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  • 101. Liu, Junguo
    et al.
    Mao, Ganquan
    Hoekstra, Arjen Y.
    Wang, Hao
    Wang, Jianhua
    Zheng, Chunmiao
    van Vliet, Michelle T. H.
    Wu, May
    Ruddell, Benjamin
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Managing the energy-water-food nexus for sustainable development2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 210, p. 377-381Article in journal (Other academic)
  • 102.
    Liu, Minzhang
    et al.
    Tianjin Univ, Sch Environm Sci & Engn, Tianjin 300072, Peoples R China..
    Zhu, Chunguang
    Tianjin Univ, Sch Environm Sci & Engn, Tianjin 300072, Peoples R China..
    Zhang, Huan
    Tianjin Univ, Sch Environm Sci & Engn, Tianjin 300072, Peoples R China.;Tianjin Univ, Minist Educ China, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    Zheng, Wandong
    Tianjin Univ, Sch Environm Sci & Engn, Tianjin 300072, Peoples R China.;Tianjin Univ, Minist Educ China, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    You, Shijun
    Tianjin Univ, Sch Environm Sci & Engn, Tianjin 300072, Peoples R China.;Tianjin Univ, Minist Educ China, Key Lab Efficient Utilizat Low & Medium Grade Ene, Tianjin 300350, Peoples R China..
    Campana, Pietro Elia
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    The environment and energy consumption of a subway tunnel by the influence of piston wind2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 246, p. 11-23Article in journal (Refereed)
    Abstract [en]

    With the flourishing development of the subway construction, it becomes increasingly urgent to improve the subway tunnel environment and reduce the energy consumption of the tunnel ventilation system. The tunnel environment is significantly affected by the piston wind, which is influenced by the train speed. In this paper, a three-dimensional computational model of a subway tunnel is developed and validated through experiments. The model is used to study the carbon dioxide concentration and thermal environment of the subway tunnel. The optimal train speed is proposed with the aim to minimize the volume of mechanical supply air and to optimize the carbon dioxide concentration and thermal environment of the tunnel. In parallel with the considerations of tunnel environment, the subways in 25 cities of China are analyzed to study the energy conservation of the tunnel ventilation system by making full use of piston wind. The results indicate that the optimal train speed is 30 m/s based on the carbon dioxide concentration and thermal environment. The effective utilization of the piston wind can reduce 13% similar to 32% of the energy consumption for tunnel ventilation. The calculation method of the optimal train speed developed in this paper is also applicable to ordinary railway tunnels and high-speed railway tunnels.

  • 103. Liu, Zhu
    et al.
    Feng, Kuishuang
    Davis, Steven J.
    Guan, Dabo
    Chen, Bin
    Hubacek, Klaus
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. Malardalen University (MDU), Sweden.
    Understanding the energy consumption and greenhouse gas emissions and the implication for achieving climate change mitigation targets2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 184, p. 737-741Article in journal (Other academic)
  • 104.
    Lorenzi, Guido
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Univ Lisbon, Inst Super Tecn.
    Santos Silva, Carlos Augusto
    Comparing demand response and battery storage to optimize self-consumption in PV systems2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 180, p. 524-535Article in journal (Refereed)
    Abstract [en]

    The paper examines and compares the potential of storage in batteries versus demand response strategies for electricity bill reduction in the residential sector, in the context of the new trend of installing PV systems for self-consumption. The performances of the two methodologies are investigated by applying them to the data of a real household which owns a small solar photovoltaic installation. The benefits of storage and demand response are evaluated through an optimization analysis with a linear programming algorithm. The simulations are carried out both for real market prices of the equipment and for reduced ones, to simulate the case of strong technological development and the corresponding price decrease in the coming years. The electricity pricing scheme is a dual tariff regime modeled according to the Portuguese current rules. The results suggest that at the moment, demand response should be preferred with the current market prices of the hardware. However, a significant decrease in the batteries price can make storage an interesting alternative, especially for the cases in which demand response is not easily applicable.

  • 105.
    Lv, Yuexia
    et al.
    Qilu Univ Technol, Shandong Acad Sci, Sch Mech & Automot Engn, Jinan, Shandong, Peoples R China.;Ningbo RK Solar Tech Ltd, Ningbo, Zhejiang, Peoples R China..
    Si, Pengfei
    Tsinghua Univ, Sch Architecture, Beijing, Peoples R China.;China Southwest Architecture Design & Res Inst Co, Chengdu, Sichuan, Peoples R China..
    Rong, Xiangyang
    China Southwest Architecture Design & Res Inst Co, Chengdu, Sichuan, Peoples R China..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes. Malardalen Univ, Sch Business Soc & Energy, Vasteras, Sweden..
    Feng, Ya
    China Southwest Architecture Design & Res Inst Co, Chengdu, Sichuan, Peoples R China..
    Zhu, Xiaohong
    Sichuan Prov Architectural Design Inst, Chengdu, Sichuan, Peoples R China..
    Determination of optimum tilt angle and orientation for solar collectors based on effective solar heat collection2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 219, p. 11-19Article in journal (Refereed)
    Abstract [en]

    Determination of optimum tilt angle and orientation of solar collectors by maximizing the total solar radiation may overestimate the energy production benefits, because a considerable amount of solar radiation is ineffective for practical solar collectors. In this paper, the concept of effective solar heat collection is proposed to rule out the ineffective solar radiation that could not be converted to available energy. Accordingly, an optimized mathematical model is developed and used to determine the optimum tilt angle and orientation of solar collectors installed in Lhasa during the heating season. Compared with the total solar radiation based optimum results, there is a deviation of 5 degrees in the optimum orientations based on the effective solar heat collection. The case study shows that it is not advisable to adjust the optimum tilt angle on a monthly basis because there is no significance change in total solar energy gains in comparison with the case of no such adjustment during the heating season. In addition, the correction factors to achieving the maximum effective solar heat collection are given at different tilt angles and orientations to guide installation of solar collectors in practical engineering applications.

  • 106. Lv, Yuexia
    et al.
    Yu, Xinhai
    Jia, Jingjing
    Tu, Shan-Tung
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Dahlquist, Erik
    Fabrication and characterization of superhydrophobic polypropylene hollow fiber membranes for carbon dioxide absorption2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1, p. 167-174Article in journal (Refereed)
    Abstract [en]

    The membrane wetting by amine absorbents results in performance deterioration of membrane gas absorption system for CO(2) post-combustion capture. To solve this problem, in this study, the polypropylene membrane fiber was modified by depositing a rough layer on the surface to improve its hydrophobicity. Weighing the coating homogeneity, hydrophobicity and modification process efficiency, the mixture of cyclohexanone and MEK system was considered as the best non-solvent. The contact angle increased dramatically from 122 to 158 by the modification, thereby obtaining superhydrophobic membrane surface. The membrane-absorbent interaction results demonstrated that the modification treatment effectively enhanced the stability and maintained the superhydrophobicity of fibers contacting with the absorbent. In addition, continuous CO(2) absorption experiments for up to 20 days were carried out in untreated and modified polypropylene hollow fiber membrane contactors, using 1 mol L(-1) MEA solution as the absorbent. The long-term system operation results indicated that, even though additional mass transfer resistance was introduced by the surface coating, the modified polypropylene hollow fiber membrane contactor was still technically feasible for CO(2) capture from the power stations.

  • 107. Lv, Yuexia
    et al.
    Yu, Xinhai
    Tu, Shan-Tung
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Dahlquist, Erik
    Experimental studies on simultaneous removal of CO2 and SO2 in a polypropylene hollow fiber membrane contactor2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, p. 283-288Article in journal (Refereed)
    Abstract [en]

    Membrane gas absorption technology is a promising alternative to conventional technologies for the mitigation of acid gases. In this study, simultaneous removal of SO2 and CO2 from coal-fired flue gas was carried out in a polypropylene hollow fiber membrane contactor using aqueous monoethanolamine as the absorbent. The influences of liquid and gas flow rates on the simultaneous absorption performance of CO2 and SO2 were investigated. The experimental results indicated that the membrane contactor could eliminate these two sour gases simultaneously and effectively. Absorption of SO2 and CO2 was enhanced by the increase in liquid flow rate and decrease in gas flow rate. It was observed that a small amount of SO2 in the flue gas had a slight influence on the absorption of CO2. In addition, the membrane contactor was operated continuously for two weeks to evaluate its duration performance. The results showed that the CO2 mass transfer rate was decreased significantly with the operating time due to partial wetting of membrane pores. After 14 days of continuous operation, the CO2 mass transfer rate of the wetted membrane contactor was decreased by 41% but could be retrieved to 86% of the fresh one by increasing the gas phase pressure.

