and decrease tar and soot formation through catalysis. This paper investigates two other potential benefits of alkali addition: increased slag flowability and in situ sulfur capture.

    Thermodynamic equilibrium calculations show that addition of 2–8% alkali catalyst to biomass completely changes the chemical domain of the gasifier slag phase to an alkali carbonate melt with low viscosity. This can increase feedstock flexibility and improve the operability of an entrained flow biomass gasification process. The alkali carbonate melt also leads to up to 90% sulfur capture through the formation of alkali sulfides. The resulting reduced syngas sulfur content can potentially simplify gas cleaning required for catalytic biofuel production.

    Alkali catalyst recovery and recycling is a precondition for the economic feasibility of the proposed process and is effected through a wet quench. It is shown that the addition of Zn for sulfur precipitation in the alkali recovery loop enables the separation of S, Ca and Mg from the recycle. For high Si and Cl biomass feedstocks, an alternative separation technology for these elements may be required to avoid build-up.

  • 7.
    Helmvall, Johanna
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Energilager i Luleå Energis elnät2019Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    This thesis will investigate possible energy storages in Luleå Energi’s power grid within a five-year period. The transition to a more sustainable and efficient energy system, in response to climate change, creates new challenges for the power grid. Energy storage has, according to many sources, the potential to contribute to meet the challenges that arise from a larger share of intermittent renewables, a growing number of electrical vehicles and increased demands for reliability and stability.

    Several reports conclude that currently energy storages are most profitable in customer applications, especially in combination with micro-production, e.g. solar cells. Therefore, this report will investigate if battery storages could be installed in three multi-residential properties with solar cells, with the purpose to increase self-use of electricity generated from the solar cells and peak-shaving. Batteries have been chosen as storage technology, since they currently seem to be the technology with the most potential. Possible savings for the customer as well as potential benefits for the grid will be considered.

    Based on data for the properties’ consumption and solar power production, an analysis has been made to see how much excess electricity the solar cells generate and to identify peak demands. Regarding the solar cells, data has only been available for a few months. For other days, the production has been estimated base on measurements of global radiation over Luleå municipality. A simulation in MATLAB has then been carried out to dimension the battery.

    When customers connect micro-production to the grid, the voltage may rise above permissible limits, especially in weaker rural grids. As a result, reinforcements of the grid may be necessary, which means expenses for the grid owner. Installation of a battery, that can store energy and keep the voltage within permissible limits, could be an alternative. The report considers such a case and makes a comparison between reinforcements of the grid and installation of a battery.  

    The results of the report show that energy storages have several potential benefits, both for customers, grid owners and system operators. Forecasts point to a strong growth, as well as lowered battery prices, which could lead to investments that are more profitable. The study of installing a battery in properties with solar cells shows that an increased self-use and peak shaving is possible. However, the economic results show negative net values. This means that currently the investment is not profitable. Approximately, battery prices must be cut in half to reach profitability. The calculation concludes that power tariffs enables most savings for the customers and gives them incentives for peak-shaving.

    The report also shows that the amount of micro-production in a rural grid can be limited by the strength of the grid. If five customers in the investigated part of the grid each would install 8.6 kW solar power, the voltage rise at the point of common coupling would go above permissible values, and the grid would have to be reinforced. The economical comparison between investing in new cables and installing a battery storage shows that currently, a battery storage is more expensive than a new cable.

    The overall conclusion from the report is that energy storage has the potential to contribute to the transition of the energy system. However, regulations and battery prices currently limit the possibilities for profitable investments. It is recommended to do an oversight of regulations and new business models to enable more investments in energy storage. Studying alternative tariffs is also important, to create incentives for a more efficient use of the power grid.

  • 8.
    Höltinger, Stefan
    et al.
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Schmidt, Johannes
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Using long term synthetic time series to assess the impact of meteorological extreme events on renewable energy systems: a case study of wind and hydro power in Sweden2017Conference paper (Other academic)
    Abstract [en]

    Synthetic time series of renewable energy generation provide important inputs for energy system models that study the transition to low carbon energy systems. The coverage of national energy statistics is usually too short or temporal resolution too low – in particular if meteorological extreme events should be assessed. These extreme events may put high stress on power systems with very high shares of renewables and therefore have to be studied in detail. We use simulated time series of Swedish wind energy generation for a 35 year period based on MERRA reanalysis datasets. The simulation of hydropower generation is more complex and requires hydrological models that combine precipitation data with spatially explicit information on soil type and land cover to simulate river discharge. For this purpose, we use time series of daily river discharge that have been simulated using the open source model HYPE (HYdrological Predictions for the Environment).

