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  • 1.
    Ali, Sharafat
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Melting Characteristics and Morphology of Bottom Ash and Filter Ash of the Circulating Fluidized Bed Boiler2013In: 21st European Biomass Conference and Exhibition, Copenhagen, Danmark, 3rd-7th June, 2013, ETA-Florence Renewable Energies , 2013, p. 1189-1191Conference paper (Refereed)
    Abstract [en]

    The aim of this work was to investigate the melting characteristics and morphology of filter ash and bottom ash with and without 7% of peat addition to the fuel of the circulating fluidized bed boiler. The samples were characterized by simultaneous thermal analysis (STA) and scanning electron microscope (SEM). The STA results indicate that the filter ash melts at 1140oC with 10 wt% of the mass loss and Bottom ash partially melts at 1170oC with below 2 wt% of the mass loss. The low melting point of the filter ash is due to the high concentration of the alkali metals in the filter ash. Similar trends were observed in the case of fly ash and bottom ash with peat admixture to the fuel. Furthermore the elementary analysis via scanning electron microscopy, coupled with energy-dispersive X-ray analysis showed that 7% of peat addition to the fuel does not significantly effect on the ash composition.

  • 2.
    Bennani, Mohamed
    Linnaeus University, Faculty of Technology, Department of Informatics.
    Smarter technologies towards Greener Homes: A Human-Centred Approach2018Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Advances in technology continuously reshape habits, behaviours and interactions at individual, organisational and societal levels. Information and Communication technology (ICT) is pervasive, and is the bearer of crucial information, analysis and responses to the recipient. It assists in processes such as understanding phenomena and taking appropriate action. It also provides communication means, platforms and tools to interact with one another.

    In the United Kingdom’s (UK) Energy industry, smart meters are currently being deployed by energy suppliers to their customers. These are presented as a revolutionary device that supports a more efficient energy use at home and/or in the workplace, and helps customers save on their energy bill and reduce carbon footprint.

    Using interpretivist phenomenological Human-centred qualitative research, The thesis work explores the impact of using smart meter devices, as perceived by UK customers, in helping to monitor, use and manage energy consumption at home. Also, the study looks into alternative technology and customers’ expectations in the context of energy efficiency. And finally, the principles of a design is presented to respond to customers demands and desires. Passive participant observation, Future workshop and inspiration cards session are the methods and techniques applied in this research to collect  data.

    The findings constitute good grounds for individual consumers to be aware of the opportunities made available by alternative technology. At organisational level it is a basis for energy suppliers to change their behaviour towards a changing demand and adapt by switching their core business to supplying Information and analysis as well as energy efficiency management solutions. At societal level government bodies and regulating agencies can tackle sustainability and green energy issues by controlling the profit driven character of privatised energy companies and responding to real market demand as perceived by consumers.

    Emerging technologies present opportunities that have the capabilities of breaking the status quo of energy supply industry in the UK as well as the rest of world.

    The value of this research is to show customers’ perceived reality and expectations, as well as opportunities to change the way energy is supplied and consumed.

  • 3.
    Bonakdar, Farshid
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Cost-optimum analysis of building fabric renovation in a Swedish multi-story residential building2014In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 84, p. 662-673Article in journal (Refereed)
    Abstract [en]

    In this study, we analysed the cost-optimum level of building fabric elements renovation in a multi-story residential building. We calculated final energy use for space heating of the building considering a wide range of energy efficiency measures, for exterior walls, basement walls, attic floor and windows. Different extra insulation thicknesses for considered opaque elements and different U-values for new windows were used as energy efficiency measures. We calculated difference between the marginal saving of energy cost for space heating and the investment cost of implemented energy efficiency measures, in order to find the cost-optimum measure for each element. The implications of building lifespans, annual energy price increase and discount rate on the optimum measure were also analysed. The results of the analysis indicate that the contribution of energy efficiency measures to the final energy use reduces, significantly, by increasing the thickness of extra insulation and by reducing the U-value of new windows. We considered three scenarios of business as usual (BAU), intermediate and sustainability, considering different discount rates and energy price increase. The results of this analysis suggest that the sustainability scenario may offer, approximately, 100% increase in the optimum thickness of extra insulation compare to BAU scenario. However, the implication of different lifespans of 40, 50 or 60 years, on the optimum measure appears to be either negligible or very small, depending on the chosen scenario. We also calculated the corresponding U-value of the optimum measures in order to compare them with the current Swedish building code requirements and passive house criteria. The results indicate that all optimum measures meet the Swedish building code. None of the optimum measures, however, meet the passive house criteria in BAU scenario. This study suggests that the employed method of building renovation cost-optimum analyses can be also applied on new building construction to find the cost-optimum design from energy conservation point of view.

  • 4.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Hulteberg, Christain
    Kusar, Henrik
    Kungliga tekniska högskolan.
    A review of thermo-chemical conversion of biomass into biofuels: focusing on gas cleaning and up-grading process steps2017Report (Other (popular science, discussion, etc.))
    Abstract [en]

    It is not easy to replace fossil-based fuels in the transport sector, however, an appealing solution is to use biomass and waste for the production of renewable alternatives. Thermochemical conversion of biomass for production of synthetic transport fuels by the use of gasification is a promising way to meet these goals.

    One of the key challenges in using gasification systems with biomass and waste as feedstock is the upgrading of the raw gas produced in the gasifier. These materials replacing oil and coal contain large amounts of demanding impurities, such as alkali, inorganic compounds, sulphur and chlorine compounds. Therefore, as for all multi-step processes, the heat management and hence the total efficiency depend on the different clean-up units. Unfortunately, the available conventional gas filtering units for removing particulates and impurities, and also subsequent catalytic conversion steps have lower optimum working temperatures than the operating temperature in the gasification units.

    This report focuses on on-going research and development to find new technology solutions and on the key critical technology challenges concerning the purification and upgrading of the raw gas to synthesis gas and the subsequent different fuel synthesis processes, such as hot gas filtration, clever heating solutions and a higher degree of process integration as well as catalysts more resistant towards deactivation. This means that the temperature should be as high as possible for any particular upgrading unit in the refining system. Nevertheless, the temperature and pressure of the cleaned synthesis gas must meet the requirements of the downstream application, i.e. Fischer-Tropsch diesel or methanol.

    Before using the gas produced in the gasifier a number of impurities needs to be removed. These include particles, tars, sulphur and ammonia. Particles are formed in gasification, irrespective of the type of gasifier design used. A first, coarse separation is performed in one or several cyclone filters at high temperature. Thereafter bag-house filters (e.g. ceramic or textile) maybe used to separate the finer particles. A problem is, however, tar condensation in the filters and there is much work performed on trying to achieve filtration at as high a temperature as possible.

    The far most stressed technical barriers regarding cleaning of the gases are tars. To remove the tar from the product gas there is a number of alternatives, but most important is that the gasifier is operated at optimal conditions for minimising initial tar formation. In fluid bed and entrained flow gasification a first step may be catalytic tar cracking after particle removal. In fluid bed gasification a catalyst, active in tar cracking, may be added to the fluidising bed to further remove any tar formed in the bed. In this kind of tar removal, natural minerals such as dolomite and olivine, are normally used, or catalysts normally used in hydrocarbon reforming or cracking. The tar can be reformed to CO and hydrogen by thermal reforming as well, when the temperature is increased to 1300ºC and the tar decomposes. Another method for removing tar from the gas is to scrub it by using hot oil (200-300ºC). The tar dissolves in the hot oil, which can be partly regenerated and the remaining tar-containing part is either burned or sent back to the gasifier for regasification.

    Other important aspects are that the sulphur content of the gas depends on the type of biomass used, the gasification agent used etc., but a level at or above 100 ppm is not unusual. Sulphur levels this high are not acceptable if there are catalytic processes down-stream, or if the emissions of e.g. SO2 are to be kept down. The sulphur may be separated by adsorbing it in ZnO, an irreversible process, or a commercially available reversible adsorbent can be used. There is also the possibility of scrubbing the gas with an amine solution. If a reversible alternative is chosen, elementary sulphur may be produced using the Claus process.

    Furthermore, the levels of ammonia formed in gasification (3,000 ppm is not uncommon) are normally not considered a problem. When combusting the gas, nitrogen or in the worst case NOx (so-called fuel NOx) is formed; there are, however, indications that there could be problems. Especially when the gasification is followed by down-stream catalytic processes, steam reforming in particular, where the catalyst might suffer from deactivation by long-term exposure to ammonia.