  • 108. Lyngfelt, Anders
    et al.
    Epple, Bernd
    Adanez, Juan
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    The 3rd International Conference on Chemical Looping 20142015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 157, p. 285-287Article in journal (Other academic)
  • 109. Markovska, Natasa
    et al.
    Klemes, Jiri Jaromir
    Duic, Neven
    Guzovic, Zvonimir
    Mathiesen, Brian Vad
    Lund, Henrik
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Sustainable development of energy, water and environment systems2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 135, p. 597-599Article in journal (Other academic)
  • 110.
    Martin, Viktoria
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    He, Bo
    Setterwall, Fredrik
    Direct contact PCM-water cold storage2010In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 87, no 8, p. 2652-2659Article in journal (Refereed)
    Abstract [en]

    Comfort cooling demand continues to increase throughout the world Conventional cooling production results in high demand for electrical power during peak hours, leading to high emissions for producing cooling, and potential power shortages in electric grids With a cold storage, the peak power demand is effectively managed and enables free-cooling. This paper examines one concept using phase change materials (PCM) for storing of cold, where the cold carrier (water) is in direct contact with the PCM. This is in order to enable high power for charging and discharging while providing a high storage capacity. A theoretical model highlights important design parameters for reaching large storage and power capacity The capacity increases with the Packing Factor and temperature difference across the storage. For high power, the flow rate, temperature difference, and drop size is important parameters which is also verified in an experimental evaluation. The obtainable power is between 30 and 80 kW/m(3) storage Practical limitations of this concept are shown to be PCM-water bed expansion and non-uniform channeling due to asymmetric and unstable PCM shells.

  • 111.
    Menghwani, Vikas
    et al.
    Univ British Columbia, Inst Resources Environm & Sustainabil, AERL Bldg,429-2202 Main Mall, Vancouver, BC V6T 1Z4, Canada..
    Zerriffi, Hisham
    Univ British Columbia, Forest Sci Ctr, Dept Forest Resources Management, 2424 Main Mall, Vancouver, BC V6T 1Z4, Canada..
    Korkovelos, Alexandros
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Khavari, Babak
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Sahlberg, Andreas
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Howells, Mark
    Loughborough Univ, Dept Geog & Environm, Loughborough LE11 3TU, Leics, England.;Imperial Coll, Ctr Environm Policy, London SW7 1NE, England..
    Mentis, Dimitris
    World Resources Inst, 10 G St NE Suite 800, Washington, DC 20002 USA..
    Planning with justice: Using spatial modelling to incorporate justice in electricity pricing - The case of Tanzania2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 264, article id UNSP 114749Article in journal (Refereed)
    Abstract [en]

    Universal electrification by 2030 is an important goal of Sustainable Development Goal (SDG) 7. Electricity provision no longer relies only on centralized grid expansion, but also on off-grid and mini-grid systems. Although this technological diversity holds promise, the technologies differ both physically and institutionally in electricity delivery. These differences raise equity and justice concerns around how they are implemented. For example, how can electricity be kept affordable for all consumers when access is provided by various technologies operated under different business models? This paper addresses this aspect of affordability and sheds light on how the SDG7 target could be met more equitably and fairly. We use a novel analytical methodology to apply two different principles of justice - equality and equity - to incorporate affordability into electricity pricing. Using a geospatial electrification model and Tanzania as a case study, we first arrive at price levels based on the principle(s) of justice. Then, we produce location-specific recommendations for subsidy levels needed to ensure those price levels. We find that the equity approach benefits a bigger section of the population than the equality approach. Moreover, the former costs significantly less per capita than the latter. Having said that, the equity approach is complex and therefore harder to implement. The methodological framework proposed in this study acts as a proof-of-concept for examining concerns around distributive justice using quantitative energy modelling tools and drawing policy relevant insights for energy planning in developing countries. Additionally, by focusing on the spatial aspects of energy access and the issue of fairness, the study also contributes to the growing conceptualizations of energy justice.

  • 112. Mohan, G.
    et al.
    Kumar, U.
    Pokhrel, M. K.
    Martin, Andrew
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A novel solar thermal polygeneration system for sustainable production of cooling, clean water and domestic hot water in United Arab Emirates: Dynamic simulation and economic evaluation2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 167, p. 173-188Article in journal (Refereed)
    Abstract [en]

    In this paper, a novel solar thermal polygeneration (STP) system for production of cooling, clean water and domestic hot water is modeled and analyzed for the weather conditions of United Arab Emirates (UAE). The system comprises of solar collectors for production of thermal energy, single stage LiBr-H2O absorption chiller (VAC) for providing air conditioning to office cabins and membrane distillation (MD) modules for clean water production along with domestic hot water generation as by-product. The performance of STP is analyzed with three different solar collectors - flat plate collectors (FPC), evacuated tube collector (ETC) and compound parabolic collector (CPC). The system is modeled and dynamically simulated using TRNSYS software for optimization of various design parameters like slope of the collectors, mass flow rate through the collector loop, storage capacity and area of collectors. Combined and system efficiency of the STP system has been determined for optimum conditions. Economic benefits are analyzed for different collectors and fuel costs savings. A lowest payback period of 6.75 years is achieved by STP with evacuated tube collector field having gross area of 216 m2. STP system has cumulative savings of $520,000 over the life time of the project through roof top solar collector installation. In terms of environmental benefits, 109 metric tons/year of CO2 emissions would be avoided and hence the overall payback period would be reduced by 8% based on cost saving through carbon credits. Economic and environmental benefits were aided by steady system performances of absorption chiller (35 kW), membrane distiller (80 l/day) and heat recovery system (1.2 m3/h) throughout the year. The complete simulation results of the STP system is utilized for the development, installation and testing of a polygeneration system at RAKRIC.

  • 113.
    Mohseni, Farzad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Magnusson, Mimmi
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Görling, Martin
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Alvfors, Per
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Biogas from renewable electricity: Increasing a climate neutral fuel supply2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1, p. 11-16Article in journal (Refereed)
    Abstract [en]

    If considering the increased utilisation of renewable electricity during the last decade, it is realistic to assume that a significant part of future power production will originate from renewable sources. These are normally intermittent and would cause a fluctuating electricity production. A common suggestion for stabilising intermittent power in the grid is to produce hydrogen through water electrolysis thus storing the energy for later. It could work as an excellent load management tool to control the intermittency, due to its flexibility. In turn, hydrogen could be used as a fuel in transport if compressed or liquefied. However, since hydrogen is highly energy demanding to compress, and moreover, has relatively low energy content per volume it would be more beneficial to store the hydrogen chemically attached to carbon forming synthetic methane (i.e. biogas). This paper presents how biogas production from a given amount of biomass could be increased by addition of renewable electricity. Commonly biogas is produced through digestion of organic material. Recently also biomass gasification is gaining more attention and is under development. However, in both cases, a significant amount of carbon dioxide is produced as by-product which is subject for separation and disposal. To increase the biogas yield, the separated carbon dioxide (which is considered as climate neutral) could, instead of being seen as waste, be used as a component to produce additional methane through the well-known Sabatier reaction. In such process the carbon could act as hydrogen carrier of hydrogen originating from water electrolysis driven by renewable sources. In this study a base case scenario, describing biogas plants of typical sizes and efficiencies, is presented for both digestion and gasification. It is assessed that, if implementing the Sabatier process on gasification, the methane production would be increased by about 110%. For the digestion, the increase, including process improvements, would be about 74%. Hence, this method results in greatly increased biogas potential without the addition of new raw material to the process. Additionally, such model would present a great way to meet the transport sector's increasing demand for renewable fuels, while simultaneously reducing net emissions of carbon dioxide.

  • 114.
    Molinari, Marco
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Anund Vogel, Jonas
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Rolando, Davide
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Using living labs to tackle innovation bottlenecks: the KTH Live-In Lab case study2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 338, p. 120877-120877, article id 120877Article in journal (Refereed)
    Abstract [en]

    The adoption of innovation in the building sector is currently too slow for the ambitious sustainability goals thatour societies have agreed upon. Living labs are open innovation ecosystems in real-life environments usingiterative feedback processes throughout a lifecycle approach of an innovation to create sustainable impact. In thecontext of the built environment, such co-creative innovation and demonstration platforms are needed tofacilitate the adoption of innovative technologies and concepts for more energy-efficient and sustainablebuildings. However, their feasibility is not extensively proven. This paper illustrates the implementation anddemonstrates the feasibility of the Living Labs Triangle Framework for buildings living labs. This conceptualframework has been used to conceive the KTH Live-In Lab, a living lab for buildings. The goal of the Live-In Labwas to create a co-creative open platform for research and education bridging the gap between industry andacademia, featuring smart building demonstrators. The Living Lab Triangle Framework has been deployed tomeet the goals of the Live-in Lab, and the resulting concept is described. This paper then analyses the meth-odological and operational results introducing performance metrics to measure the economic sustainability, thepromotion of multidisciplinary research and development projects, dissemination and impact. The results arecompleted with a SWOT analysis identifying its current strengths and weaknesses. The results collected in thiswork fill a missing gap in the scientific literature on the performance of living labs and provide empirical evi-dence on the sustainability and impact of living labs.