    We compared the derived time series for wind and hydropower generation in the four Swedish bidding areas with respect to their long-term correlation, patterns of seasonality, and length and duration of extreme events. Preliminary results show that expanding wind power capacities could significantly reduce the overall variability of renewable energy generation. Furthermore, the frequency and duration of extreme production events in a combined wind-hydropower system is lower than in a hydropower system only. Further work will study the need for backup capacities in a future Swedish power system with very high shares of hydro, wind and solar power (>90%).

  • 9.
    Höltinger, Stefan
    et al.
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Schmidt, Johannes
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Using long term synthetic time series to assess the impact of meteorological extreme events on renewable energy systems: a case study of wind and hydro power in Sweden2017In: Geophysical Research Abstracts, ISSN 1029-7006, E-ISSN 1607-7962, Vol. 19, article id EGU2017-14131Article in journal (Other academic)
    Abstract [en]

    Synthetic time series of renewable energy generation provide important inputs for energy system models that study the transition to low carbon energy systems. The coverage of national energy statistics is usually too short or temporal resolution too low – in particular if meteorological extreme events should be assessed. These extreme events may put high stress on power systems with very high shares of renewables and therefore have to be studied in detail. We use simulated time series of Swedish wind energy generation for a 35 year period based on MERRA reanalysis datasets. The simulation of hydropower generation is more complex and requires hydrological models that combine precipitation data with spatially explicit information on soil type and land cover to simulate river discharge. For this purpose, we use time series of daily river discharge that have been simulated using the open source model HYPE (HYdrological Predictions for the Environment).

    We compared the derived time series for wind and hydropower generation in the four Swedish bidding areas with respect to their long-term correlation, patterns of seasonality, and length and duration of extreme events. Preliminary results show that expanding wind power capacities could significantly reduce the overall variability of renewable energy generation. Furthermore, the frequency and duration of extreme production events in a combined wind-hydropower system is lower than in a hydropower system only. Further work will study the need for backup capacities in a future Swedish power system with very high shares of hydro, wind and solar power (>90%).

  • 10.
    Jafri, Yawer
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Biofuels from Kraft Black Liquor: Pilot-Scale Gasification Development and Techno-Economic Evaluation of Industrially Relevant Biofuel Production Pathways2019Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Fuel combustion for transport was responsible for 24% of EU-28 greenhouse gas (GHG) emissions in 2016. Member states are expected to ensure that the share of renewable energy in the transport sector is at least 14% by 2030. Some countries, such as Sweden, have more ambitious targets. By 2030, GHG emissions from domestic transport are to be reduced by 70% relative to 2010 levels. A national emission reduction scheme launched in 2018 obliges suppliers of diesel and petrol to reduce their GHG footprints annually by a pre-determined amount, which could further stimulate demand for drop-in biofuels, and potentially even high blend alternatives. However, recent changes to Swedish domestic policy and the EU-wide RED sustainability criteria mean that biodiesel from some common crop-based biomaterials may no longer qualify for certain important tax benefits or count towards the 2030 renewables target. Given Sweden’s extensive forest products industry, woody residue and by-products, such as branches, toppings and black liquor (BL) are viewed as strategically important feedstock for the production of RED-compliant biofuels. Upgrading kraft BL to biofuels can also potentially help pulp mills expand their product base. Two conversion routes are seen as industrially relevant in the short-to-medium term: (a) gasification-catalytic synthesis, (b) liquefaction-hydrotreatment.

    The production of methanol and dimethyl ether from kraft BL has been demonstrated extensively in a pilot facility, although a complete analysis of technical performance based on experimental measurements has not been performed previously. Since BL is not transportable, the biofuel production potential of a mill is effectively set by its pulp throughput, which limits potential economies-of-scale. BL is rich in catalytically active sodium compounds and blending it with other woody residue-based feedstock, such as pyrolysis oil (PO) before gasification allows the partial decoupling of biofuel production capacity from available black liquor volumes. Several commercial actors are currently testing the technical viability of using liquefaction-hydrotreatment for the production of renewable petrol and diesel blendstock from kraft lignin. The first step in both cases is co-located at a pulp mill. Depending on the desired end product and production route, subsequent upgrading and finishing may be carried out at a pulp mill or a crude oil refinery, with a resulting impact on both production economics and energetic performance that is complex and little studied. 

