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  • 1.
    Ackermann, Thomas
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Historical Development and Current Status of Wind Power2012In: Wind Power in Power Systems, Second Edition, John Wiley & Sons, 2012, p. 21-24Chapter in book (Refereed)
    Abstract [en]

    The chapter provides an overview of the historical development (mechanical and electrical power generation) of wind power. It also present the current status of wind power world-wide (capacity installed) together with a discussion of the main drivers for the wind power development, e.g. feed-in tariffs, green certificates etc. Furthermore, the chapter briefly discuss the current trends in wind turbine technology, e.g. larger turbines, and projects development, e.g. offshore wind power.

  • 2.
    Ackermann, Thomas
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Wind Power in Power Systems2005Book (Other academic)
    Abstract [en]

    As environmental concerns have focussed attention on the generation of electricity from clean and renewable sources, wind energy has become the world's fastest growing energy source. The authors draw on substantial practical experience to address the technical, economic and safety issues inherent in the exploitation of wind power in a competitive electricity market. Presenting the reader with all the relevant background information key to understanding the integration of wind power into the power systems, this leading edge text: Presents an international perspective on integrating a high penetration of wind power into the power system Offers broad coverage ranging from basic network interconnection issues to industry deregulation and future concepts for wind turbines and power systems Discusses wind turbine technology, industry standards and regulations along with power quality issues Considers future concepts to increase the penetration of wind power in power systems Presents models for simulating wind turbines in power systems Outlines current research activities Essential reading for power engineers, wind turbine designers, wind project development and wind energy consultants dealing with the integration of wind power systems into distribution and transmission networks, this text would also be of interest to network engineers working for power utility companies dealing with interconnection issues and graduate students and researchers in the field of wind power and power systems.

  • 3.
    Ackermann, Thomas
    KTH.
    Wind Power in Power Systems, Second Edition2012Collection (editor) (Refereed)
    Abstract [en]

    The second edition of the highly acclaimed Wind Power in Power Systems has been thoroughly revised and expanded to reflect the latest challenges associated with increasing wind power penetration levels. Since its first release, practical experiences with high wind power penetration levels have significantly increased. This book presents an overview of the lessons learned in integrating wind power into power systems and provides an outlook of the relevant issues and solutions to allow even higher wind power penetration levels. This includes the development of standard wind turbine simulation models. This extensive update has 23 brand new chapters in cutting-edge areas including offshore wind farms and storage options, performance validation and certification for grid codes, and the provision of reactive power and voltage control from wind power plants. Key features: Offers an international perspective on integrating a high penetration of wind power into the power system, from basic network interconnection to industry deregulation; Outlines the methodology and results of European and North American large-scale grid integration studies; Extensive practical experience from wind power and power system experts and transmission systems operators in Germany, Denmark, Spain, UK, Ireland, USA, China and New Zealand; Presents various wind turbine designs from the electrical perspective and models for their simulation, and discusses industry standards and world-wide grid codes, along with power quality issues; Considers concepts to increase penetration of wind power in power systems, from wind turbine, power plant and power system redesign to smart grid and storage solutions. Carefully edited for a highly coherent structure, this work remains an essential reference for power system engineers, transmission and distribution network operator and planner, wind turbine designers, wind project developers and wind energy consultants dealing with the integration of wind power into the distribution or transmission network. Up-to-date and comprehensive, it is also useful for graduate students, researchers, regulation authorities, and policy makers who work in the area of wind power and need to understand the relevant power system integration issues.

  • 4.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Holttinen, H.
    Overview of Integration Studies - Methodologies and Results2012In: Wind Power in Power Systems, Second Edition, John Wiley & Sons, 2012, 2, p. 361-386Chapter in book (Refereed)
  • 5.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems. Energynautics GmbH, Germany; Technical University in Darmstadt (TUD), Germany.
    Morthorst, P. E.
    Economic Aspects of Wind Power in Power Systems2005In: Wind Power in Power Systems, John Wiley & Sons, 2005, p. 383-410Chapter in book (Other academic)
  • 6.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Orths, A.
    Rudion, K.
    Transmission Systems for Offshore Wind Power Plants and Operation Planning Strategies for Offshore Power Systems2012In: Wind Power in Power Systems, John Wiley & Sons, 2012, 2, p. 293-327Chapter in book (Refereed)
    Abstract [en]

    The electric system within an offshore wind power plant and its connection to the main power system pose new challenges to the experts. The best way of interconnecting the wind turbines inside a wind farm has to be found, fulfilling both, redundancy requirements without compromising economic feasibility. The best choice between technologies (HVAC, HVDC - VSC or LCC) for connecting windfarms to shore has to be made, depending on several criteria. The risk of losing this connection versus redundancy has to be economically evaluated. By combining interconnectors and offshore windfarm connections in a modular way, a DC offshore grid can be developed. Anyhow, already during the planning phase the secure operation should be considered thoroughly, because the optimal architecture has to be found, minimizing the necessary assets ensuring secure operation and facilitating later expansion options. The interaction with the onshore grid has to be investigated as well. To enable investigations covering these issues a benchmark offshore test system has been developed which is described in this chapter.