  • 115.
    Munajat, Nur Farizan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Erlich, Catharina
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fakhrai, Reza
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Fransson, Torsten H.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Influence of water vapour and tar compound on laminar flame speed of gasified biomass gas2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 98, p. 114-121Article in journal (Refereed)
    Abstract [en]

    Biomass can be converted to a gaseous fuel through gasification in order to be used in higher efficiency conversion equipment. Combustion of a gaseous fuel generally allows for higher combustion temperatures than that of a solid fuel leading to the higher efficiency. However, the gasified biomass gas (GBG) contains condensable compounds, such as water vapour and tars, which both will affect the subsequent combustion process with respect to emission levels and flame stability. Cleaning of the GBG prior to combustion is very costly and therefore further research is needed on direct combustion of GBG containing these condensable compounds, in order to develop stable combustion techniques for GBG. The laminar flame speed is a main parameter that relates to other important flame properties such as stability, extinction limit and flashback. Each of GBG components have different chemical and transport properties, which then influences the laminar flame speed of GBG. In this study, the individual effect of water vapour (H2O) and tar compound addition in simulated GBG on laminar flame speed is investigated at atmospheric pressure. The tar compound used is benzene (C6H6) and simulated GBG used is CO/H-2/CH4/CO2/N-2 mixture. Experiments were carried out with conical burner stabilized flame and a Schlieren photography system. The volume fraction of additives in the fuel mixture was varied: for H2O from 0% to 5% and for C6H6 from 0% to 10%. The unburned fuel air mixture was preheated and the temperature was maintained at T-i = 398 K to avoid condensation of the liquid. It was found that measured laminar flame speed of GBG-air mixture decreases with addition of H2O in the fuel mixture. While, non-monotonic behaviour is shown with addition of C6H6. Initially, as the volume fraction of C6H6 incremented, the laminar flame speed decreases, reaching a minimum value, and then increase.

  • 116. Mundaca, Luis
    et al.
    Neij, Lena
    Markandya, Anil
    Hennicke, Peter
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    Towards a Green Energy Economy?: Assessing policy choices, strategies and transitional pathways2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 179, p. 1283-1292Article in journal (Refereed)
    Abstract [en]

    The term 'Green Energy Economy' (GEE) received increasing policy and scientific attention following the 2008-2009 global financial crisis, leading to the implementation of numerous 'Green Growth' economic stimulus packages that targeted low-carbon energy technologies. These initiatives were portrayed as key elements in the transition to a green economy, in which low-carbon energy systems would play a vital role. However, and setting aside conceptual variations, uncertainties and fragmented knowledge remain in the interplay between a green economy, low-carbon energy systems and governance. This research area raises various questions regarding the performance, implications and complexities of policies and strategies addressing GEE transitional pathways. In addition, achieving a GEE compatible with climate, social and economic goals is an enormous challenge for society, and goes beyond the technological domain. This special issue provides a series of articles that critically investigate these concerns from an interdisciplinary point of view, and provide relevant policy insights using a variety of analytical approaches. Overall, they call for strong leadership, ambitious policy instruments, rigorous assessments, effective multi-level governance, inter/national cooperation, institutional capacity development, and the immediate alignment of the financial system with the energy sector on numerous challenges associated with the GEE transition. It is concluded that not only from an environmental point of view, but also due to economic and social reasons, the GEE transition needs to be accelerated and that a radical transformation is required.

  • 117.
    Månsson, André
    et al.
    Lund University, Environmental and Energy Systems Studies.
    Sanches Pereira, Alessandro
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy and Climate Studies, ECS.
    Hermann, Sebastian
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Biofuels for road transport: Analysing evolving supply chains in Sweden from an energy security perspective2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 123, p. 349-357Article in journal (Refereed)
    Abstract [en]

    The use of biofuels for road transport in Sweden has increased during the past 10. years as policymakers stimulate demand in response to concerns about climate change. Using a supply chain approach, this paper analyses: (i) existing biofuel supply chains in Sweden (biogas, biodiesel and bioethanol) in terms of security of supply, and (ii) possibilities to achieve synergies between implementation of climate change mitigation practices and security of supply objectives, through increased production and use of biofuels. We argue that synergies can arise when exposure to upstream market risk decreases, the risk of the feedstock does not correlate with the fuel that it replaces, producers can switch between feedstocks and end user vulnerability to disruptions decreases. In the current Swedish context, the features of the biogas supply chain make it the most beneficial option, followed by biodiesel. In the way it has been implemented, bioethanol is the least favourable option. The paper concludes by outlining how biofuels could contribute to security of supply in the future.

  • 118. Naqvi, M.
    et al.
    Dahlquist, E.
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering. Mälardalen University, Sweden.
    Naqvi, S. R.
    Nizami, A. S.
    Salman, C. A.
    Danish, M.
    Farooq, U.
    Rehan, M.
    Khan, Z.
    Qureshi, A. S.
    Polygeneration system integrated with small non-wood pulp mills for substitute natural gas production2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 224, p. 636-646Article in journal (Refereed)
    Abstract [en]

    This study aims to examine the potential substitute natural gas (SNG) production by integrating black liquor gasification (BLG) island with a small wheat straw-based non-wood pulp mills (NPM), which do not employ the black liquor recovery cycle. For such integration, it is important to first build knowledge on expected improvements in an overall integrated non-wood pulp mill energy system using the key performance indicators. O2-blown circulating fluidized bed (CFB) gasification with direct causticization is integrated with a reference small NPM to evaluate the overall performance. A detailed economic analysis is performed together with a sensitivity analysis based on variations in the rate of return due to varying biomass price, total capital investment, and natural gas prices. The quantitive results showed considerable SNG production but significantly reduced electricity production. There is a substantial CO2 abatement potential combining CO2 capture and CO2 mitigation from SNG use replacing compressed natural gas (CNG) or gasoline. The economic performance through sensitivity analysis reflects significant dependency on both substitute natural gas production and natural gas market price. Furthermore, the solutions to address the challenges and barriers for the successful commercial implementation of BLG based polygeneration system at small NPMs are discussed. The system performance and discussion on the real application of integrated system presented in this article form a vital literature source for future use by large number of small non-wood pulp industries.

  • 119.
    Naqvi, Muhammad Raza
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Department of Chemical Engineering, University of Gujrat, Pakistan .
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. School of Sustainable Development of Society and Technology, Mälardalen University, Sweden .
    Dahlquist, E.
    System analysis of dry black liquor gasification based synthetic gas production comparing oxygen and air blown gasification systems2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 1275-1282Article in journal (Refereed)
    Abstract [en]

    The black liquor gasification based bio-fuel production at chemical pulp mill is an attractive option to replace conventional recovery boilers increasing system energy efficiency. The present paper studies circulating fluidized bed system with direct causticization using TiO2 for the gasification of the black liquor to the synthesis gas. The advantage of using direct causticization is the elimination of energy-intensive lime kiln which is an integral part of the conventional black liquor recovery system. The study evaluates the effects of gasifying medium i.e. oxygen or air, on the fluidized bed gasification system, the synthesis gas composition, and the downstream processes for the synthesis gas conversion to the synthetic natural gas (SNG). The results showed higher synthetic natural gas production potential with about 10% higher energy efficiency using oxygen blown gasification system than the air blown system. From the pulp mill integration perspective, the material and energy balance results in better integration of air blown system than the oxygen blown system, e.g. less steam required to be generated in the power boiler, less electricity import, and less additional biomass requirement. However, the air blown system still requires a significant amount of energy in terms of the synthesis gas handling and gas upgrading using the nitrogen rejection system.

  • 120.
    Naqvi, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Dahlquist, Erik
    School of Sustainable Development of Society and Technology, Mälardalen University, Sweden.
    Bio-refinery system in a pulp mill for methanol production with comparison of pressurized black liquor gasification and dry gasification using direct causticization2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1, p. 24-31Article in journal (Refereed)
    Abstract [en]

    Black liquor gasification (BLG) for bio-fuel or electricity production at the modern pulp mills is a field in continuous evolution and the efforts are considerably driven by the climate change, fuel security, and renewable energy. This paper evaluates and compares two BLG systems for methanol production: (i) oxygen blown pressurized thermal BLG; and (ii) dry BLG with direct causticization, which have been regarded as the most potential technology candidates for the future deployment. A key objective is to assess integration possibilities of BLG technologies with the reference Kraft pulp mill producing 1000 air dried tonnes (ADt) pulp/day replacing conventional recovery cycle. The study was performed to compare the systems’ performance in terms of potential methanol production, energy efficiency, and potential CO2 reductions. The results indicate larger potential of black liquor conversion to methanol from the pressurized BLG system (about 77 million tonnes/year of methanol) than the dry BLG system (about 30 million tonnes/year of methanol) utilizing identical amount of black liquor available worldwide (220 million tDS/year). The potential CO2 emissions reduction from the transport sector is substantially higher in pressurized BLG system (117 million tonnes/year CO2 reductions) as compared to dry BLG system (45 million tonnes/year CO2 reductions). However, the dry BLG system with direct causticization shows better results when considering consequences of additional biomass import. In addition, comparison of methanol production via BLG with other bio-refinery products, e.g. hydrogen, dimethyl ether (DME) and bio-methane, has also been discussed.