    The main aim of this thesis is to evaluate the technical and economic viability of kraft liquor-based biofuel production pathways that are adjudged to be commercially relevant, that is they are seen as commercially deployable in the short-to-medium term at the present time. The catalytic co-gasification of PO and BL was studied in pilot-scale experiments, and resulting data were used to calculate key performance indicators. Blending BL with the more energy-rich PO led to an increase in cold gas efficiency without adversely affecting organic carbon conversion, which remained nearly complete at blend ratios of up to 20 wt.% PO. There were no signs of an increase in either soot or tar formation. Analyses of gas condensate samples found traces of unknown uncharged forms of sulfur and while sulfur reduction efficiencies were generally high, balance closures could not consistently be obtained owing to analytical difficulties. Further study appears warranted. Pilot-scale entrained-flow gasification experiments are expensive and time consuming. An alternative is thermodynamic equilibrium calculations, which were found to predict the flows of major syngas and slag constituents with a high degree of accuracy, subject to expected deviations in methane formation and sulfur distribution.

    An analysis of production economics found nth-of-a-kind investments in gasification-based methanol and lignin liquefaction and hydrotreatment-based drop-in biofuels to be profitable for a range of sizes, although the latter pathway, which is currently prioritized for development in the short-run was at a lower level of technology maturity. In assessing the overall energetic performance of a pulp mill-integrated kraft BL-based biofuel production, explicit consideration of mill energy balance is needed to avoid misestimation. Modern market pulp mills with a large energy surplus, normally exported as electricity, are at an advantage. There are indications that relatively small gasification units of around 100 MW could potentially also be profitable, which means biofuel production facilities based on both principle conversion tracks could be used to debottleneck pulp production by relieving recovery boiler capacity constraints, although the viability of such an approach is mill specific and requires detailed investigation. While co-gasifying black liquor with pyrolysis oil or blending syngas from unblended black liquor with electrolysis hydrogen offers better carbon utilization, larger biofuel production potentials and a more diverse feedstock base, gasification of unblended black liquor comes out as the lowest cost option for producing drop-in biofuels from part-streams. 

  • 11.
    Jafri, Yawer
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Mesfun, Sennai Asmelash
    Rådberg, Henrik
    Mossberg, Johanna
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Hulteberg, Christian
    Furusjö, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Combining Expansion in Pulp Capacity with Production of Sustainable Biofuels – Techno-economic and GHG emission assessment of Drop-in Fuels from Black Liquor Part-StreamsManuscript (preprint) (Other academic)
    Abstract [en]

    Drop-in biofuels produced from forestry by-products such as black liquor (BL) can help achieve deep reductions in transport GHG emissions. Upgrading kraft BL to drop-in biofuels can also help pulp mills increase pulp production and expand their product base, especially if the technical and economic risk associated with recovery boiler replacement can be mitigated. The economic and GHG performance of two lignin-based pathways and three gasification-based pathways is examined. All of these pathways can be used to debottleneck recovery boiler-limited pulp mills by converting black liquor part-stream to drop-in biofuels, with final processing in crude oil refineries, which is poorly investigated in the literature. Process modelling was carried out using best available technical data to estimate biofuel yields, estimate GHG footprints and determine biofuel production costs.

    Results show that the lignin route and the gasification have comparable production costs of ∼ 80 EUR2017 in the best case. One yields diesel as the primary biofuel product, while the other produces petrol and LPG. Mill that have an energy surplus that is normally exported as electricity have an advantage as biofuel integration sites over mills with no or negative surplus. All of the examined pathways can meet or exceed RED II criteria for GHG emission savings from new plants. Within the lignin route, the use of natural gas as hydrogen source represents the cheaper option by some margin, but GHG savings from the electrolysis-hydrogen alternative are considerably greater. The use of pyrolysis oil and electrolysis hydrogen as secondary feeds can improve the efficiency of biofuel production and generate larger biofuel yields from the same amount of black liquor. However, the high price of pyrolysis oil and the high investment cost of PEM electrolysis makes the BLG+electrolysis and BLG+pyrolysis alternatives more expensive than the gasification of unblended black liquor.