  • 7.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    The Value of Wind Power2012In: Wind Power in Power Systems, John Wiley & Sons, 2012, 2, p. 131-155Chapter in book (Refereed)
    Abstract [en]

    The aim of the power plants in a power system is to supply the load in an economical, reliable and environmentally acceptable way. Different power plants can fulfil these requirements in different ways. In order to select the right sources it is important to compare the value of the different sources using an objective approach. The aim of this chapter is describe the different needs of a power system and how these needs can be met with wind power, that is, the value of wind power in a certain system. The values are operating cost value, capacity value, control value, grid loss reduction value and grid investment value. The values can be calculated for different types of power plants, they can be both positive and negative, and they can be calculated both as a physical cost value and a market value.

  • 8.
    Ackermann, Thomas
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Tröster, E.
    New Control Concept for Offshore Wind Power Plants: Constant-Speed Turbines on a Grid with Variable Frequency2012In: Wind Power in Power Systems, John Wiley & Sons, 2012, 2, p. 345-359Chapter in book (Refereed)
    Abstract [en]

    By using a permanent magnet induction machine as wind generator, the gearbox and converter can be omitted, and the total number of parts reduced leading to a low maintenance and reliable turbine for offshore application. The rotation speed of the turbine however cannot be matched to the wind speed, reducing the energy yield at part load. To overcome this drawback, a central converter can be used, which adjusts the frequency of the local grid in the wind park; this is the so-called park-variable concept. This concept has been compared with respect to energy yield with constant speed and variable speed turbines. Overall, the differences in energy yield of the investigated concepts are so small that other criteria, such as reliability or cost, may be relevant for the selection of one or the other approach. Above all, the park-variable concept represents an interesting alternative to today's common concepts.

  • 9.
    Acuña, José
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Distributed thermal response tests: New insights on U-pipe and Coaxial heat exchangers in groundwater-filled boreholes2013Doctoral thesis, comprehensive summary (Other academic)
    Abstract [en]

    U-pipe Borehole Heat Exchangers (BHE) are widely used today in ground source heating and cooling systems in spite of their less than optimal performance. This thesis provides a better understanding on the function of U-pipe BHEs and Investigates alternative methods to reduce the temperature difference between the circulating fluid and the borehole wall, including one thermosyphon and three different types of coaxial BHEs.

    Field tests are performed using distributed temperature measurements along U-pipe and coaxial heat exchangers installed in groundwater filled boreholes. The measurements are carried out during heat injection thermal response tests and during short heat extraction periods using heat pumps. Temperatures are measured inside the secondary fluid path, in the groundwater, and at the borehole wall. These type of temperature measurements were until now missing.

    A new method for testing borehole heat exchangers, Distributed Thermal Response Test (DTRT), has been proposed and demonstrated in U-pipe, pipe-in-pipe, and multi-pipe BHE designs. The method allows the quantification of the BHE performance at a local level.

    The operation of a U-pipe thermosyphon BHE consisting of an insulated down-comer and a larger riser pipe using CO2 as a secondary fluid has been demonstrated in a groundwater filled borehole, 70 m deep. It was found that the CO2 may be sub-cooled at the bottom and that it flows upwards through the riser in liquid state until about 30 m depth, where it starts to evaporate.

    Various power levels and different volumetric flow rates have been imposed to the tested BHEs and used to calculate local ground thermal conductivities and thermal resistances. The local ground thermal conductivities, preferably evaluated at thermal recovery conditions during DTRTs, were found to vary with depth. Local and effective borehole thermal resistances in most heat exchangers have been calculated, and their differences have been discussed in an effort to suggest better methods for interpretation of data from field tests.

    Large thermal shunt flow between down- and up-going flow channels was identified in all heat exchanger types, particularly at low volumetric flow rates, except in a multi-pipe BHE having an insulated central pipe where the thermal contact between down- and up-coming fluid was almost eliminated.

    At relatively high volumetric flow rates, U-pipe BHEs show a nearly even distribution of the heat transfer between the ground and the secondary fluid along the depth. The same applies to all coaxial BHEs as long as the flow travels downwards through the central pipe. In the opposite flow direction, an uneven power distribution was measured in multi-chamber and multi-pipe BHEs.

    Pipe-in-pipe and multi-pipe coaxial heat exchangers show significantly lower local borehole resistances than U-pipes, ranging in average between 0.015 and 0.040 Km/W. These heat exchangers can significantly decrease the temperature difference between the secondary fluid and the ground and may allow the use of plain water as secondary fluid, an alternative to typical antifreeze aqueous solutions. The latter was demonstrated in a pipe-in-pipe BHE having an effective resistance of about 0.030 Km/W.