  • 121.
    Naqvi, Muhammad
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Dahlquist, Erik
    School of Sustainable Development of Society and Technology, Mälardalen University, Sweden.
    Synthetic gas production from dry black liquor gasification process using direct causticization with CO2 capture2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 97, p. 49-55Article in journal (Refereed)
    Abstract [en]

    Synthetic natural gas (SNG) production from dry black liquor gasification (DBLG) system is an attractive option to reduce CO2 emissions replacing natural gas. This article evaluates the energy conversion performance of SNG production from oxygen blown circulating fluidized bed (CFB) black liquor gasification process with direct causticization by investigating system integration with a reference pulp mill producing 1000 air dried tonnes (ADt) of pulp per day. The direct causticization process eliminates use of energy intensive lime kiln that is a main component required in the conventional black liquor recovery cycle with the recovery boiler. The paper has estimated SNG production potential, the process energy ratio of black liquor (BL) conversion to SNG, and quantified the potential CO2 abatement. Based on reference pulp mill capacity, the results indicate a large potential of SNG production (about 162 MW) from black liquor but at a cost of additional biomass import (36.7 MW) to compensate the total energy deficit. The process shows cold gas energy efficiency of about 58% considering black liquor and biomass import as major energy inputs. About 700 ktonnes per year of CO2 abatement i.e. both possible CO2 capture and CO2 offset from bio-fuel use replacing natural gas, is estimated. Moreover, the SNG production offers a significant fuel replacement in transport sector especially in countries with large pulp and paper industry e.g. in Sweden, about 72% of motor gasoline and 40% of total motor fuel could be replaced.

  • 122. Naqvi, Muhammad
    et al.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    Dahlquist, Erik
    Naqvi, Salman Raza
    Off-grid electricity generation using mixed biomass compost: A scenario-based study with sensitivity analysis2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 201, p. 363-370Article in journal (Refereed)
    Abstract [en]

    The aim of the study is to investigate the viability of waste gasification based off-grid electricity generation utilizing mixed biomass composts (mixture of rice hulls with cow/poultry manure compost). The economic viability is studied on the different scenarios with considerations of (1) levels of electricity demand and utilization, (2) costs of variable biomass mix, (3) combined domestic and cottage industry business model, and (4) influence of governmental investments. The levelized cost of electricity (LCOE) is used as an indicator to measure the competitiveness of gasification based off-grid electricity generation. The plant loading and the capacity factor have been used to assess the impacts of different scenarios. A sensitivity analysis of key parameters based on variations in annual operational hours, plant efficiency, plant cost and biomass supply cost is conducted. Based on levels of electricity demand and utilization, the LCOE ranged between 40 US cents/kW h and 29 US cents/kW h based on the plant loading and the capacity factor. The business revenue would not change considerably despite better plant utilization and reduced levelized cost of electricity if all the consumers, both basic or medium, are charged with the flat tariff. The part load operation will be costly despite considerably low capital investment per kW in comparison with PV or solar based plants. There is a large potential of off-grid electricity generation but the estimated off-grid electricity price is found to be higher in all scenarios than average grid-based electricity tariff. Moreover, the challenges for the implementation of the real off-grid electricity generation plant are discussed.

  • 123. Nemet, Andreja
    et al.
    Klemes, Jiri Jaromir
    Duic, Neven
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology. Malardalen University (MDU), Sweden.
    Improving sustainability development in energy planning and optimisation2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 184, p. 1241-1245Article in journal (Refereed)
    Abstract [en]

    This special issue of Applied Energy contains articles developed from initial ideas related to the 10th Conference on Sustainable Development of Energy, Water and Environment Systems (SDEWES) held in Dubrovnik, Croatia during September 27 - October 2, 2015. The main focus of the event is the sustainability development joining all required areas for achieving as improving the knowledge on method, policies and technologies as well as dissemination of the results. Overall, 64 extended manuscripts have been invited as candidate articles. After a thorough review procedure, 23 articles have been selected to be published. The topics attained in the focus of this Special Issue include Integration, Optimisation and Analysis of energy systems as well as dissemination of the developed methodology and results obtained.

  • 124.
    Nilsson, Måns
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms). Stockholm Environment Institute, Sweden.
    Nykvist, B.
    Governing the electric vehicle transition - Near term interventions to support a green energy economy2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 179, p. 1360-1371Article in journal (Refereed)
    Abstract [en]

    This paper seeks to better understand how one plausible development in a green energy economy transition of the transport sector can be governed: a breakthrough of battery-electric vehicles (BEV). Drawing on recent results and lessons from BEV studies at local, national and regional scales, the paper presents two alternative scenarios of BEV uptake until 2030 - one incremental growth scenario and one breakthrough scenario. It then draws on the multilevel perspective (MLP) on socio-technical systems as an approach to identify the governance implications of the breakthrough scenario. Based on a characterisation of barriers and drivers at landscape, regime and niche levels, it identifies governance interventions to enable a BEV breakthrough. The results point towards a multidimensional governance approach that includes conventional policy instruments such as durable incentive policies, with a predictable mechanism for adjustment and phase-out, and mechanisms for mobilising investment finance for fast and super-fast charging and home charging along public roads. In addition, more innovation-systems oriented governance is required, such as familiarisation and experience building to ease cognitive barriers and build knowledge for both consumers and businesses, and supporting structural and technological change within automotive industries.

  • 125.
    Novalin, Timon
    et al.
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Eriksson, Björn
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Proch, Sebastian
    Alleima, Strateg Res, SE-81181 Sandviken, Sweden..
    Bexell, Ulf
    SSAB EMEA AB, Prod Dev, S-78184 Borlänge, Sweden..
    Moffatt, Claire
    Alleima, Strateg Res, SE-81181 Sandviken, Sweden..
    Westlinder, Jorgen
    Alleima, Strateg Res, SE-81181 Sandviken, Sweden..
    Lagergren, Carina
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Lindbergh, Göran
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Wreland Lindström, Rakel
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Applied Electrochemistry.
    Demonstrating the absence of metal ion contamination in operando PEM fuel cells utilizing unmodified stainless steel bipolar plates2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 349, article id 121669Article in journal (Refereed)
    Abstract [en]

    Using stainless steel as material for bipolar plates (BPPs) in proton exchange membrane fuel cells (PEMFCs) carries a perceived risk of corrosion and subsequent metal ion contamination of the membrane electrode as-sembly (MEA). However, assessments in literature on this hazard to PEMFC systems have been based on ex-situ corrosion studies, where general assumptions made on the BPP environment might not be a correct simulation of real on-site conditions. In this contribution, uncoated BPPs from stainless steel grades 304 L, 316 L and 904 L were subjected to in-situ hybrid endurance/stress testing to simulate realistic conditions in operating fuel cell systems and re-evaluate the need of additional corrosion protection. A post analysis of the plates showed no signs of surface dissolution on any of the tested samples and the concentration of iron in the MEA averaged 7 to 10 ppm for uncoated samples and 7 to 11 ppm for coated and graphitic reference tests, displaying a negligible amount of trace metals compared to critical thresholds found in literature. Contact resistance values were stable for all samples and observable changes in cell performance and voltage degradation was confirmed to be un-related to the presence of uncoated bipolar plates. The combined effects of decoupling of bipolar plate surface potentials from electrode potentials and operational control of stable gas flow compositions to sustain stainless steel surface passivation, were identified as explanation for the experimentally observed corrosion resistance of uncoated stainless steel plates in PEMFCs.

  • 126.
    Olsson, Alexander
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Campana, Pietro Elia
    Lind, Mårten
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden .
    Potential for carbon sequestration and mitigation of climate change by irrigation of grasslands2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 136, p. 1145-1154Article in journal (Refereed)
    Abstract [en]

    The climate change mitigation potential of irrigation powered by a photovoltaic water pumping system (PVWPS) to restore degraded grasslands has been investigated using the Intergovernmental Panel on Climate Change (IPCC) 2006 Guidelines for National Greenhouse Gas Inventories for Agriculture, Forestry and Other Land Use. The purpose of this study is to develop a generic and simple method to estimate the climate change mitigation benefit of a PVWPS. The possibility to develop carbon credits for the carbon offset markets has also been studied comparing carbon sequestration in grasslands to other carbon sequestration projects. The soil carbon sequestration following irrigation of the grassland is calculated as an annual increase in the soil organic carbon pool. The PVWPS can also generate an excess of electricity when irrigation is not needed and the emissions reductions due to substitution of grid electricity give additional climate change mitigation potential. The results from this study show that the carbon sequestration and emissions reductions benefits per land area using a PVWPS for irrigating grasslands are comparable to other carbon sequestration options such as switching to no-till practice. Soil carbon in irrigated grasslands is increased with over 60% relative to severely degraded grasslands and if nitrogen fixing species are introduced the increase in soil organic carbon can be almost 80%. Renewable electricity generation by the PVWPS will further increase the mitigation benefit of the system with 70-90%. When applying the methodology developed in this paper to a case in Qinghai, China, we conclude that using a PVWPS to restore degraded grasslands for increased grass production and desertification control has a climate change mitigation benefit of 148 Mg (1 Mg = 1 metric ton) CO2-equivalents (CO2-eq) per hectare in a cold temperate, dry climate during a 20 year process of soil organic carbon sequestration and emissions reductions. Leakage due to an increase in N2O emissions from the additional biomass production and introduction of nitrogen fixing species is included in this result. The most important conclusion from our case is that if soil carbon sequestration is lower than 24 Mg CO2-eq per hectare including leakage, then the climate change mitigation benefit is larger if PV is used to produce electricity for the grid.