    The composition of the product gas depends very much on the gasification technology, the gasifying agent and the biomass feedstock. Of particular significance is the choice of gasifying agent, i.e. air, oxygen, water, since it has a huge impact on the composition and quality of the gas, The gasifying agent also affects the choice of cleaning and upgrading processes to syngas and its suitability for different end-use applications as fuels or green chemicals.

    The ideal upgraded syngas consists of H2 and CO at a correct ratio with very low water and CO2 content allowed. This means that the tars, particulates, alkali salts and inorganic compounds mentioned earlier have to be removed for most of the applications. By using oxygen as the gasifying agent, instead of air, the content of nitrogen may be minimised without expensive nitrogen separation.

    In summary, there are a number of uses with respect to produced synthesis gas. The major applications will be discussed, starting with the production of hydrogen and then followed by the synthesis of synthetic natural gas, methanol, dimethyl ether, Fischer-Tropsch diesel and higher alcohol synthesis, and describing alternatives combining these methods. The SNG and methanol synthesis are equilibrium constrained, while the synthesis of DME (one-step route), FT diesel and alcohols are not. All of the reactions are exothermal (with the exception of steam reforming of methane and tars) and therefore handling the temperature increase in the reactors is essential. In addition, the synthesis of methanol has to be performed at high pressure (50-100 bar) to be industrially viable.

    There will be a compromise between the capital cost of the whole cleaning unit and the system efficiency, since solid waste, e.g. ash, sorbents, bed material and waste water all involve handling costs. Consequently, installing very effective catalysts, results in unnecessary costs because of expensive gas cleaning; however the synthesis units further down-stream, especially for Fischer-Tropsch diesel, and DME/methanol will profit from an effective gas cleaning which extends the catalysts life-time. The catalyst materials in the upgrading processes essentially need to be more stable and resistant to different kinds of deactivation.

    Finally, process intensification is an important development throughout chemical industries, which includes simultaneous integration of both synthesis steps and separation, other examples are advanced heat exchangers with heat integration in order to increase the heat transfer rates. Another example is to combine exothermic and endothermic reactions to support reforming reactions by using the intrinsic energy content. For cost-effective solutions and efficient application, new solutions for cleaning and up-grading of the gases are necessary.

  • 5.
    Brandin, Jan
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Odenbrand, Ingemar
    Lund University .
    Poisoning of SCR Catalysts used in Municipal Waste Incineration Applications2017In: Topics in catalysis, ISSN 1022-5528, E-ISSN 1572-9028, Vol. 60, no 17-18, p. 1306-1316Article in journal (Refereed)
    Abstract [en]

    A commercial vanadia, tungsta on titania SCRcatalyst was poisoned in a side stream in a waste incinerationplant. The effect of especially alkali metal poisoningwas observed resulting in a decreased activity at long timesof exposure. The deactivation after 2311 h was 36% whilethe decrease in surface area was only 7.6%. Thus the majorcause for deactivation was a chemical blocking of acidicsites by alkali metals. The activation–deactivation modelshowed excellent agreement with experimental data. Themodel suggests that the original adsorption sites, fromthe preparation of the catalyst, are rapidly deactivated butare replaced by a new population of adsorption sites dueto activation of the catalyst surface by sulphur compounds(SO2, SO3)in the flue gas.

  • 6. Bäck, Andreas
    et al.
    Grubbström, Jörgen
    Ecke, Holger
    Pettersson, Jens
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Strand, Michael
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Operation of an Electroctrostatic Precipitator at a 30 MWth oxyfuel plant2011Conference paper (Other academic)
    Abstract [en]

    The performance of a full-scale ESP was studied at the Vattenfall AB oxyfuel pilot plant in SchwarzePumpe. The lignite-fired boiler has a 30 MWth top-mounted pulverized coal burner and was operated under conventional air combustion as well as oxyfuel combustion. The ESP was operated with varying numbers of fields in service and at different current/voltage settings. Particle number size distributionsdownstream the ESP were established on-line in the size range 0.015-10 μm, using an electrical mobility spectrometer and an aerodynamic particle sizer. The particle size distribution at oxyfuel operation was qualitatively very similar to the results obtained for air-firing. Gravimetric measurementsof total fly ash concentration showed outlet emissions below 5 mg/Nm3 when the ESP was operatedwith two fields in service at oxyfuel conditions.

  • 7.
    Carlsson, Bo
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Meir, Michaela
    Aventa AS, Norway.
    Rekstad, John
    Aventa AS, Norway.
    Preiss, Dieter
    AEE-INTEC, Austria.
    Ramschak, Thomas
    AEE-INTEC, Austria.
    Replacing traditional materials with polymeric materials in solar thermosiphon systems: Case study on pros and cons based on a total cost accounting approach2016In: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 125, p. 294-306Article in journal (Refereed)
    Abstract [en]

    The pros and cons of replacing traditional materials with polymeric materials in solar thermosiphon systems were analysed by adopting a total cost accounting approach.

    In terms of climatic and environmental performance, polymeric materials reveal better key figures than traditional ones like metals. In terms of present value total cost of energy, taking into account functional capability, end user investment cost, O&M cost, reliability and climatic cost, the results suggest that this may also be true when comparing a polymeric based thermosiphon system with a high efficient thermosiphon system of conventional materials for DHW production in the southern Europe regions. When present values for total energy cost are assessed for the total DHW systems including both the solar heating system and the auxiliary electric heating system, the difference in energy cost between the polymeric and the traditional systems is markedly reduced.

    The main reason for the difference in results can be related to the difference in thermal performance between the two systems. It can be concluded that the choice of auxiliary heating source is of utmost importance for the economical competiveness of systems and that electric heating may not be the best choice.

  • 8.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effect of energy efficiency requirements for residential buildings in Sweden on lifecycle primary energy use2014In: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014 / [ed] Yan, J; Lee, DJ; Chou, SK; Desideri, U; Li, H, Elsevier, 2014, p. 1183-1186Conference paper (Refereed)
    Abstract [en]

    In this study we analyze the lifecycle primary energy use of a wood-frame apartment building designed to meet the current Swedish building code or passive house criteria, and heated with district heat or bedrock heat pump. We employ a lifecycle perspective methodology and determine the production, operation and end-of-life primary energy use of the buildings. We find that the passive house requirement strongly reduces the final energy use for heating compared to the current Swedish building code. However, the primary energy use is largely determined by the energy supply system, which is generally outside the mandate of the building standards. Overall, buildings with district heating have lower life-cycle primary energy use than alternatives heated with heat pump. The primary energy for production is small relative to that for operation, but it is more significant as the energy-efficiency standard of building improves and when efficient energy supply is used. Our results show the importance of a system-wide lifecycle perspective in reducing primary energy use in the built environment. A life cycle primary energy perspective is needed to minimize overall primary energy use, and future building energy-efficiency standards may reflect the full energy use during a building's life cycle. This could include primary energy implications for production, operation and end-of-life of buildings.

  • 9.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Energy use and overheating risk of Swedish multi-storey residential buildings under different climate scenarios2016In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 97, p. 534-548Article in journal (Refereed)
    Abstract [en]

    In this study, the extent to which different climate scenarios influence overheating risk, energy use and peak loads for space conditioning of district heated multi-storey buildings in Sweden are explored. Furthermore, the effectiveness of different overheating control measures and the implications of different electricity supply options for space cooling and ventilation are investigated. The analysis is based on buildings with different architectural and energy efficiency configurations including a prefab concrete-frame, a massive timber-frame and a light timber-frame building. Thermal performance of the buildings under low and high Representative Concentration Pathway climate scenarios for 2050–2059 and 2090–2099 are analysed and compared to that under historical climate of 1961–1990 and recent climate of 1996–2005. The study is based on a bottom-up methodology and includes detailed hour-by-hour energy balance and systems analyses. The results show significant changes in the buildings’ thermal performance under the future climate scenarios, relative to the historical and recent climates. Heating demand decreased significantly while cooling demand and overheating risk increased considerably with the future climate scenarios, for all buildings. In contrast to the cooling demand, the relative changes in heating demand of the buildings under the future climate scenarios are somewhat similar. The changes in the space conditioning demands and overheating risk vary for the buildings. Overheating risk was found to be slightly higher for the massive-frame building and slightly lower for the light-frame building.