  • 12.
    Krook Riekkola, Anna
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Sandberg, Erik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Biomassa, systemmodeller och målkonflikter2017Report (Refereed)
    Abstract [en]

    The availability and competition for woody biomass has been analysed with a district heating perspective with an aim to contribute to a broader system understanding of the interaction between the district heating system, the forest biomass system and the biofuel system. The starting point has been two energy system models that in different ways capture the competition for biomass in Sweden. The focus has been on (1) identifying possible conflicting targets between increased electricity generation from district heating, increased biofuel production and reduced carbon dioxide emissions, and (2) identifying how the models can communicate and be further developed in order to improve the representation of biomass in the national energy system analysis.

  • 13.
    Krook-Riekkola, Anna
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Bilaga 12: Klimatmålsanalys med TIMES-Sweden: Övergripande klimatmål 2045 i kombination med sektormål 20302016In: En klimat- och luftvårdsstrategi för Sverige: delbetänkande / av Miljömålsberedningen, Stockholm: Wolters Kluwer, 2016, p. 429-454Chapter in book (Other academic)
  • 14.
    Krook-Riekkola, Anna
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Berg, Charlotte
    National Institute of Economic Research (NIER), Stockholm, Sweden.
    Ahlgren, Erik
    Chalmers University of Technology, Department of Energy and Environment.
    Söderholm, Patrik
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Challenges in top-down and bottom-up soft linking: Lessons from linking a Swedish energy system model with a CGE model2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 141, p. 803-817Article in journal (Refereed)
    Abstract [en]

    This paper proposes and discusses a soft-linking procedure between a Computable General Equilibrium (CGE) model and an energy system model with the aim to improve national energy policy decision-making. Significant positive and negative experiences are communicated. Specifically, the process of soft-linking the EMEC and TIMES-Sweden models is presented, and unlike previous work we rely on the use of multiple direction-specific connection points. Moreover, the proposed soft-linking methodology is applied in the context of a climate policy scenario for Sweden. The results display a partly new description of the Swedish economy, which when soft-linking, generates lower CO2-emissions in the reference scenario due to a decline in industrial energy demand. These findings point at the importance of linking bottom-up and top-down models when assessing national energy and climate policies.

  • 15.
    Lundmark, Robert
    et al.
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Forsell, Nicklas
    International Institute for Applied Systems Analysis.
    Leduc, Sylvain
    International Institute for Applied Systems Analysis.
    Lundgren, Joakim
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ouraich, Ismail
    Luleå University of Technology, Department of Business Administration, Technology and Social Sciences, Social Sciences.
    Pettersson, Karin
    Rise.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Large-scale implementation of biorefineries: New value chains, products and efficient biomass feedstock utilisation2018Report (Other (popular science, discussion, etc.))
  • 16.
    Ma, Charlie
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Carlborg, Markus
    Energy Technology and Thermal Process Chemistry, Department of Applied Physics and Electronics, Umeå University.
    Hedman, Henry
    SP Energy Technology Center AB.
    Wennebro, Jonas
    SP Energy Technology Center AB.
    Weiland, Fredrik
    SP Energy Technology Center AB.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. SP Energy Technology Center AB.
    Backman, Rainer
    Energy Technology and Thermal Process Chemistry, Department of Applied Physics and Electronics, Umeå University.
    Öhman, Marcus
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Ash Formation in Pilot-Scale Pressurized Entrained-Flow Gasification of Bark and a Bark/Peat Mixture2016In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 30, no 12, p. 10543-10554Article in journal (Refereed)
    Abstract [en]

    Pressurized entrained-flow gasification (PEFG) of bark and a bark/peat mixture (BPM) was carried out in a pilot-scale reactor (600 kWth, 7 bar(a)) with the objective of studying ash transformations and behaviors. The bark fuel produced a sintered but nonflowing reactor slag, while the BPM fuel produced a flowing reactor slag. Si was enriched within these slags compared to their original fuel ash compositions, especially in the bark campaign, which indicated extensive ash matter fractionation. Thermodynamically, the Si contents largely accounted for the differences in the predicted solidus/liquidus temperatures and melt formations of the reactor slags. Suspension flow viscosity estimations were in qualitative agreement with observations and highlighted potential difficulties in controlling slag flow. Quench solids from the bark campaign were mainly composed of heterogeneous particles resembling reactor fly ash particles, while those from the BPM campaign were flowing slags with likely chemical interactions with the wall refractory. Quench effluents and raw syngas particles were dominated by elevated levels of K that, along with other chemical aspects, indicated KOH(g) and/or K(g) were likely formed during PEFG. Overall, the results provide information toward development of woody biomass PEFG and indicate that detailed understanding of the ash matter fractionation behavior is essential.