  • 127.
    Oró, Eduard
    et al.
    GREA UdL.
    Castell, Albert
    GREA UdL.
    Chiu, Justin NingWei
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Martin, Viktoria
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Cabeza, Luisa
    GREA UdL.
    Stratification analysis in packed bed thermal energy storage systems2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, no SI, p. 476-487Article in journal (Refereed)
    Abstract [en]

    District cooling and heating networks are increasing in many countries, especially in the Scandinavian countries. Some of the systems have become small for the needs of the population and they have to be enhanced in order to reach the cooling or heating necessities. Here, thermal energy storage system of a district cooling network is studied. Phase change material (PCM) is used in order to enhance the energy density and the stratification of the water tank. The experimental set up consists mainly of a cylindrical storage tank with a capacity of 3.73 L filled with spherically encapsulated PCM. The PCM used is PK6 from Rubitherm GmbH with a storage capacity of 175 kJ/kg between −2 °C and 13 °C. Many methods to characterize water tank stratification, such as graphical (dimensional and non-dimensional) and numerical figures based on temperature distribution (degree of stratification, first law efficiencies, second law efficiencies, other efficiencies as MIX number), are used to analysed and characterized two storage tanks, one of them with the inclusion of PCM packed bed during both charging and discharging processes.

  • 128.
    Pan, Gechuanqi
    et al.
    Sun Yat Sen Univ, Sch Data & Comp Sci, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Mat Sci & Engn, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Intelligent Syst Engn, Guangzhou, Peoples R China.;Natl Supercomp Ctr Guangzhou, Guangzhou, Peoples R China..
    Wei, Xiaolan
    South China Univ Technol, Sch Chem & Chem Engn, Guangzhou, Peoples R China..
    Yu, Chao
    Sun Yat Sen Univ, Sch Data & Comp Sci, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Mat Sci & Engn, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Intelligent Syst Engn, Guangzhou, Peoples R China..
    Lu, Yutong
    Sun Yat Sen Univ, Sch Data & Comp Sci, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Mat Sci & Engn, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Intelligent Syst Engn, Guangzhou, Peoples R China.;Natl Supercomp Ctr Guangzhou, Guangzhou, Peoples R China..
    Li, Jiang
    Natl Supercomp Ctr Guangzhou, Guangzhou, Peoples R China..
    Ding, Jing
    Sun Yat Sen Univ, Sch Data & Comp Sci, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Mat Sci & Engn, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Intelligent Syst Engn, Guangzhou, Peoples R China..
    Wang, Weilong
    Sun Yat Sen Univ, Sch Data & Comp Sci, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Mat Sci & Engn, Guangzhou, Peoples R China.;Sun Yat Sen Univ, Sch Intelligent Syst Engn, Guangzhou, Peoples R China..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Thermal performance of a binary carbonate molten eutectic salt for high-temperature energy storage applications2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 262, article id 114418Article in journal (Refereed)
    Abstract [en]

    Molten carbonate eutectic salts are promising thermal storage and heat transfer fluid materials in solar thermal power plant with the feature of large specific heat capacity, wide operating temperature range and little corrosive. The high-temperature properties of molten carbonates should be determined accurately over the entire operating temperature for energy system design. In this paper, molecular dynamic simulation is used to study temperature and component dependence of microstructures and thermophysical properties of the binary carbonate molten salt. Negative linear temperature dependence of densities and thermal conductivities of binary mixtures of different components is confirmed with respect to the distances of ion clusters. Besides, positive linear temperature dependence of self-diffusion coefficient is also obtained. When temperature is constant, densities and thermal conductivities of binary mixtures are linearly related with components. Self-diffusion coefficients of CO32- firstly increase and then decrease with increasing mole fraction of Na2CO3. The temperature-thermophysical properties-composition correlation formulas are obtained, and the database of thermophysical properties of molten carbonate salts over the entire operating temperature is complemented, which will provide the essential data for heat transfer and storage system design, operation, and optimization in CSP.

  • 129.
    Papageorgiou, Asterios
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Ashok, Archana
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Hashemi Farzad, Tabassom
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Sundberg, Cecilia
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Resources, Energy and Infrastructure.
    Climate change impact of integrating a solar microgrid system into the Swedish electricity grid2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 268, article id 114981Article in journal (Refereed)
    Abstract [en]

    Microgrids are small-scale electricity networks that integrate distributed electricity generation with consumers and, potentially, with storage devices. There is growing interest in these systems, as they can offer solutions for electrification of remote areas, deployment of distributed renewable energy resources, and decarbonization of electricity supply. However, the potential benefits of microgrids in terms of climate change mitigation have not yet been thoroughly assessed. In this study, Life Cycle Assessment was performed to determine the climate change impact of integrating a solar microgrid system in western Sweden into the Swedish electricity grid. To determine whether replacement of grid electricity with electricity from the microgrid can lower greenhouse gas (GHG) emissions, average and marginal GHG emission factors (EFs) for electricity use were estimated with explicit spatial and temporal resolution, using historical data on electricity generation and trade, and life cycle EFs for electricity generation technologies. The assessment, with both marginal and average EFs, showed that integration of the microgrid into the Swedish electricity grid did not provide GHG emissions abatements, as the electricity from the microgrid displaced grid electricity with lower carbon intensity. It was found that a microgrid without batteries would have lower climate change impact, but would still fail to lower overall GHG emissions. Moreover, it was demonstrated that the methodological approach used for estimation of EFs and the definition of spatial boundaries could influence the obtained results.

  • 130.
    Parisio, Alessandra
    et al.
    KTH, School of Electrical Engineering (EES), Automatic Control. KTH, School of Electrical Engineering (EES), Centres, ACCESS Linnaeus Centre.
    Rikos, Evangelos
    Tzamalis, George
    Glielmo, Luigi
    Use of Model Predictive Control for Experimental Microgrid Optimization2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 115, p. 37-46Article in journal (Refereed)
    Abstract [en]

    In this paper we deal with the problem of efficiently optimizing microgrid operations while satisfying a time-varying request and operation constraints. Microgrids are subsystems of the distribution grid comprising sufficient generating resources to operate in isolation from the main grid, in a deliberate and controlled way. The Model Predictive Control (MPC) approach is applied for achieving economic efficiency in microgrid operation management. The method is thus applied to an experimental microgrid located in Athens, Greece: experimental results show the feasibility and the effectiveness of the proposed approach.

  • 131.
    Peng, Jinqing
    et al.
    Hunan Univ, Coll Civil Engn, Changsha 410082, Hunan, Peoples R China.;Hunan Univ, Minist Educ, Key Lab Bldg Safety & Energy Efficiency, Changsha 410082, Hunan, Peoples R China..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes. Mälardalen Univ, Sch Business Soc & Engn, S-72123 Västerås, Sweden..
    Zhai, Zhiqiang
    Univ Colorado, Dept Civil Environm & Architectural Engn, Boulder, CO 80309 USA..
    Markides, Christos N.
    Imperial Coll London, Dept Chem Engn, Clean Energy Proc CEP Lab, London SW7 2AZ, England..
    Lee, Eleanor S.
    Lawrence Berkeley Natl Lab, Bldg Technol & Urban Syst Div, Mailstop 90-3111,1 Cyclotron Rd, Berkeley, CA 94720 USA..
    Eicker, Ursula
    Stuttgart Univ Appl Sci, Res Ctr Sustainable Energy Technol Zafh Net, D-70174 Stuttgart, Germany..
    Zhao, Xudong
    Univ Hull, Res Ctr Sustainable Energy Technol, Kingston Upon Hull HU6 7RX, N Humberside, England..
    Kuhn, Tilmann E.
    Fraunhofer Inst Solar Energy Syst ISE, Heidenhofstr 2, D-79110 Freiburg, Germany..
    Sengupta, Manajit
    Natl Renewable Energy Lab, Power Syst Engn Ctr, Golden, CO 80401 USA..
    Taylor, Robert A.
    Univ New South Wales, Sch Photovolta & Renewable Energy Engn, Sch Mech & Mfg Engn, Sydney, NSW 2052, Australia..
    Solar energy integration in buildings2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 264, article id UNSP 114740Article in journal (Other academic)
  • 132.
    Pereverza, Kateryna
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Pasichnyi, Oleksii
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Lazarevic, David
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology. Environmental Policy Centre, Finnish Environment Institute SYKE.
    Kordas, Olga
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Strategic planning for sustainable heating in cities: A morphological method for scenario development and selection2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 186, no Part 2, p. 1115-1125Article in journal (Refereed)
    Abstract [en]