  • 10.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Bonakdar, Farshid
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effects of future climate change scenarios on overheating risk and primary energy use for Swedish residential buildings2014In: Energy Procedia: INTERNATIONAL CONFERENCE ON APPLIED ENERGY, ICAE2014 / [ed] Yan, J; Lee, DJ; Chou, SK; Desideri, U; Li, H, Elsevier, 2014, p. 1179-1182Conference paper (Refereed)
    Abstract [en]

    In this study we use dynamic computer simulation modelling to investigate the potential impact of future climate change scenarios on the risk of overheating and annual primary energy requirements for space heating and cooling of residential buildings in Växjö, Sweden. The buildings are designed to the energy efficiency level of conventional or passive house, and are assumed to be heated with district heating and cooled with mechanical cooling system. We compare different climate change scenarios to a baseline which represents the climate data of Växjö for 1996-2005. The climate change scenarios are based on projected temperature changes under the representative concentration pathways (RCP) 4.5 and 8.5 scenarios. The result shows that the risk of overheating increases under the climate change scenarios. Furthermore space heating demand is reduced and cooling demand is increased for the analyzed buildings, and the changes are proportionally more significant for the passive compared to the conventional building.

  • 11.
    Dodoo, Ambrose
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Tettey, Uniben Yao Ayikoe
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    On input parameters, methods and assumptions for energy balance and retrofit analyses for residential buildings2017In: Energy and Buildings, ISSN 0378-7788, E-ISSN 1872-6178, Vol. 137, p. 76-89Article in journal (Refereed)
    Abstract [en]

    In this study we explore key parameter values, methods and assumptions used for energy balance modelling of residential buildings in the Swedish context and analyse their effects on calculated energy balance of a typical multi-storey building from 1970s and on energy savings of energy efficiency retrofit measures. The parameters studied are related to microclimate, building envelope, occupancy behaviour, ventilation, and heat gains from electric appliances and persons. Our study shows that assumed indoor air temperature, internal heat gains and efficiency of ventilation heat recovery units have significant effect on the simulated energy performance of the studied building and energy efficiency measures. Of the considered microclimate parameter values and assumptions, the outdoor temperature, ground solar reflection and window shading have significant impact on the simulated space heating and cooling demands. On the contrary, the simulated energy performances are less affected by the variations in air pressure outside and the percentage of wind load that hits the building. We found that input data and assumptions used for energy balance calculations and energy saving analyses vary significantly in the Swedish context. These result in significantly different calculated final energy performance of buildings and energy efficiency measures. To inform accurate analysis of energy performance of building and energy saving measures, input parameters used in simulation models need to be appropriate.

  • 12.
    Einvall, Jessica
    et al.
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Albertazzi, Simone
    Bologna University, Italy.
    Hulteberg, Christian
    Catator AB.
    Malik, Azhar
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Basile, Francesco
    Bologna University, Italy.
    Larsson, Ann-Charlotte
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Brandin, Jan
    Catator AB.
    Sanati, Mehri
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    Investigation of reforming catalyst deactivation by exposure to fly ash from biomass gasification in laboratory scale2007In: Energy & Fuels, ISSN 0887-0624, E-ISSN 1520-5029, Vol. 21, no 5, p. 2481-2488Article in journal (Refereed)
    Abstract [en]

    Production of synthesis gas by catalytic reforming of product gas from biomass gasification can lead to catalyst deactivation by the exposure to ash compounds present in the flue gas. The impact of fly ash from biomass gasification on reforming catalysts was studied at the laboratory scale. The investigated catalyst was Pt/Rh based, and it was exposed to generated K2SO4 aerosol particles and to aerosol particles produced from the water-soluble part of biomass fly ash, originating from a commercial biomass combustion plant. The noble metal catalyst was also compared with a commercial Ni-based catalyst, exposed to aerosol particles of the same fashion. To investigate the deactivation by aerosol particles, a flow containing submicrometer-size selected aerosol particles was led through the catalyst bed. The particle size of the poison was measured prior to the catalytic reactor system. Fresh and aerosol particle exposed catalysts were characterized using BET surface area, XRPD (X-ray powder diffraction), and H2 chemisorption. The Pt/Rh catalyst was also investigated for activity in the steam methane reforming reaction. It was found that the method to deposit generated aerosol particles on reforming catalysts could be a useful procedure to investigate the impact of different compounds possibly present in the product gas from the gasifier, acting as potential catalyst poisons. The catalytic deactivation procedure by exposure to aerosol particles is somehow similar to what happens in a real plant, when a catalyst bed is located subsequent to a biomass gasifier or a combustion boiler. Using different environments (oxidizing, reducing, steam present, etc.) in the aerosol generation adds further flexibility to the suggested aerosol deactivation method. It is essential to investigate the deactivating effect at the laboratory scale before a full-scale plant is taken into operation to avoid operational problems.

  • 13.
    Gustavsson, Leif
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Truong, Nguyen Le
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effects of different bioenergy pathways on primary energy efficiency, climate mitigation and energy system integration2015In: The 10th Conference on Sustainable Development of Energy, Water and Environment Systems – SDEWES 2015. September 27- October 3, 2015, Dubrovnik, Croatia, 2015Conference paper (Refereed)
    Abstract [en]

    Woody biomass is an important renewable energy resource that can be used directly or indirectly in the electricity, heat and transport sectors. Different technologies and conversion pathways can be used to convert woody biomass to supply different types of energy services. The primary energy and climate implications of bioenergy systems depend on which conversion technologies and pathways are used to produce the energy services, as well as how the services would have been supplied without the bioenergy system. Here, we focus on bioenergy for transportation in the context of a total renewable-based energy system. We contrast two different pathways: (i) biomotor fuel production in stand-alone plants and (ii) bioelectricity production in standalone plants and district heating systems with CHP plants and heat storage capacity for electric and plug-in hybrid vehicles. We quantify the primary energy use and the instantaneous biogenic CO2 of the two alternatives, per km of driving distance. We consider both commercially available technologies and emerging technologies for biomass-based conversion systems. Furthermore, for the two alternatives we discuss potential benefits of integration between the electricity, heating and transport sectors, to enable a better use of infrastructure. The results show that primary energy use and instantaneous biogenic CO2 emission vary strongly between the alternatives. The primary energy efficiency is much higher and gives less instantaneous biogenic CO2 emission for electric and plug-in hybrid vehicles compared to vehicles using biomotor fuels. Furthermore, the potential integration benefits between the electricity, heating and transport sectors are much larger due to the integration potential of heat storage capacity in DHS and battery storage capacity in electric and plug-in hybrid vehicles, as well as an improved overall integration capacity between the sectors. This study suggests that use of biomass should be considered in the context of the overall energy system, and in relation to the development of energy conversion technologies and integration potential between different energy sectors, to find primary energy efficient alternatives giving climate benefits in both a short- and long-term perspective.

  • 14.
    Haus, Sylvia
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Climate impact of the sustainable use of forest biomass in energy and material system: a life cycle perspective2018Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    Human society releases greenhouse gas emissions to the atmosphere while providing housing, heat, mobility and industrial production. Man-made greenhouse gas emissions are the main causes of climate change, coming mainly from burning fossil fuels and land-use changes. Sustainably managed forests play an important role in climate change mitigation with the prospect of sustainably providing essential materials and services as part of a low-carbon economy, both through the substitution of fossil-intensive fuels and material and through their potential to capture and store carbon in the long-term perspective.

    The overall aim of this thesis was to develop a methodology under a life cycle perspective to assess the climate impact of the sustainable use of forest biomass in bioenergy and material systems. To perform this kind of analysis a methodological framework is needed to accurately compare the different biological and technological systems with the aim to minimize the net carbon dioxide emissions to the atmosphere and hence the climate impact. In such a comparison, the complete energy supply chains from natural resources to energy end-use services has to be considered and are defined as the system boundaries.

    The results show that increasing biomass production through more intensive forest management or the usage of more productive tree species combined with substitution of non-wood products and fuels can significantly reduce global warming. The biggest single factor causing radiative forcing reduction was using timber to produce wood material to replace energy-intensive construction materials such as concrete and steel. Another very significant factor was replacing fossil fuels with forest residues from forest thinning, harvest, wood processing, and post-use wood products. The fossil fuel that was replaced by forest biomass affected the reductions in greenhouse gas emissions, with carbon-intensive coal being most beneficial to replace. Over the long term, an active and sustainable management of forests, including their use as a source for wood products and bioenergy allows the greatest potential for reducing greenhouse gas emissions.