  • 17.
    Nilsson, Erik A. A.
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Hedman, Henry
    ETC Piteå.
    Wiinikka, Henrik
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. ETC.
    Antti, Marta-Lena
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Material Science.
    Simultaneous deposition and erosion of iron ore particles in a 300 kW combustion kilnIn: Open Energy and Fuels Journal, ISSN 1874-2483Article in journal (Refereed)
  • 18.
    Nwachukwu, Chinedu M
    et al.
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Toffolo, Andrea
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Grip, Carl-Erik
    Wang, Chuan
    Swerea MEFOS, Process Integration Department.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science.
    Systems analysis of sawmill by-products gasification towards a bio-based steel production2018In: ECOS 2018: Proceedings of the 31st International Conference on Efficiency, Cost, Optimisation, Simulation and Environmental Impact of Energy Systems / [ed] José Carlos Teixeira, Ana Cristina Ferreira, Ângela Silva, Senhorinha Teixeira, Universidade do Minho. Departamento de Engenharia Mecânica Campus Azurém, Guimarães Portugal , 2018Conference paper (Refereed)
  • 19.
    Schmidt, Johannes
    et al.
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Gruber, Katharina
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Klingler, Michael
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.Department of Geography, University of Innsbruck, Austria.
    Klöckl, Claude
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Camargo, Luis Ramirez
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    Regner, Peter
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Turkovska, Olga
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Wehrle, Sebastian
    Institute for Sustainable Economic Development, University of Natural Resources and Life Sciences, Vienna, Austria.
    Wetterlund, Elisabeth
    Luleå University of Technology, Department of Engineering Sciences and Mathematics, Energy Science. International Institute for Applied Systems Analysis (IIASA), Laxenburg, Austria.
    A new perspective on global renewable energy systems: why trade in energy carriers matters2019In: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 12, no 7, p. 2022-2029Article in journal (Refereed)
    Abstract [en]

    Recent global modelling studies suggest a decline of long-distance trade in energy carriers in future global renewable energy systems, compared to today's fossil fuel based system. In contrast, we identify four drivers that facilitate trade of renewable energy carriers. These drivers may lead to trade volumes remaining at current levels or even to an increase during the transition to an energy system with very high shares of renewables. First, new land-efficient technologies for renewable fuel production become increasingly available and technically allow for long-distance trade in renewables. Second, regional differences in social acceptance and land availability for energy infrastructure support the development of renewable fuel import and export streams. Third, the economics of renewable energy systems, i.e. the different production conditions globally and the high costs of fully renewable regional electricity systems, will create opportunities for spatial arbitrage. Fourth, a reduction of stranded investments in the fossil fuel sector is possible by switching from fossil fuels to renewable fuel trade. The impact of these drivers on trade in renewable energy carriers is currently under-investigated by the global energy systems research community. The importance of the topic, in particular as trade can redistribute profits and losses of decarbonization and may hence support finding new partners in climate change mitigation negotiations, warrants further research efforts in this area therefore.

  • 20.
    Schylander, Anna
    Luleå University of Technology, Department of Civil, Environmental and Natural Resources Engineering.
    Building-Integrated Photovoltaics for a Habitat on Mars: A Design Proposal Based on the Optimal Location and Placement of Integrated Solar Cells2019Independent thesis Advanced level (professional degree), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The ever-increasing challenges that we face with our consumption of resources on Earth are factors which have prompted researchers to show interest in studying the possibilities of human habitat on other celestial bodies. Mars is a stone planet and is at such distance from the sun that it could be feasible for future settlements with the right technology and solutions. Future missions to Mars rely on solar panels as their primary power system. Utilizing solar architecture is a solution that reduces both a building’s energy consumption and the extent of environmental damage fossil fuels are causing the Earth. This leads to extensive opportunities to explore how we can increase the use of renewable energy using new technologies developed for use on Earth but also for use in the space industry.

     

    This study used a qualitative method through literature studies and semi-structured interviews as well as a quantitative method through calculations. The literature study was meant to act as a theoretical base for this study and for the interviews by creating an understanding of the world’s usage of renewable and non-renewable energy sources and how solar power works by the means of photovoltaic cells. The interviews were held to identify the opportunities and obstacles regarding a solar power system on Mars as well as the usage of BIPV (building-integrated photovoltaics) in extreme environments. Mathematical calculations were based on the fundamental geometric shape of a cylinder where the walls were set to be the varying parameter. Six locations on Mars with different coordinates and underlying matters were selected to the study based on the knowledge collected from the literature study and the interviews.