    Forced convection in the groundwater achieved by injecting nitrogen bubbles was found to reduce the local thermal resistance in U-pipe BHEs by about 30% during heat injection conditions. The temperatures inside the groundwater are homogenized while injecting the N2, and no radial temperature gradients are then identified. The fluid to groundwater thermal resistance during forced convection was measured to be 0.036 Km/W. This resistance varied between this value and 0.072 Km/W during natural convection conditions in the groundwater, being highest during heat pump operation at temperatures close to the water density maximum.

  • 10.
    Acuña, José
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Palm, Björn
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Distributed thermal response tests on pipe-in-pipe borehole heat exchangers2013In: Applied Energy, ISSN 0306-2619, E-ISSN 1872-9118, Vol. 109, no SI, p. 312-320Article in journal (Refereed)
    Abstract [en]

    Borehole Thermal Energy Storage systems typically use U-pipe Borehole Heat Exchangers (BHE) having borehole thermal resistances of at least 0.06 K m/W. Obviously, there is room for improvement in the U-pipe design to decrease these values. Additionally, there is a need for methods of getting more detailed knowledge about the performance of BHEs. Performing Distributed Thermal Response Tests (DTRT) on new proposed designs helps to fill this gap, as the ground thermal conductivity and thermal resistances in a BHE can be determined at many instances in the borehole thanks to distributed temperature measurements along the depth. In this paper, results from three heat injection DTRTs carried out on two coaxial pipe-in-pipe BHEs at different flow rates are presented for the first time. The tested pipe-in-pipe geometry consists of a central tube inserted into a larger external flexible pipe, forming an annular space between them. The external pipe is pressed to the borehole wall by applying a slight overpressure at the inside, resulting in good thermal contact and at the same time opening up for a novel method for measuring the borehole wall temperature in situ, by squeezing a fiber optic cable between the external pipe and the borehole wall. A reflection about how to calculate borehole thermal resistance in pipe-in-pipe BHEs is presented. Detailed fluid and borehole wall temperatures along the depth during the whole duration of the DTRTs allowed to calculate local and effective borehole thermal resistances and ground thermal conductivities. Local thermal resistances were found to be almost negligible as compared to U-pipe BHEs, and the effective borehole resistance equal to about 0.03 K m/W. The injected power was found to be almost evenly distributed along the depth.

  • 11.
    Aga, Aboma Emiru
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Fuel Supply Investigation for an Externally Fired Microturbine based Micro CHP System: Case study on a selected site in Bishoftu, Ethiopia2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Sudden change on earth’s climate, which is a result of an increase in CO2 in the atmosphere, is mainlycaused by burning of fossil fuels for various energy services. However, for the energy services to befavourable to the environment, there should be a balance with the environmental protection, and we cancall that “Sustainable Innovative Development”.

    “EXPLORE Polygeneration” initiative will serve as an important tool to promote the application ofrenewable technologies extending to the future sustainable energy engineering field. This paper is intendedin investigating a suitable fuel supply for the microturbine based micro CHP system available at theDivision of Heat and Power Technology, KTH, Sweden; for a site called “Alema Farm PLC”, Bishoftu,Ethiopia.

    Though there is a large biomass energy resource and a huge potential to produce hydroelectric power inEthiopia, the modern energy sector is very small and the energy system is mainly characterized by biomassfuel supplies and household energy consumption. The nation’s limited biomass energy resource is believedto have been depleting at an increasingly faster rate.

    Of the many and surplus amount of renewable energy resources available in and around Alema FarmPLC, poultry litter and pig’s manure are selected to be the two main energy sources for the CHP systemavailable in the lab, after passing through different conversion techniques. However, after consideringsome basic properties like: Energy content and Bulk Density of the fuel, Moisture content , Ashcharacteristic, Tar content, Fuel logistics, Local storage, Fuel feeder system, and Magnitude of GHGReduction; poultry litter is found to be the most convenient to produce a syngas with a Downdraftatmospheric gasifier available in the HPT lab.

    Finally, For the problems caused by the nature of the poultry litter by itself and the methods used in theconversion process, the 40 TRIZ principles of TRIZ inventive principles is used and some major pointsare recommended.