  • 15.
    Haus, Sylvia
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Sathre, Roger
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Climate mitigation comparison of woody biomass systems with the inclusion of land-use in the reference fossil system2014In: Biomass and Bioenergy, ISSN 0961-9534, E-ISSN 1873-2909, Vol. 65, p. 136-144Article in journal (Refereed)
    Abstract [en]

    While issues of land-use have been considered in many direct analyses of biomass systems, little attention has heretofore been paid to land-use in reference fossil systems. Here we address this limitation by comparing forest biomass systems to reference fossil systems with explicit consideration of land-use in both systems. We estimate and compare the time profiles of greenhouse gas (GHG) emission and cumulative radiative forcing (CRF) of woody biomass systems and reference fossil systems. A life cycle perspective is used that includes all significant elements of both systems, including GHG emissions along the full material and energy chains. We consider the growth dynamics of forests under different management regimes, as well as energy and material substitution effects of harvested biomass. We determine the annual net emissions of CO2, N2O and CH4 for each system over a 240-year period, and then calculate time profiles of cRF as a proxy measurement of climate change impact. The results show greatest potential for climate change mitigation when intensive forest management is applied in the woody biomass system. This methodological framework provides a tool to help determine optimal strategies for managing forests so as to minimize climate change impacts. The inclusion of land-use in the reference system improves the accuracy of quantitative projections of climate benefits of biomass-based systems. (c) 2014 Elsevier Ltd. All rights reserved.

  • 16.
    Haus, Sylvia
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Sathre, Roger
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Greenhouse Gas Emission Comparison of Woody Biomass Systems with the Inclusion of Land-use in the Reference Fossil System2013In: 21st European Biomass Conference & Exhibition, Copenhagen, June 3-7, 2013, ETA-Florence Renewable Energies, , 2013, p. 1794-1799Conference paper (Refereed)
    Abstract [en]

    While issues of land-use have been considered in many analyses of biomass systems, little attention has heretofore been paid to land-use in reference fossil systems. In this study we address this limitation by comparing forest biomass systems to reference fossil systems with explicit consideration of land-use in both systems. We estimate and compare the time profiles of greenhouse gas (GHG) emission and cumulative radiative forcing (CRF) of woody biomass systems and reference fossil systems. A life cycle perspective is used that includes all elements of both systems and all GHG emissions along the full material and energy chains. We consider the growth dynamics of forests under different management regimes, as well as energy and material substitution effects. We determine the annual net emissions of CO2, N2O and CH4 for each system over a 240-year period. We then calculate time profiles of CRF as a proxy for climate change impacts. The results show greatest CRF reduction when fertilized forest management is applied in the woody biomass system. The results show the relevance of including land use options in both the biomass and the fossil system to accurately determine the climate impacts and benefits of forest management and product use.

  • 17.
    Hemström, Kerstin
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Contractor Perceptions of Very Energy Efficient New Multi-Story Residential Buildings2014In: World Sustainable Building 2014 Barcelona Conference: Sustainable Buildings: Results ; Are We Moving as Quickly as We Should? It's Up to Us!, GBCe , 2014Conference paper (Refereed)
    Abstract [en]

    To facilitate design of policies and strategies which aim to promote a sustainable development of the built environment, a deeper understanding of factors influencing the decisions taken in construction projects is needed. This study investigates Swedish contractors’ perceptions of the new-build of very energy efficiency multi-storey residential buildings (e.g. passive houses). The results of interviews with twenty selected contracts managers disclose several perceived disadvantages and risks associated with such buildings which influence the interest to invest in high energy efficiency. These include several cost and market-related issues as well as issues relating to the performance of the buildings. Without market intervention it seems unlikely that very energy efficient multi-storey residential buildings will diffuse to any substantial degree within the Swedish construction industry.

  • 18.
    Hemström, Kerstin
    et al.
    Mittuniversitetet.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Swedish private forest owners’ perceptions and intentions with respect to adopting exotic tree species2013In: European Journal of Forest Research, ISSN 1612-4669, E-ISSN 1612-4677, Vol. 132, no 3, p. 433-444Article in journal (Refereed)
    Abstract [en]

    Swedish forest growth can be increased through intensive forestry practices, enabling an increased use of forest biomass for climate-change mitigation. However, the diffusion of such practices depends on the forest owners’ adoption of them. We study Swedish private forest owners’ perceptions and intentions with respect to increasing forest growth by adopting exotic tree species. The results of a mail-in questionnaire survey show that although a majority of forest owners desire increasing forest growth, most owners have only a basic understanding of exotic tree species and a smaller proportion is interested in adopting them. The intention to adopt exotics seems to depend on the perceived performance of the species with respect to the economic aspects of forest management rather than on environmental or recreational concerns. Whereas a knowledge gap among the private forest owners regarding how to increase forest growth is implied, forest owners with higher self-rated knowledge of forestry and exotics have stronger intentions to adopt such species.

  • 19.
    Hjort, Åke
    et al.
    Euronom AB.
    Carlsson, Bo
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Method and Device for heating a building using a solar collector2014Patent (Other (popular science, discussion, etc.))
    Abstract [en]

    Method when heating a building with solar collectors comprising also a heat pump and energy storage using phase change materials. The invention is charaterized in that the energy storage system comprises to two containers, one placed indoors, where the phase change material has a melting point between 19 and 30 degrees Celsius, and a second container located outdoors and buried in the ground, where the phase change material has a conversion temperature which corresponds to or is lower  than the mean temperature of the ground surrounding the container.

  • 20.
    Joelsson, Jonas
    et al.
    Mittuniversitetet.
    Gustavsson, Leif
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Reductions in greenhouse gas emissions and oil use by DME (di-methyl ether) and FT Fischer-Tropsch) diesel production in chemical pulp mills2012In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 39, no 1, p. 363-374Article in journal (Refereed)
    Abstract [en]

    Using energy systems analysis, we examine the potential to reduce CO2 emissions and oil use by integrating motor biofuel production with pulp mills. BLG-DME (black liquor gasification with di-methyl ether production) is compared with solid biomass gasification with BIG-Fr (solid biomass gasification with Fischer-Tropsch fuel production). The studied systems are expanded with stand-alone production of biomass-based electricity and motor fuel so that they yield the same functional unit in terms of motor fuel and electricity as well as pulp or paper product, in order to facilitate comparison. More motor biofuel can be produced in integration with the studied mills with BLG-DME than with BIG-FT because the black liquor flow is large compared with other fuel streams in the mill and the integration potential for BIG-FT is limited by the mill's heat demand. When both systems are required to produce the same functional unit, the BLG-DME system achieves higher system efficiency and larger reductions in CO2 emissions and oil use per unit of biomass consumed. In general, integration of motor biofuel production with a pulp mill is more efficient than stand-alone motor biofuel production. Larger reductions in CO2 emissions or oil use can, however, be achieved if biomass replaces coal or oil in stationary applications.

  • 21.
    Joelsson, Jonas
    et al.
    Mittuniversitetet.
    Gustavsson, Leif
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Swedish biomass strategies to reduce CO2 emission and oil use in an EU context2012In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 43, no 1, p. 448-468Article in journal (Refereed)
    Abstract [en]

    Swedish energy strategies for transportation, space heating and pulp industries were evaluated with a focus on bioenergy use. The aims were to 1) study trade-offs between reductions in CO2 emission and oil use and between Swedish reductions and EU reductions, 2) compare the potential contributions of individual reduction measures, 3) quantify the total CO2 emission and oil use reduction potentials. Swedish energy efficiency measures reduced EU CO2 emission by 45-59 Mt CO2/a, at current biomass use and constant oil use. Doubling Swedish bioenergy use yielded an additional 40 Mt CO2/a reduction. Oil use could be reduced, but 36-81 kt of reductions in CO2 emission would be lost per Pi of oil use reduction. Swedish fossil fuel use within the studied sectors could be nearly eliminated. The expansion of district heating and cogeneration of heat with a high electricity yield were important measures. Plug-in hybrid electric cars reduced CO2 emission compared with conventional cars, and the difference was larger with increasing oil scarcity. The introduction of black liquor gasification in pulp mills also gave large CO2 emission reduction. Motor fuel from biomass was found to be a feasible option when coal is the marginal fuel for fossil motor fuel production. (C) 2012 Elsevier Ltd. All rights reserved.

  • 22.
    Johansson, Kristian
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustafsson, Filip
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Analys av förluster i småskaligt fjärrvärmenät: En studie för Lessebo Fjärrvärme2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [sv]

    Denna studie analyserar de rapporterat höga förlusterna i ett småskaligt fjärrvärmenät i Lessebo där styrkort för år 2013 redovisar förluster på 38 %. Genom att med en kvantitativ metod beräkna de värmeförluster som sker genom värmeledning i rörnätet görs en bedömning om rörnätets utformning är källan till de höga förlusterna eller ej. Studien ger indikationer på att fjärrvärmenätet i Lessebo är bra utformat och det därför finns oidentifierade orsaker till de höga förlusterna. Utöver redogörande av värmeförluster ger rapporten även kunskaper om fjärrvärmebranschens flera tekniker, begränsningar och framtida utvecklingsmöjligheter.