    The transition to more sustainable heating systems requires socio-technical approaches to strategic planning. Scenario development plays a key role in strategic planning, as the process supports the development of future visions and actions required for their realisation. However, new approaches to scenario development are required to address the limitations of conventional scenario development methods, such as the cognitive barriers of ‘groupthink’, reluctance to consider ‘outside-the-box’ options, handling of complexity, and ad hoc scenario selection and general non-transparency of scenario development processes. This paper describes the development and implementation of a novel method for scenario development and selection in the context of participatory strategic planning for sustainable heating in cities. The method is based on the morphological approach and a number of scenario criteria including transparency,reliabilitycoveragecompletenessrelevance/densitycreativityinterpretabilityconsistencydifferentiation and plausibility. It integrates creativity workshops and interdisciplinary stakeholder participation to enhance the ownership and legitimacy of the scenarios. The approach entails the generation of a complete space of scenarios for heating systems and reduction of this space using cross-consistency analysis and project-specific requirements. Iterative development and implementation of the method is illustrated using two participatory backcasting projects focused on strategic planning for providing a comfortable indoor climate for Bila Tserkva, Ukraine, and Niš, Serbia by the year 2030. The results demonstrate that the method helps overcome the limitations of conventional approaches to scenario development and supports rigorous and transparent selection of a scenario set for participatory analysis. The method fostered the elicitation of consensus-based scenarios for more sustainable heating systems in both cities with regard to the quality of indoor comfort, environmental impact, resource efficiency and energy security.

  • 133.
    Persson, Johannes
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Westermark, Mats
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Low-energy buildings and seasonal thermal energy storages from a behavioral economics perspective2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 112, p. 975-980Article in journal (Refereed)
    Abstract [en]

    The seasonal thermal energy storage technology for domestic heating applications is not enjoying the same increasing market penetration as the smaller diurnal thermal energy storage technology. Although high efficiencies are to expect with seasonal thermal energy storages, high up-front costs are likely to constitute an efficient market barrier, impeding the growth of this technology. This paper analyses the application of seasonal thermal energy storages and other, more conventional heating alternatives on passive houses and standard houses from a behavioral economics perspective. The results show that when the seasonal thermal energy storage technology is applied to passive houses, more competitive investment and annual costs can be offered.

  • 134.
    Poppi, Stefano
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Solar Energy Research Center (SERC), Dalarna University College, Sweden.
    Bales, C.
    Haller, M. Y.
    Heinz, A.
    Influence of boundary conditions and component size on electricity demand in solar thermal and heat pump combisystems2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 162, p. 1062-1073Article in journal (Refereed)
    Abstract [en]

    Solar thermal and heat pump combisystems are used to produce domestic hot water (DHW) and space heating (SH) in dwellings. Many systems are available on the market. For an impartial comparison, a definite level of thermal comfort should be defined and ensured in all systems. This work studied the influence of component size on electricity demand for a state of the art solar thermal and heat pump system. A systematic series of parametric studies was carried out by using TRNSYS to show the impact of climate, load and size of main components as well as heat source for the heat pump. Penalty functions were used to ensure that all variations provided the same comfort requirements. Two reference systems were defined and modelled based on products on the market, one with ambient air and the other with borehole as heat source for the heat pump. The results show that changes in collector area from 5 to 15m2 result in a decrease in system electricity of between 305 and 552kWh/year. Changes in heat exchanger size for DHW preparation were shown to give nearly as large changes in electricity use due to the fact that the set temperature in the store was changed to give the same thermal comfort in all cases. Decrease in heat pump size was shown to give a decrease in electricity use for the ASHP in the building with larger heat demand while it increased or had only a small change for other boundary conditions. Heat pump losses were shown to be an important factor highlighting the importance of modelling this factor explicitly.

  • 135.
    Poppi, Stefano
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology. Dalarna University College, Sweden.
    Bales, C.
    Heinz, A.
    Hengel, F.
    Chèze, D.
    Mojic, I.
    Cialani, C.
    Analysis of system improvements in solar thermal and air source heat pump combisystems2016In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 173, p. 606-623Article in journal (Refereed)
    Abstract [en]

    A solar thermal and heat pump combisystem is one of many system alternatives on the market for supplying domestic hot water (DHW) and space heating (SH) in dwellings. In this study a reference solar thermal and air source heat pump combisystem was defined and modelled based on products available on the market. Based on the results of an extensive literature survey, several system variations were investigated to show the influence of heat pump cycle, thermal storage and system integration on the use of electricity for two houses in the climates of Zurich and Carcassonne. A singular economic cash flow analysis was carried out and the "additional investment limit" of each system variation was determined for a range of economic boundary conditions. This is the maximum extra investment cost for the system variant compared to the reference system that will give a break even result for a 10 year period. The results show that variations in electricity price affects the additional investment limit far more than the other economic parameters. Several of the variants show potential for achieving a cost benefit, but the potential varies a lot depending on load and climate boundary conditions. For all variants, the biggest difference in electricity savings was found for Zurich rather than in Carcassonne, which is explained by the larger heating load. However, in three cases the largest savings were for the SFH45 house despite the fact that the annual electricity use of the system is much lower than that for the SFH100 house, 3581 kW h/year compared to 8340 kW h/year. This was attributed to the fact that, in these cases, the operating level of the space heating circuit played a significant role, the SFH45 house being supplied with a 35/30 °C heating system while the SFH100 was supplied with a 55/45 °C heating system.

  • 136. Roskilly, A. P.
    et al.
    Palacin, R.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    Novel technologies and strategies for clean transport systems2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 157, p. 563-566Article in journal (Other academic)
  • 137. Roskilly, A. P.
    et al.
    Taylor, P. C.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Energy storage systems for a low carbon future - in need of an integrated approach2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 137, p. 463-466Article in journal (Other academic)
  • 138.
    Ruan, Tianqi
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Fuxing
    Swedish Meteorological and Hydrological Institute, Folkborgsvägen 17, 60176, Norrköping, Sweden, Folkborgsvägen 17.
    Topel, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Laumert, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Wang, Wujun
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    A new optimal PV installation angle model in high-latitude cold regions based on historical weather big data2024In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 359, article id 122690Article in journal (Refereed)
    Abstract [en]

    PV technologies are regarded as one of the most promising renewable options for the transition towards Net Zero. Despite the rapid development of PV systems in recent years, achieving the necessary goals requires more than a threefold increase in annual capacity deployment by 2030. However, current PV systems often fall short of optimal performance due to improper installation angles. In high-latitude cold regions, the actual PV generation capacity is frequently overestimated due to the omission of snow conditions. This study introduces a novel model designed for high-latitude regions to predict local optimal PV installation angle that maximizes PV power generation, utilizing historical weather big data, including snowfall and melting effects. A case study is presented within a Swedish context to demonstrate the implementation of these methods. The results highlight the crucial role snow conditions play in determining PV performance, resulting in an average reduction of 14.7% in annual PV power generation. Optimal installation angle could yield approximately a 4.8% improvement compared to common installation angles. The study also explores the application of snow removal agents, which could potentially increase PV generation by 0.1–2.3%. Additionally, the new PV installation angle successfully captures the impact of the local weather changes on PV power generation, potentially serving as a bridge between climate change adaptation and future PV power generation endeavors.

  • 139. Ruiz-Calvo, F.
    et al.
    De Rosa, M.
    Acuna, José
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Corberan, J. M.
    Montagud, C.
    Experimental validation of a short-term Borehole-to-Ground (B2G) dynamic model2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 140, p. 210-223Article in journal (Refereed)
    Abstract [en]

    The design and optimization of ground source heat pump systems require the ability to accurately reproduce the dynamic thermal behavior of the system on a short-term basis, specially in a system control perspective. In this context, modeling borehole heat exchangers (BHEs) is one of the most relevant and difficult tasks. Developing a model that is able to accurately reproduce the instantaneous response of a BHE while keeping a good agreement on a long-term basis is not straightforward. Thus, decoupling the short-term and long-term behavior will ease the design of a fast short-term focused model. This work presents a short-term BHE dynamic model, called Borehole-to-Ground (B2G), which is based on the thermal network approach, combined with a vertical discretization of the borehole. The proposed model has been validated against experimental data from a real borehole located in Stockholm, Sweden. Validation results prove the ability of the model to reproduce the short-term behavior of the borehole with an accurate prediction of the outlet fluid temperature, as well as the internal temperature profile along the U-tube.