     

    Aspects that needs to be considered for building-integrated photovoltaics placed on a building’s envelope on Mars are several. Some of the most crucial are: dust deposition and dust in the atmosphere, a climate with major temperature extremes, the habitats location on the planet and the amount of output energy provided by BIPV partly affected by the Mars-Sun distance. If the fundamental geometric shape of the building is a cylinder, the building’s shape would to form as a truncated cone with smaller wall slopes the closer the equator the habitat is located. If the habitat is placed far away from the equator the walls’ slope, the optimal tilt angle of the photovoltaic module, would be steeper and increase with the higher latitude. The maximized power by using BIPV on a building on Mars is provided as close to the equator as possible due to the big amount of sunlight reaching the surface. If BIPV could be used on the Martian surface is still a relatively extensive hypothesis. Studies about Mars and other planets tend to result in this kind of approach because of the many insecurities that cannot be proven before humans get to the planet or detailed tests have been accomplished and analyzed. A solar power system shows great opportunities for future human missions to Mars but BIPV is not considered an option in the near future without further research and development verifying the option.

  • 21.
    Svartsjaern, Emma
    Luleå University of Technology, Department of Engineering Sciences and Mathematics.
    Ö-drift av ett stugområde med förnyelsebar energi i Luleå skärgård2018Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Examensarbetet innefattade ekonomiska beräkningar gällande införskaffande av sol- samt vindkraftsproduktion för en ö i Luleå skärgård som fungerar vid ö-drift gentemot kostnaden för att flyga ut ett reservaggregat i tre delar med helikopter. En förenklad kostnadskalkyl utfördes gällande investering samt underhåll för den förnyelsebara elproduktionen och dess nuvärde sett till 25-års livslängd för vindkraft såväl som solkraft. Detta vägdes mot utgifterna för utflygning av ett reservaggregat med helikopter som är den reservkraftslösning som finns att tillgå i dagsläget.

    Beräkningar av kortslutningseffekt med den förnyelsebara produktionen och hur det påverkar felbortkopplingar samt spänningsnivåer togs också med.

    Den ekonomiska investeringen kom också att vägas mot kundnyttan i form av ökad trygghetskänsla med en färdig reservkraftslösning samt fortsatt utveckling för företaget inom förnyelsebar energi.

    Uppdraget begränsades till att innefatta två olika scenarion med förnyelsebar energi, ett med 100 % solkraft och ett med cirka 10 kW vindkraft och 35 kW solkraft. Solcellssystemet kom att vara fristående på markställning vriden direkt mot söder med lämplig vinkling på solcellspanelerna. För scenarierna användes färdiga produktionslösningar samt färdiga batterilösningar för att behålla visst överskott av produktion till senare behov samt ett nät med nog låg spänningsvariation samt hög frekvensstabilitet under kortare tid. Kortare tid i detta fall gällde mellan 3 timmar upp till 3 veckor.

    Projektet tog effektbehovsdata samt möjliga meteorologiska data från en ö i Luleå Skärgård som ligger i skärgårdsnätet. Där fanns det 38 kunder där majoriteten hade kraftbehov under årets varmare månader, med några få kunder som var där nästan året runt. Ön kommer hädanefter refereras till som driftplatsen i rapporten. Den meteorologiska data som ej fanns att tillgå på driftplatsen togs vid närmaste väderstation, i detta fall Luleå stad.

    Sett till instrålningsdata samt avlästa vindhastigheter visade det sig att en produktionsanläggning med endast solcellspaneler och minst 12 h batteribank inte var realistisk som reservkraftlösning vid möjlig ö-drift vintertid. En större batteribank på 3 dygns försörjning skulle inte vara ekonomiskt försvarbar jämfört med investeringskostnaden till produktionsanläggningen, och det skulle trots det inte avhjälpa de produktionsproblem som var aktuella under vinterhalvåret.

    En kombination av solkraft och vindkraft med 3h batteriförsörjning kompletterade varandra väl till effektbehoven som återfanns på driftplatsen, klarade av de kraven som ställdes gällande variation i spänning och möjliga överströmmar samt skulle möjliggöra elförsörjning året runt.

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