  • 23.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Morgalla, Mario
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Study on char fragmentation during biomass gasification in bubbling fluidized bed2015In: 23rd European Biomass Conference and Exhibition, 1-4 June 2015, Vienna, Austria, ETA-Florence Renewable Energies , 2015, p. 652-655Conference paper (Refereed)
    Abstract [en]

    In this work a bench scale bubbling fluidized bed gasifier was built to work with an aerosol sampling and measuring system in order to study char fragmentation phenomenon during biomass gasification process. Both barbeque char and wood pellets were gasified in CO2 (20 vol.%) -N2 mixture and steam (30 vol.%)-N2 mixture, respectively. An aerodynamic particle sizer (APS) was used to measure fragmented char particles during the whole gasification process. For the wood pellet gasification case, major fragmentation was observed during the devolatilization stage, which should be attributed to the combined effect of primary fragmentation and attrition. The aerodynamic diameter of those elutriable particles which can be measured by the current system was in the range of 0.5-8 µm. During the char gasification stage, a distinct mode of char fragments was produced in the size range of 1-7 µm in either case. The total mass concentration of elutriable particles gradually increased when gasification of char started, and then decreased while the reaction approached completion.

  • 24.
    Lin, Leteng
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Further development and application of aerosol-based method for on-line investigation of char reactivity in steam2013In: Proceedings for 21st European Biomass Conference and Exhibition, ETA-Florence Renewable Energies , 2013, p. 875-878Conference paper (Refereed)
    Abstract [en]

    Wood char was prepared from wood pellets under controlled pyrolysis conditions. The gasification kinetics for wood char in 33 vol% steam was established in the temperature range from 800ºC to 1300ºC by the combination of thermogravimetric analysis (TGA) and a novel aerosol-based method. The aerosol method was further developed and demonstrated successfully for generating, transporting and gasifying the suspended char particles (0.5-10 µm) in the steam atmosphere at high temperature up to 1300ºC. A tapered element oscillating microbalance (TEOM) was used to measure the change of mass concentrations of particles in the carrier gas, before and after gasification. The activation energy was 155 kJ·mol-1 for wood char with the pre-exponential factor of 3.56×104. This method can be potentially applied to on-line measure the reactivity of char particles directly in hot gas from the gasifier.

  • 25.
    Lindberg, Marcus
    et al.
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Johansson, Per
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Joélius, Mikael
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    LNG - Framtidens fartygsbränsle: Vad är det som hämmar utvecklingen av LNG-drift i Sverige?2015Independent thesis Advanced level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Shipping today faces stricter environmental requirements for pollution from vessels. Shipping companies have started to look for alternative fuel to achieve better environmental outcome. The Baltic Sea today is a major trading area for shipping . On 1 of January 2015 a new set of brand new and stricter regulation is getting implemented and these regulations are called SECA. Vessel running on LNG as an alternative fuel is today discussed extensively within the Swedish Maritime forum where emissions of NOx, sulfur and particles are less recipients than in heavy fuel oil (HFO). One of todays problems with a LNG distribution in Sweden are that the infrastructure is incomplete and outdated. This report has been built upon qualitative interviews with important actors within the Swedish maritime forum and also what impedes the development of the LNG’s infrastructure. The outcome of the interviews showed that the development has been slowed down because none within the Swedish martime forum have dared to take the first step. The ports does not want to develop terminals when there is no market demand and the shipping companies does not want to build vessel that runs on LNG when there is no market for distribution. Swedish governments involvement has been very weak, almost non-existing. There are also gaps in the Swedish regulations and restrictions of LNG cargo handling. This is aslo one of the factors that the development of LNG has been impeded. 

  • 26.
    Mainali, Brijesh
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. KTH Royal Institute of Technology.
    Ahmed, Hassan
    KTH Royal Institute of Technology.
    Silveira, Semida
    KTH Royal Institute of Technology.
    Integrated approach for provision of clean energy and water in rural Bangladesh2018In: Ground Water for Sustainable Development, ISSN 2352-801X, Vol. 7, p. 239-249Article in journal (Refereed)
    Abstract [en]

    The ultimate goal of this paper is to explore ways to upgrade energy and water services in rural areas of Bangladesh while improving resource recovery. The study analyzes the potential of a poly-generation system using locally available biomass resources (cow dung and agriculture residue) for providing cooking energy, electricity, and drinking water to a rural community. A questionnaire survey was conducted in Pani Para village with 52 households to investigate demand patterns and estimate the resource potential and amount of biogasneeded in the poly-generation system. A poly-generation system with 150 m3biogas digester and a 10 kWe generator is required to meet cooking energy, electricity and water demand in the village. Co-digestion of available resources including cow dung and agriculture residues can provide 48,250 m3 biogas/year, which is sufficient to supply electricity and clean drinking water to all households in the village. In addition, around two thirds of the households can use biogas for cooking. The sensitivity analysis shows that if the amount of agriculture residues is increased by 15%, also cooking gas can be provided to all households. The results indicate that such integrated solutions are worth further exploration.

  • 27.
    Mainali, Brijesh
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology. KTH Royal Institute of Technology.
    Luukkanen, Jyrki
    University of Turku, Finland.
    Silveira, Semida
    KTH-Royal Institute of Technology.
    Kaivo-oja, Jari
    University of Turku, Finland.
    Evaluating Synergies and Trade-Offs among Sustainable Development Goals (SDGs): Explorative Analyses of Development Paths in South Asia and Sub-Saharan Africa2018In: Sustainability, ISSN 2071-1050, E-ISSN 2071-1050, Vol. 10, no 3, article id 815Article in journal (Refereed)
    Abstract [en]

    Understanding the linkages between multiple targets of Sustainable Development Goals(SDGs) may help to integrate different sectoral programmes and develop coherent cross-sectoralpolicy to explore synergies. Synergy is interaction among two or more actions, which will lead toan impact greater or less than the sum of individual effects. Therefore, synergy can be positive ornegative (trade-off). This paper aims at developing an analytical framework to evaluate sectorallinkages and examine potential synergies and trade-offs among various SDGs’ goals and targets.Synergies and trade-offs related to energy access (SDG7), clean water and sanitation access (SDG6),food security and sustainable agriculture (SDG2) and poverty alleviation (SDG1) have been evaluatedfrom the perspective of developing countries using examples from South Asia (Bangladesh, Nepal,and Sri Lanka) and Sub-Saharan Africa (Ghana, Ethiopia and Rwanda), and historical data for theperiod between 1990 and 2012. The analytical framework includes both qualitative and quantitativemethods. Network analysis technique has been used for exploring the conceptual linkage amongdifferent indicators, and capturing the targets associated with SDGs. Advanced SustainabilityAnalysis (ASA) developed under the European framework programme has been used for quantifyingthe synergies and trade-offs among sustainability indicators. The analysis showed strong synergyamong various SDG targets. Interestingly, the potential synergy differs from country to countryand over time. Ghana and Sri Lanka had relatively higher potential synergy, whereas Rwanda andNepal had relatively lower potential synergy among the various targets. Higher synergy valueswere evidenced in those cases where the policy have recognized and emphasized on linkages amongcross-sectoral targets.

  • 28.
    Mainali, Brijesh
    et al.
    Linnaeus University.
    Mahapatra, Krushna
    Linnaeus University.
    Pardalis, Georgios
    Linnaeus University.
    Evaluating market models for deep-energy renovation using SWOT and PEST Analysis2018Conference paper (Other academic)
    Abstract [en]

    Buildings are responsible for 40% of energy consumption and 36% of CO2 emissions in the EU. Sweden and Denmark are cold climatic countries with strong demand for space heating and hot water in the residential sector. Large section of the detached houses in these countries are built more than 30 years ago and need refurbishment. Despite of huge energy saving potentials with deep renovation of these houses, there exists several challenges in realizing those saving potential. This paper evaluates the market for deep renovation of single-family houses in these two Nordic countries using PEST and SWOT analysis. Comparative analysis between two countries will help to understand the common and country specific drivers and barriers and to develop strategic recommendation in accordance.