  • 140. Salman, C. A.
    et al.
    Naqvi, M.
    Thorin, E.
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH). Mälardalen University, Sweden.
    Gasification process integration with existing combined heat and power plants for polygeneration of dimethyl ether or methanol: A detailed profitability analysis2018In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 226, p. 116-128Article in journal (Refereed)
    Abstract [en]

    Combustion of waste for cogeneration of heat and power is the most convenient and practical choice to carry out through combined heat and power (CHP) plants. But, seasonal variation in heat demand throughout the year affects the operation of CHP plants. This fluctuation in the CHP operation cause less annual operating hours for the plant equipment and is also not profitable for stakeholders. This study aims to assess the technical potential of integrated gasification process with existing CHP plants for either dimethyl ether (DME) or methanol production through refuse-derived fuel (RDF). Process integration considers that the CHP plant provides the necessary heat for biofuel synthesis during off-peak hours. Mass and heat integration methods are used to develop and simulate the polygeneration processes for heat, power, and biofuel production. Both technical and economic indicators are reported and compared to assess the potential for both biofuels through process integration. Annual operation data of a real CHP plant has been extracted to evaluate the integrated processes. A flexible gasification configuration is selected for the integrated approach i.e. CHP runs at full load to provide the heat demand and only the excess heat of CHP plant is utilized for biofuel production. The energetic efficiencies of the polygeneration systems are compared with the standalone systems. Technical analysis of process integration shows the enhancement of the operational capacity of CHP during off-peak hours and it can produce biofuels without compromising the annual heat demand. Production of methanol through process integration shows ∼67% energetic efficiency while methanol production gives ∼65%. The efficiencies are higher than standalone DME and methanol processes (51% and 53%, respectively) but lower than standalone CHP plant i.e. 81%, however the process integration increases the operating time of the CHP plant with more economic benefits. Economic analysis coupled with uncertainty analysis through Monte Carlo simulations shows that by integrating CHP with gasifier to produce biofuels is significantly profitable as compared with only heat and electricity production. But, DME as a potential product shows more economic benefits than methanol. The uncertainty analysis through Monte Carlo simulations shows that the profitable probability of DME as a product in future is also greater than methanol due to higher DME selling price. The uncertainty analysis further shows that prices of DME and methanol with waste biomass prices in future will have a greater impact on the economic performance of the proposed polygeneration process.

  • 141. Salman, C. A.
    et al.
    Schwede, S.
    Thorin, E.
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes. Mälardalen University, Sweden.
    Enhancing biomethane production by integrating pyrolysis and anaerobic digestion processes2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 204, p. 1074-1083Article in journal (Refereed)
    Abstract [en]

    The anaerobic digestion of source-separated organic waste is a mature and increasingly used process for biomethane production. However, the efficient use of different fractions of waste is a big concern in anaerobic digestion plants. This study proposes the use of a new process configuration that couples the anaerobic digestion of biodegradable waste with the pyrolysis of lignocellulosic or green waste. The biochar obtained from pyrolysis was added to a digester as an adsorbent to increase the biomethane content and to support the development of a stable microbial community. In addition, the bio-oil and syngas produced by the pyrolysis process were reformed into syngas and then converted to biomethane via methanation. Modelling and simulations were performed for the proposed novel process. The results showed an approximately 1.2-fold increase in the biomethane volume produced. An overall efficiency of 67% was achieved, whereas the stand-alone anaerobic digestion system had an efficiency of only 52%. The results also indicated a high annual revenue for the integrated process compared to that for an alternative treatment (incineration) of green waste.

  • 142.
    Sandels, Claes
    et al.
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Brodén, Daniel
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Widén, Joakim
    Nordström, Lars
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Andersson, Enar
    SP Technical Research Institute.
    Modeling Office Building Consumer Load with a Combined Physical and Behavioral Approach: Simulation and Validation2015In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 162, p. 472-485Article in journal (Refereed)
    Abstract [en]

    Due to an expanding integration of renewable energy resources in the power systems, mismatches between electricity supplyand demand will increase. A promising solution to deal with these issues is Demand Response (DR), which incentives end-users to be flexible in their electricity consumption. This paper presents a bottom up simulation model that generates office building electricity load profiles representative for Northern Europe. The model connects behavioral aspects of office workers with electricity usage from appliances, and physical representation of the building to describe the energy use of the Heating Ventilation and Air Conditioning systems. To validate the model, simulations are performed with respect to two data sets, and compared with real load measurements. The validation shows that the model can reproduce load profiles with reasonable accuracy for both data sets. With the presented model approach, it is possible to define simple portfolio office building models which subsequently can be used for simulation and analysis of DR in the power systems.

  • 143.
    Sandels, Claes
    et al.
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Widén, Joakim
    Uppsala Universitet.
    Nordström, Lars
    KTH, School of Electrical Engineering (EES), Industrial Information and Control Systems.
    Forecasting household consumer electricity load profiles with a combined physical and behavioral approach2014In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 131, p. 267-278Article in journal (Refereed)
    Abstract [en]

    In this paper, a simulation model that forecasts electricity load profiles for a population of Swedish households living in detached houses is presented. The model is constructed of three separate modules, namely appliance usage, Domestic Hot Water (DHW) consumption and space heating. The appliance and DHW modules are based on non-homogenous Markov chains, where household members move between dierent states with certain probabilities over the days. The behavior of individuals is linked to various energy demanding activities at home. The space heating module is built on thermodynamical aspects of the buildings, weather dynamics, and the heat loss output from the aforementioned modules. Subsequently, a use case for a neighborhood of detached houses in Sweden is simulated using a Monte Carlo approach. For the use case, a number of justified assumptions and parameter estimations are made. The simulations results for the Swedish use case show that the model can produce realistic power demand profiles. The simulated profile coincides especially well with the measured consumption during the summer time, which confirms that the appliance and DHW modules are reliable. The deviations increase for some periods in the winter period due to, e.g. unforeseen end-user behavior during occasions of extreme electricity prices.

  • 144.
    Shabani, Masoume
    et al.
    School of Business, Society & Engineering, Future Energy Center, Mälardalen University, Västerås, Sweden.
    Dahlquist, Erik
    School of Business, Society & Engineering, Future Energy Center, Mälardalen University, Västerås, Sweden.
    Wallin, Fredrik
    School of Business, Society & Engineering, Future Energy Center, Mälardalen University, Västerås, Sweden.
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes. School of Business, Society & Engineering, Future Energy Center, Mälardalen University, Västerås, Sweden.
    Techno-economic comparison of optimal design of renewable-battery storage and renewable micro pumped hydro storage power supply systems: A case study in Sweden2020In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 279, article id 115830Article in journal (Refereed)
    Abstract [en]

    In this study, two types of energy storages are integrated,—namely, micro pumped hydro storage (micro-PHS), and battery storage—into small-scale renewable energy systems for assessing efficiency, cost, maturity, and storage duration.Optimal design of standalone renewable-micro PHS and -battery storage systems for a remote area in Sweden is conducted to find the most suitable solution by considering techno-economic performance indicators such as investment cost, life cycle cost, levelized cost of energy, loss of power supply probability, monthly and annual oversupply, and annual ratio of renewable power to supply power. Number of photovoltaic (PV) modules, number of wind turbines (for renewable energy section), installation height of the upper reservoir, volume of reservoir, pipes diameter, depth to diameter ratio of reservoir, turbine capacity, pump capacity (for PHS section), and battery capacity (for battery storage section) constitute the set of design variables and modified non-dominated sorting Genetic Algorithm is employed as the optimization algorithm. The results show that, for the optimal design with the full satisfaction of power demand, the hybrid PV-wind-battery storage system is the best option in terms of economic benefits and reliability, leading to 18.61% lower life cycle cost and 6.12% lower oversupply, compared to the hybrid PV-wind-micro PHS system. However, the design of both hybrid PV-battery storage and PV-micro PHS systems could be considered fully satisfactory designs led to much higher annual oversupply and much higher life cycle cost in comparison with the PV-Wind-battery storage system.

  • 145.
    Shang, Nan
    et al.
    Zhejiang Univ, Coll Elect Engn, Hangzhou 310058, Zhejiang, Peoples R China..
    Lin, You
    Zhejiang Univ, Coll Elect Engn, Hangzhou 310058, Zhejiang, Peoples R China..
    Ding, Yi
    Zhejiang Univ, Coll Elect Engn, Hangzhou 310058, Zhejiang, Peoples R China..
    Ye, Chengjin
    Zhejiang Univ, Coll Elect Engn, Hangzhou 310058, Zhejiang, Peoples R China..
    Yan, Jinyue
    KTH, School of Engineering Sciences in Chemistry, Biotechnology and Health (CBH), Chemical Engineering, Energy Processes.
    Nodal market power assessment of flexible demand resources2019In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 235, p. 564-577Article in journal (Refereed)
    Abstract [en]

    With the incorporation of higher shares of intermittent renewable energies (RES), more flexible resources are required in power systems to keep load balance. Under some extreme circumstances, the flexible demand resources (FDRs) may have the potential to dominate and obtain excess benefits, preventing other FDRs from participating in the electricity markets. Therefore, it is of great significance to identify the key FDR market power locations and implement some corresponding regulations. However, the relevant researches in power systems focused on the supply side, rather than the demand side. In this paper, a novel nodal market power analysis method is proposed to evaluate the potential influence of FDRs on electricity markets. Firstly, a multi-state model is established to present the multiple power system operation states including the random failures of system components. Then, the nodal market power assessment model is established under each specific state and new indices are proposed to evaluate the nodal market power of FDRs quantitatively. Furthermore, the key FDR nodes in demand side with stronger power in capturing excess revenue are identified. The 24-bus IEEE Reliability Test System is modified to demonstrate the feasibility of the proposed method. The numerical results of the proposed method are capable to display the existence of market power in demand side, and provide some valuable guidance for classification and operation of electricity markets.