  • 29.
    Mainali, Brijesh
    et al.
    KTH, Energi och klimatstudier, ECS.
    Pachauri, Shonali
    Rao, Narasimha
    Silveira, Semida
    KTH, Energi och klimatstudier, ECS.
    Assessing rural energy sustainability in developing countries2014In: Energy for Sustainable Development, ISSN 0973-0826, Vol. 19, no 1, p. 15-28Article in journal (Refereed)
    Abstract [en]

    Providing sustainable energy access is one of the most critical global challenges. This paper introduces a method for evaluating the status and progress of rural household energy sustainability in developing countries using a new composite indicator, the energy sustainability index (ESI). The ESI combines 13 techno-economic, environmental and social indicators of sustainability using principal component analysis (PCA). We apply the ES! to China, India, South Africa, Sri-Lanka, Bangladesh and Ghana between 1990 and 2010. The analysis suggests that South Africa's rural energy sustainability index is highest followed by China, Sri Lanka, India, Bangladesh and Ghana respectively. All the countries' rural energy sustainability has improved relatively over time except Ghana's. Improvements result mainly from increasing rural electricity use and increasing access to clean and efficient cooking fuels.

  • 30.
    Mainali, Brijesh
    et al.
    KTH, Energi och klimatstudier, ECS.
    Silveira, Semida
    KTH, Energi och klimatstudier, ECS.
    Alternative pathways for providing access to electricity in developing countries2013In: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 57, p. 299-310Article in journal (Refereed)
    Abstract [en]

    The discussion on electrification pathways tends to dangle between the merits of centralized on-grid versus decentralized off-grid electrification, and most of the time, both routes are promoted in parallel. However, the basis for choosing pathways has neither been very clear nor rational. This study compares three pathways for rural electrification considering (i) off-grid renewable energy (RE) technologies for individual households (ii) mini grids (with micro hydro and diesel generators) and (iii) grid extension. Different technological pathways are analyzed considering various technical and socio-economic parameters in two country cases: Nepal and Afghanistan. Levelized cost of electricity (LCOE) is taken as the main basis for comparison of the various options, in which both environmental externalities and life cycle costs are considered. The analysis shows that the micro hydro based mini grid technology is the most competitive alternative for electrifying isolated and remote rural areas in both countries. Individual household technology should be promoted only in places with scattered households where there is no possibility of mini grid solution. The choice of technology and the pathway adopted in Nepal seems functional, though some flaws within the pathways need to be addressed. In Afghanistan, the technological pathways for rural electrification are not well-defined and the country lacks a clear cut national policy framework for rural electrification. Here, micro hydro based mini grid would be a more sustainable proposition rather than diesel generators as promoted in the transitional phase. Afghanistan can benefit from lessons learnt in Nepal not least in the formation of markets for renewable technologies.

  • 31.
    Mainali, Brijesh
    et al.
    KTH, Energi och klimatstudier, ECS.
    Silveira, Semida
    KTH, Energi och klimatstudier, ECS.
    Using a sustainability index to assess energy technologies for rural electrification2015In: Renewable & sustainable energy reviews, ISSN 1364-0321, E-ISSN 1879-0690, Vol. 41, p. 1351-1365Article in journal (Refereed)
    Abstract [en]

    This paper introduces a method for evaluating the sustainability performance of energy technologies applied in rural electrification, using the multivariate technique called Principal component analysis (PCA).The sustainability is assessed in terms of energy technology sustainability index (ETSI). The ETSI has been used for assessing the sustainability performance of ten different energy systems in the case of India. Since this method is static in nature, the sustainability performance analysis is made for three different years (2005, 2010 and 2015) to capture technological advancements and changes in market conditions for the various technologies over time. The result shows that mature technologies such as biomass gasifiers, biogas and microhydro technologies have relatively better sustainability performance among the options analyzed. There is slight increment in their sustainability performance in the ten year period considered. Emerging technologies such as solar and wind have fairly good improvement in the sustainability performance over the studied time but still have difficulties competing with the mature technologies and conventional technologies without policy support. Analysis has been made with probable, minimum and maximum capital costs, operational and fuel costs to capture uncertainty among the input assumptions, and sensitivity has been reflected in the analysis of energy technology sustainability index (ETSI). This ETSI could help improve energy technology assessments, particularly when it comes to the feasibility of available alternatives.

  • 32.
    Morgalla, Mario
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Lin, Leteng
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Characterization Of Particulate Matter In Biomass Gasification2015In: Proceedings for the 23rd European Biomass Conference and Exhibition / [ed] I. Obernberger, D. Baxter, A.Grassi, P.Helm, ETA-Florence Renewable Energies , 2015, p. 664-667Conference paper (Refereed)
    Abstract [en]

    The purpose of this work is to examine the potential of monitoring heavy tar compounds contained in the product gas of a biomass gasifier. The hot product gas from atmospheric indirect bubbling fluidized bed gasification of wood pellets was extracted. The sampling and conditioning system consisted of a high-temperature dilution probe, a primary thermodenuder and a secondary thermodenuder. Online and semi-online instruments were used to characterize the aerosol in terms of number size distribution and particle mass concentration. The fine mode (mobility equivalent diameter db < 150 nm) was found to mainly consist of heavy tar compounds. An Electrical low­pressure impactor (ELPI) was used to measure this mode with a time resolution of 1 second and thus showed the potential for online measurements of heavy tar.

  • 33.
    Munkacsi, Noemi
    et al.
    Budapest University of Technology and Economics, Hungary.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    The role of social influence in the end customer purchasing decisions on the heat market2017In: Proceedings from eceee Summer Studies, European Council for an Energy Efficient Economy (ECEEE), 2017Conference paper (Refereed)
    Abstract [en]

    The aim of this paper is to examine the role of social influence on the end customer behaviour in the purchase of heating products in residential segment. The study is based on interviews and questionnaire survey of homeowners in Hungary in 2013. Respondents are open to learn about diverse innovative heating technologies, energy types and diverse heating fuels irrespective of any purchase intention. They plan their purchase based on deliberate considerations rather than facing an emergency heating appliance breakdown. Furthermore, influence of the social environment prevails at the diverse stages of the purchase process. End customers actively conduct social search (family, friends, neighbours, colleagues, other customers with purchase experience over the Internet, etc.) besides the influencing role of the installer.

  • 34.
    Nilsson, Bengt
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nilsson, Daniel
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Distribution of logging residues at the clear-felled site after fuel adapted logging operations2015In: Papers of the 23rd European Biomass Conference: Setting the course for a biobased economyExtracted from the Proceedings of the International Conference held in Viennna, Asutria1-4 June 2015 / [ed] Obernberger I, Baxter D, Grassi A, Helm P, ETA-Florence Renewable Energies , 2015, p. 270-272Conference paper (Refereed)
    Abstract [en]

    During extraction of logging residues previous studies in Sweden have shown that up to 50% of the available logging residues will not reach the energy-conversion site. The remaining potential of the logging residues are therefore lost by handling either at the clear-felled site, during transportation or due to decomposition. An outtake of 100% is not possible or desired, since the Swedish Forest Agency recommends that at least 20% of the logging residues should be left at the clear-felled site after a fuel adapted logging operation. In this study the losses at the clear-felled area is examined by studying the distribution of the remaining logging residues under and between the harvester heaps as well amount of logging residues that are left at the roadside landing after comminution. The results show that most of the reaming logging residues are well distributed at the clear-felled area between the harvester heaps. Additional logging residues are left at the clear-felled area since the forwarder cannot gather all logging residues from under the harvester heaps. In addition to this a not insignificant amount of logging residues are left at the roadside landing.

  • 35.
    Nilsson, Bengt
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nilsson, Daniel
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Distributions and Losses of Logging Residues at Clear-Felled Areas during Extraction for Bioenergy: Comparing Dried- and Fresh-Stacked Method2015In: Forests, ISSN 1999-4907, E-ISSN 1999-4907, Vol. 6, no 11, p. 4212-4227Article in journal (Refereed)
    Abstract [en]

    It is well known that a large proportion of available logging residues intended for extraction will not reach the energy-conversion industry, because some are lost during transportation or left on the clear-felled area. However, there is little understanding of where logging residue losses occur in the supply chain. In this study, the distribution of logging residues for two methods (dried- and fresh-stacked method) to extract logging residues were studied in one clear-felled area. In addition, residue fractions were examined in a detailed comparison. Even though the fresh-stacked method left somewhat more logging residues at the clear-felled area, the differences are small between the methods. Approximately 30% of the total amount of logging residues was left behind between the harvester heaps, with an additional 10%-15% under these heaps and approximately 2%-3% beneath the windrows. The final product that was delivered to the energy-conversion industry was very similar, regardless of the extraction method used. The delivered chipped logging residues had moisture contents of 37% and 36% following fresh- and dried-stacked methods respectively, and in both cases the needle content in the processed logging residues was approximately 10%. However, the total amount of fine fractions (needles and fines) was slightly higher following dried-stacking.

  • 36.
    Nilsson, Daniel
    et al.
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nilsson, Bengt
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Thörnqvist, Thomas
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Nutrient removal after whole-tree harvesting with the traditional Swedish dried-stacked method for removal of logging residues2015In: Papers of the 23rd European Biomass Conference: Setting the course for a biobased economyExtracted from the Proceedings of the International Conference held in Viennna, Asutria1-4 June 2015 / [ed] Obernberger I, Baxter D, Grassi A, Helm P, ETA-Florence Renewable Energies , 2015, p. 9-13Conference paper (Refereed)
    Abstract [en]

    Bioenergy from logging residues is an important contributor to Swedish energy supplies. Logging residues where long defined and regarded as the unmerchantable aboveground biomass left behind in the clear-felled area, consisting of branches, tops and small trees that are gathered after the round wood harvest, but logging residues are nowadays regarded as a third assortment next to timber and pulpwood with high economic value. However long-term experiments on removal of logging residues from Norway spruce (Picea abies (L.)Karst) stands have shown both growth reductions and growth increase in the next generation, because of decreasing amounts of nutrients. So an increased removal of logging residues requires some sort of compensation of nutrients. Therefore it is of importance to investigate how much nutrients that is removed from the stand after whole-tree harvesting.

    In this study the removal of the nutrients nitrogen (N), phosphorus (P), calcium (Ca), potassium (K) and magnesium (Mg) have been investigated by laboratory analysis of the nutrients together with the actual removal of stemwood, bark and logging residues. The study has also investigated the distribution of nutrients at the clear-felled area.

    The results show that approximately half of the total nutrient removed in whole tree harvesting is done with the removal of stemwood and bark. The results also show that approximately 30% of the total amount of nutrients is left at the clear-felled area.

  • 37.
    Pardalis, Georgios
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mainali, Brijesh
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Organizational preparedness to adopt one-stop-shop concept: A study on house renovation stakeholders in Sweden2018In: Conference on ADVANCED BUILDING SKINS 2018, Bern, Switzerland, 28-29 October, 2018, Bern, Switzerland, 2018Conference paper (Refereed)
    Abstract [en]

    This study examines the views of stakeholders involved in house renovations regarding the one-stop-shop business concept innovation, and assesses their level of preparedness to adopt such a concept in order to enter the promising market of detached house renovations. The investigation is based on 25 interviews with construction SMEs owners, real estate agents and loan consultants, and on a conceptual framework for organizational innovation adoption. The results suggest that for the nonce, none of the examined stakeholders is likely to adopt a one-stop-shop business model to enter the market of detached house renovations, even though this concept is seen as one with great potential. This mostly happens due to their individual characteristics, the complexity of one-stop-shop model related to their way of doing business and the uncertainties deriving from the adoption of such a model. Furthermore, the participation of an entrepreneur is proposed, who would coordinate all the different actors involved in the renovation process, and whose role can be further examined.

  • 38.
    Pardalis, Georgios
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mainali, Brijesh
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Mahapatra, Krushna
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Organizational preparedness to adopt one-stop-shop concept: A study on house renovation stakeholders in Sweden2018In: Conference on ADVANCED BUILDING SKINS 2018, Bern, Switzerland, 28-29 October, 2018, Bern, Switzerland, 2018Conference paper (Refereed)
    Abstract [en]

    This study examines the views of stakeholders involved in house renovations regarding the one-stop-shop business concept innovation, and assesses their level of preparedness to adopt such a concept in order to enter the promising market of detached house renovations. The investigation is based on 25 interviews with construction SMEs owners, real estate agents and loan consultants, and on a conceptual framework for organizational innovation adoption. The results suggest that for the nonce, none of the examined stakeholders is likely to adopt a one-stop-shop business model to enter the market of detached house renovations, even though this concept is seen as one with great potential. This mostly happens due to their individual characteristics, the complexity of one-stop-shop model related to their way of doing business and the uncertainties deriving from the adoption of such a model. Furthermore, the participation of an entrepreneur is proposed, who would coordinate all the different actors involved in the renovation process, and whose role can be further examined.

  • 39.
    Paulrud, Susanne
    et al.
    Research Institutes of Sweden (RISE).
    Gustavsson, Lennart
    Research Institutes of Sweden (RISE).
    Johansson, Jimmy
    Linnaeus University, Faculty of Technology, Department of Forestry and Wood Technology.
    Tekniska och ekonomiska förutsättningar för oljeersättning i industrin med pyrolysolja2017Other (Other academic)
  • 40.
    Persson, Helena
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Carlsson, Bo
    Linnaeus University, Faculty of Health and Life Sciences, Department of Biology and Environmental Science.
    Perers, Bengt
    DTU.
    Development and validation of a TRNSYS/TRNSED-software for combi-heating systems2013Manuscript (preprint) (Other academic)
    Abstract [en]

    There is a need for accurate and readily available information about theoptimization, economics, and environmental impacts of combi-heating systems.Accordingly, the authors have developed TRNSYS-based software called Flexifuel thatincludes a TRNSED application for calculating the annual system performance ofcombi-heating systems involving any combination of heat pumps, flat or vacuumtube solar collectors, pellet burners, electric auxiliary heaters, and heatstorage tanks. Selection of less complex software systems and types reduces thesimulation time without significantly affecting the accuracy of the results.Annual performance data for a system can be simulated in from one to twominutes. Comparison of accumulated theoretical and measured performance dataover the time period for a full-scale test plant with heat pumps and solarcollectors showed that simulation errors were below 5%.

  • 41.
    Persson, Helena
    et al.
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Perers, Bengt
    DTU.
    Carlsson, Bo
    Linnaeus University, Faculty of Science and Engineering, School of Natural Sciences.
    Type12 and Type56: a load structure comparison in TRNSYS2011Conference paper (Refereed)
  • 42.
    Poudel, Bishnu Chandra
    et al.
    Mid Sweden University.
    Sathre, Roger
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Bergh, Johan
    SLU, Alnarp.
    Gustavsson, Leif
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Lundström, Anders
    Hyvonen, Ritta
    Potential effects of intensive forestry on biomass production and total carbon balance in north-central Sweden2012In: Environmental Science and Policy, ISSN 1462-9011, E-ISSN 1873-6416, Vol. 15, no 1, p. 106-124Article in journal (Refereed)
    Abstract [en]

    We quantify the potential effects of intensive forest management activities on forest production in north-central Sweden over the next 100 years, and calculate the potential climate change mitigation feedback effect due to the resulting increased carbon stock and increased use of forest products. We analyze and compare four different forest management scenarios (Reference, Environment, Production, and Maximum), all of which include the expected effects of climate change based on SRES B2 scenario. Forest management practices are intensified in Production scenario, and further intensified in Maximum scenario. Four different models, BIOMASS, HUGIN, Q-model, and Substitution model, were used to quantify net primary production, forest production and harvest potential, soil carbon, and biomass substitution of fossil fuels and non-wood materials, respectively. After integrating the models, our results show that intensive forestry may increase forest production by up to 26% and annual harvest by up to 19%, compared to the Reference scenario. The greatest single effect on the carbon balance is from using increased biomass production to substitute for fossil fuels and energy intensive materials. Carbon stocks in living tree biomass, forest soil and wood products also increase. In total, a net carbon emission reduction of up to 132 Tg (for Maximum scenario) is possible during the next 100 years due to intensive forest management in two Swedish counties, Jamtland and Vasternorrland

  • 43.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Hermansson, Sven
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Characterization of the fuel bed combustion of wood residues in a 4 MW grate boiler2015In: European Biomass Conference and Exhibition Proceedings, 2015, p. 741-744Conference paper (Refereed)
    Abstract [en]

    Information about distributions of temperature and gas species within the fuel bed is of great importance in studying the formation of pollutants in an industrial-scale biomass boiler. The main objective of this study was to investigate the gas composition and temperature in some available sections of the fuel bed of a 4 MW reciprocating grate boiler, burning mixture of fresh pine wood chips, bark, and sawdust with two significantly different moisture content levels. The averageCO, CO2,CH4, and O2 concentrations measured during the combustion of the more moist fuel (about 60 mass %) were about 12, 12, 2, and 4 vol. %, respectively, whereas the corresponding values for the less moist fuel (about 45 mass %) were about15, 10, 2.5, and 5 vol. %, respectively. Higher concentration of CO and lower concentration of CO2 for the less moist fuel could originate either from the char conversion process or from the reactions of the devolatilizationgas products.