  • 146.
    Sharf, Miel
    et al.
    KTH, School of Electrical Engineering and Computer Science (EECS), Intelligent systems, Decision and Control Systems (Automatic Control).
    Romm, Iliya
    Technion Israel Inst Technol, Dept Aerosp Engn, H_efa, Israel..
    Palman, Michael
    Technion Israel Inst Technol, Dept Aerosp Engn, H_efa, Israel..
    Zelazo, Daniel
    Technion Israel Inst Technol, Dept Aerosp Engn, H_efa, Israel..
    Cukurel, Beni
    Technion Israel Inst Technol, Dept Aerosp Engn, H_efa, Israel..
    Economic dispatch of a single micro gas turbine under CHP operation with uncertain demands2022In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 309, article id 118391Article in journal (Refereed)
    Abstract [en]

    This work considers the economic dispatch problem for a single micro gas turbine, governed by a discrete state- space model, under combined heat and power (CHP) operation and coupled with a utility. If the exact power and heat demands are given, existing algorithms can be used to give a quick optimal solution to the economic dispatch problem. However, in practice, the power and heat demands cannot be known deterministically, but are rather predicted, resulting in an estimate and a bound on the estimation error. We consider the case in which the power and heat demands are unknown, and present a robust optimization-based approach for scheduling the turbine's heat and power generation, in which the demand is assumed to be inside an uncertainty set. We consider two different choices of the uncertainty set relying on the l(& INFIN;)- and the l(1)-norms, each with different advantages, and consider the associated robust economic dispatch problems. We recast these as robust shortest-path problems on appropriately defined graphs. For the first choice, we provide an exact linear-time algorithm for the solution of the robust shortest-path problem, and for the second, we provide an exact quadratic-time algorithm and an approximate linear-time algorithm. The efficiency and usefulness of the algorithms are demonstrated using a detailed case study that employs real data on energy demand profiles and electricity tariffs.

  • 147. Si, Pengfei
    et al.
    Feng, Ya
    Lv, Yuexia
    Rong, Xiangyang
    Pan, Yungang
    Liu, Xichen
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    An optimization method applied to active solar energy systems for buildings in cold plateau areas - The case of Lhasa2017In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 194, p. 487-498Article in journal (Refereed)
    Abstract [en]

    Solar energy for building applications may significantly reduce the conventional energy consumption and the related carbon dioxide emissions. The comprehensive utilization of integrated solar thermal and photovoltaic systems is undoubtedly a subject of interest. In the present paper, an optimization model was proposed for integrated solar energy systems, aiming to figure out the optimal utilization and economical efficiency of solar energy resources for buildings in cold plateau areas. A case study in Lhasa city was further carried out in order to evaluate the energy and economic performance of the developed model. The results indicated that solar photovoltaic systems are preferred than solar thermal systems for typical office buildings in cold plateau areas with rich solar energy resources. In addition, a sensitivity analysis was performed to investigate the influences of financial subsidies and commercial electricity prices on the system economical performance. Furthermore, life cycle assessment was conducted to compare and analyze the performances of an optimization system and a conventional system.

  • 148.
    Sommerfeldt, Nelson
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. Michigan Technol Univ, Dept Mat Sci & Engn, Houghton, MI 49931 USA..
    Pearce, Joshua M.
    Michigan Technol Univ, Dept Mat Sci & Engn, Houghton, MI 49931 USA.;Western Univ, Ivey Business Sch, Dept Elect & Comp Engn, London, ON, England..
    Can grid-tied solar photovoltaics lead to residential heating electrification?: A techno-economic case study in the midwestern US2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 336, article id 120838Article in journal (Refereed)
    Abstract [en]

    This study aims to quantify the techno-economic potential of using solar photovoltaics (PV) to support heat pumps (HP) towards the replacement of natural gas heating in a representative North American residence from a house owner's point of view. For this purpose, simulations are performed on: (1) a residential natural gas-based heating system and grid electricity, (2) a residential natural gas-based heating system with PV to serve the electric load, (3) a residential HP system with grid electricity, and (4) a residential HP+PV system. Detailed descriptions are provided along with a comprehensive sensitivity analysis for identifying specific boundary conditions that enable lower total life cycle cost. The results show that under typical inflation conditions, the lifecycle cost of natural gas and reversable, air-source heat pumps are nearly identical, however the electricity rate structure makes PV costlier. With higher rates of inflation or lower PV capital costs, PV becomes a hedge against rising prices and encourages the adoption of HPs by also locking in both electricity and heating cost growth. The real internal rate of return for such prosumer technologies is 20x greater than a long-term certificate of deposit, which demonstrates the additional value PV and HP technologies offer prosumers over comparably secure investment vehicles while making substantive reductions in carbon emissions. Using the large volume of results generated, impacts on energy policy are discussed, including rebates, net-metering, and utility business models.

  • 149. Song, Han
    et al.
    Starfelt, Fredrik
    Daianova, Lilia
    Yan, Jinyue
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Influence of drying process on the biomass-based polygeneration system of bioethanol, power and heat2012In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 90, no 1, p. 32-37Article in journal (Refereed)
    Abstract [en]

    One of the by-products from bioethanol production using woody materials is lignin solids, which can be utilized as feedstock for combined heat and power (CHP) production. In this paper, the influence of integrating a drying process into a biomass-based polygeneration system is studied, where the exhaust flue gas is used to dry the lignin solids instead of direct condensation in the flue gas condenser (FGC). The evaporated water vapor from the lignin solids is mixed with the drying medium for consequent condensation. Thus, the exhaust flue gas after the drying still has enough humidity to produce roughly the same amount of condensation heat as direct condensation in the existing configuration. The influence of a drying process and how it interacts with the FGC in CHP production as a part of the polygeneration system is analyzed and evaluated. If a drying process is integrated with the polygeneration system, overall energy efficiency is only increased by 3.1% for CHP plant, though the power output can be increased by 5.5% compared with the simulated system using only FGC.

  • 150.
    Song, Yang
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Peskova, Monika
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Rolando, Davide
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Zucker, Gerhard
    Sustainable Thermal Energy Systems, AIT Austrian Institute of Technology, Giefinggasse 2, A-1210 Vienna, Austria.
    Madani Larijani, Hatef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration. Sustainable Thermal Energy Systems, AIT Austrian Institute of Technology, Giefinggasse 2, A-1210 Vienna, Austria.
    Estimating electric power consumption of in-situ residential heat pump systems: A data-driven approach2023In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 352, article id 121971Article in journal (Refereed)
    Abstract [en]

    International Energy Agency predicts that the global number of installed heat pumps (HP) will increase from 180 million in 2020 to approximately 600 million by 2030, covering 20% of buildings heating needs. Electric power consumption is one of the main key performance indicators for the heat pump systems from techno-economic perspective. However a common issue prevalent in many existing heat pumps is the lack of electric power measurement. The modern installations might be equipped with electric power measurement sensors but this comes at a higher system cost for the manufacturers and end-users. The primary objective of this work is to propose a virtual measurement for estimating power consumption, thereby eliminating the need for field measurement of power for heat pumps. To achieve the objective, a data-driven approach is proposed. Firstly, the in-situ data is preprocessed through data merging, cleaning, and normalization. Then, input features are pre-selected using Spearman correlation coefficients, and further refined by addressing multicollinearity problem. Following this, Extreme Gradient Boosting (XGBoost) models and polynomial models are developed by considering different features as inputs. All models are finally validated against the in-situ data from multi-units of ground source heat pump (GSHP) and air source heat pump (ASHP) installations. The results showed that the electric power consumption of GSHP can be estimated with high accuracy (99% for R2, 10 W for MAE, and 1% for MAPE) through generic data-driven models using only four easy-to-measure input features. Taking three input features as inputs for ASHP generic model, the accuracy can be reached to 83% for R2, 125 W for MAE, and 9% for MAPE. The method presented in this paper can be applied to estimate power consumption of millions of heat pumps and consequently add a significant value as well as provide different types of services, such as cost-saving benefits for manufacturers and end-users, flexibility services for aggregators and electricity grids.

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