  • 44.
    Razmjoo, Narges
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Strand, Michael
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    In-bed combustion charachteristics of wet wood chips and sawdust in a full-scale grate boiler2017In: Proceedings 13th International Conference on Energy for a Clean Environment, 2017Conference paper (Refereed)
  • 45.
    Rehnström, Johan
    et al.
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Isak, Undestam
    Linnaeus University, Faculty of Technology, Kalmar Maritime Academy.
    Effektivisering av kylmedelskylare på Nybro Energis kraftvärmeverk.: Bibehållen kyleffekt även vid höga omgivningstemperaturer för full effekt på pannan utan att överstrida befintlig ljudnivå. Minskning av elförbrukning.2018Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Waste-cogeneration plants are paid today to receive and burn waste. These revenues are often higher than the revenues from electricity generation and heat production, so you want to burn as much as possible in most circumstances. In order to take advantage of the surplus effect that may occur, it eliminates what you do not need.

    Nybro Energi's CHP plant in Transtorp uses 6 cooling packs with 4 fans on each in order to cool off this excess power. During installation, the goal was to be able to cool off 10MW but it turned out that during summer when the outdoor temperature became higher, the cooling power could go down to 7MW.

    Our purpose of investigation was to use a new engine with a higher cos α to test on one of the fans and see if you can increase the cooling power and reduce the consumption of the engines without the cooling packages giving higher noise levels than before.

    An alternative to only reducing the current on the old motor is to phase compensate and according to calculations the motors current can be reduces from 8.2A to 3.88A.

    It was found that the new engine when frequency controlled at 40hz pulls higher active power but significantly less reactive power that makes it cheaper in operation. During the measurements to obtain the cooling effect, doubtful values ​​were measured which showed that it cooled worse at 40hz than the previous engine despite a higher fan speed. This is not correct theoretically and it is unreasonable that it will not cool better but a figure exactly how much could not be produced. At 40hz, the new engine will also produce less noise if you choose to replace all 28 engines. This despite the fact that a fan is going to run more at a higher speed, it was found that the noise from the engine itself is lower in the new engine. If you go up to 50hz frequency and expect 28 new engines, you'll get a sound boost of 5dB at 300m compared to the old engine. This can be lowered by 3dB if you manage to eliminate the properties of the adjacent wall sound reflectors. The new engine is recommended as it has many advantages and if you want to drive at higher frequencies, you can advantageously use sound absorbers along the wall to eliminate its double effect on the noise level.

  • 46.
    Sathre, Roger
    et al.
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Haus, Sylvia
    Linnaeus University, Faculty of Technology, Department of Building and Energy Technology.
    Time Dynamics and Radiative Forcing of Forest Bioenergy Systems2013In: Forest BioEnergy Production: Management, Carbon Sequestration and Adaptation, Springer, 2013, p. 185-206Chapter in book (Refereed)
    Abstract [en]

    In this chapter we explore the temporal dynamics of using forest bioenergy to mitigate climate change. We consider such issues as: growth dynamics of forests under different management regimes; the substitution effects of different bioenergy and biomaterial uses; temporary carbon storage in harvested biomass; the availability of different biomass fractions at different points of a wood product life cycle; and changes in carbon content of forest soils. We introduce the metric of radiative forcing, which quantifies the accumulating energy due to the global greenhouse effect, and we describe a method to estimate quantitatively and to compare the cumulative radiative forcing (CRF) of forest bioenergy systems and reference fossil energy systems. In three case studies, we describe the time dynamics and estimate the CRF profiles of various forest biomass systems.

  • 47.
    Sathre, Roger
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Truong, Nguyen Le
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Climate effects of electricity production fuelled by coal, forest slash and municipal solid waste with and without carbon capture2017In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 122, p. 711-723Article in journal (Refereed)
    Abstract [en]

    We analyse the climate implications of producing electricity in large-scale conversion plants using coal, forest slash and municipal solid waste with and without carbon capture and storage (CCS). We calculate the primary energy, carbon dioxide (CO2) and methane (CH4) emission profiles, and the cumulative radiative forcing (CRF) of different systems that produce the same amount of electricity. We find that using slash or waste for electricity production instead of coal somewhat increases the instantaneous CO2 emission from the power plant, but avoids significant subsequent emissions from decaying slash in forests or waste in landfills. For slash used instead of coal, we find robust near- and long-term reductions in total emissions and CRF. Climate effects of using waste instead of coal are more ambiguous: CRF is reduced when CCS is used, but without CCS there is little or no climate benefits of using waste directly for energy, assuming that landfill gas is recovered and used for electricity production. The application of CCS requires more fuel, but strongly reduces the CO2 emissions. The use of slash or waste together with CCS results in negative net emissions and CRF, i.e. global cooling.

  • 48.
    Tessema, Zereay
    et al.
    KTH, Energi och klimatstudier, ECS.
    Mainali, Brijesh
    KTH, Energi och klimatstudier, ECS.
    Silveira, Semida
    KTH, Energi och klimatstudier, ECS.
    Mainstreaming and sector-wide approaches to sustainable energy access in Ethiopia2014In: Energy Strategy Reviews, ISSN 2211-467X, E-ISSN 2211-4688, Vol. 2, no 3-4, p. 313-322Article in journal (Refereed)
    Abstract [en]

    Access to modern and sustainable energy services is a real challenge for countries where the majority of rural population is living in austere poverty. The importance of sustainable energy access is recognized in many developing countries, and there is growing international development assistance in the sector. However the achievements are still meager particularly in Sub Saharan African countries. Most countries often fail to prioritize sustainable energy services at the local level as a means to achieve economic growth at the national level as well as the Millennium Development Goals. This study is focused on Ethiopia and investigates the existing challenges and future prospects of mainstreaming sustainable energy access into the development planning process of the country, and the implications this may have for international donor agencies, national policy makers, private actors and local energy planners. The paper analyzes the institutional framework, sector policy and financial mechanisms in the country. It also discusses operational modalities of state and non-state actors in the process, and extracts policy recommendations.

  • 49.
    Truong, Nguyen Le
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Costs and primary energy use of energy supply options to buildings of different energy efficiency levels2016In: 2016 ACEEE Summer Study on Energy Efficiency in Buildings: From Components to Systems, From Buildings to Communities, American Council for an Energy Efficient Economy, 2016Conference paper (Refereed)
    Abstract [en]

    An appropriate energy solution for buildings depends on the scale of demand and the availability of the surrounding technical infrastructure. Building energy demand can be altered by the application of various energy efficiency measures whereas the performance of the energy supply system can be changed by the involvement of various technologies. As a result, optimal energy supply options could depend on various parameters that depend on specific contexts. In this study, different options to supply energy to apartment buildings of different energy efficiency levels in Sweden are investigated. Different renewable-based alternatives to produce heat and electricity based on various state-of-the-art technologies are considered. The optimizations are based on the hourly variation throughout the year of energy demand and of different energy supply systems that change with the ambient conditions such as temperature and solar radiation. The results prove that optimal options for a building depend on its scale of energy demand and on the availability of technologies in the market. Also, there is a tradeoff between monetary costs and primary energy use in supplying energy to apartment buildings. This study shows that it is essential to consider the interaction between energy demand and supply to estimate the costs and primary energy use for energy supply alternatives. A heating system with an electric heat pump shows to be primary energy efficient option whereas that with a wood pellet boiler is a more cost efficient once. However, an energy supply option based on a combined heat and power unit using fuel cell technology could potentially be the most cost- and primary energy efficient option for buildings with low energy demand.

  • 50.
    Truong, Nguyen Le
    et al.
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Dodoo, Ambrose
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Gustavsson, Leif
    Linnaeus University, Faculty of Technology, Department of Built Environment and Energy Technology.
    Effects of energy efficiency measures in district-heated buildings on energy supply2018In: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 142, p. 1114-1127Article in journal (Refereed)
    Abstract [en]

    In this study we estimate the final and primary energy savings for different energy efficiency measures in a multi-apartment building when heated by small-, medium- or large-scale district-heat production systems (DHSs). The small-scale system is based on heat-only boilers, whereas the other two also include cogeneration of district heat and electricity. In the systems with cogeneration units, a change in building's heat demand may influence cogenerated electricity and hence the overall power system. For the building analyzed, the estimated annual total final heat and electricity savings were 136 (54%) and 30 MWh (52%), respectively, giving total annual primary energy savings of 177–289 MWh. This varies as the ratio of primary and final heat savings depends on the type of energy efficiency measure and the energy supply. For the same heat savings measure, a system with a heat-only boiler gave the highest primary energy savings, whereas a system based mostly on cogeneration of district heat and electricity in combination with averaged-efficiency standalone power plants gave the lowest primary energy savings. When the energy supply is based on energy-efficient renewable-based system, the differences in primary energy savings between large- and small-scale DHSs are minor for the same energy efficiency measure.

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