  • 12.
    Ahl, Amanda
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Eklund, Johanna
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Lundqvist, Per
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Yarime, M.
    Balancing formal and informal success factors perceived by supply chain stakeholders: A study of woody biomass energy systems in Japan2018In: Journal of Cleaner Production, ISSN 0959-6526, E-ISSN 1879-1786, Vol. 175, p. 50-59Article in journal (Refereed)
    Abstract [en]

    Small-scale woody biomass energy systems have an inherent ability to aid in emissions reduction while stimulating local economies and, as collective energy systems, are strongly connected to supply chain design based on local conditions and stakeholder integration. Despite an abundance of forest area alongside the promotion of biomass in energy policies, however, woody biomass utilization still remains low in Japan. The woody biomass supply chain, considered as a socio-technical system, involves a complex, cross-sectoral stakeholder network in which inter-organizational dynamics necessitates well-organized management based on an understanding of formal factors such as technology, as well as informal factors such as social relations and culture. In this paper, success factor perceptions from across the woody biomass supply chain are investigated based on semi-structured interviews with four stakeholders in the Kyushu region of Japan. Identified success factors here are: 1) respect of values & traditions, 2) transportation infrastructure, 3) business model integration, 4) relationship & trust, 5) local vitalization and 6) biomass quality control. A convergence as well as divergence of perceptions are observed, involving both formal and informal dimensions. Aiming to balance perceptions and to enable long-term success of woody biomass in Japan, a series of policy implications are drawn, including cross-ministerial integration, knowledge building on wood logistics, forest certification, local coordinators, biomass quality control standards and a feed-in-tariff for heat. This paper suggests a new arena of policy-making based on the importance of considering both informal and formal dimensions in energy policy.

  • 13.
    Ahmed, Amber
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Gong, Jindan
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Assessment of the Electricity Generation Mix in Ghana: the Potential of Renewable Energy2017Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Electricity is a fundamental part a functioning society. Ghana’s electricity system is strained by an ever-growing climate instability and increase of population. Therefore, it is crucial for the country's development that it's electricity supply is done in a sustainable way.

    This report aims to analyze Ghana’s ability to reach SDG 7.1 and the Marrakech Vision, an outcome from the COP 22 meeting in Morocco. This was done by creating a model over Ghana’s electricity system and how it develops over time, called BAU, using the analytical tools: OSeMOSYS and OnSSET. A practical implementation of BAU was then discussed. After that, three development scenarios with different renewable energy targets for the electricity system, were implemented in the model. The results show that CSP and natural gas power plants were the most prominent electricity producers. The growing share of renewable energy in the target scenarios was mostly due to wind power, replacing the natural gas power plants.

    Ghana has local natural gas resources as well as high solar potential. The rising share of renewable energy limits the fossil fuel emission. At the same time, this increased share also endangers the reliability of the electricity supply, as the capacity of renewable energy resources fluctuate and could lead to high investment costs. BAU can be a possible solution which minimizes the fossil fuel consumption and limits the CO2 emissions, but at the risk of possibly having an unreliable electricity supply. To be able to meet SDG 7.1, increasing the share of renewable energy in electricity generation can be a solution, but at the same time, not all requirements of the goal will be fulfilled.

  • 14.
    Aid, Graham
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Potential technology for the advanced utilization of construction, demolition, and industrial waste2008Conference paper (Refereed)
  • 15.
    Alahakoon, Sanath
    et al.
    Central Queensland University, Australia.
    Leksell, Mats
    KTH, School of Electrical Engineering (EES), Electric power and energy systems.
    Emerging energy storage solutions for transportation - A review: An insight into road, rail, sea and air transportation applications2015In: Electrical Systems for Aircraft, Railway and Ship Propulsion, ESARS, IEEE , 2015Conference paper (Refereed)
    Abstract [en]

    Increasing usage of hybrid electric vehicles, plug-in electric vehicles and emerging new concepts in transportation such as electric highways have raised the significant role of energy storage solutions for transportation to its highest level. It is impossible to specify a single energy storage solution that can satisfactorily fulfill the varying performance demands of various applications in transportation. This paper will identify some of the most demanded performance requirements from some of the key applications in transportation and assess the suitability of emerging energy storage solutions against those.

  • 16.
    Albrecht, Martin
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms).
    Enabling socio-technical transitions – electric vehicles and high voltage electricity grids as focal points of low emission futures2017Licentiate thesis, comprehensive summary (Other academic)
    Abstract [en]

    Today humankind is facing numerous sustainability challenges that require us to question CO2 intensive practices like those present in the transport and energy sector. To meet those challenges, many countries have adopted ambitious climate targets. Achieving such targets requires an understanding of the wider socio-technical context of transitions. The aim of this licentiate thesis is therefore to analyse such socio-technical transitions towards low-emission futures enabled by the electrification of passenger cars and high voltage grid development.

    A combination of different transitions theories (for ex. Multi-level perspective and Technological innovation systems) and institutional theory has been used. To reach the aim paper I analyses the climate impacts of electric vehicles (EVs) and policy measures to achieve a breakthrough scenario for EVs. The results show that a mixture of short and long term policies are needed that take into account the technology development stage and behavioural aspects of EV adopters. Paper II addresses the need to include the high voltage transmission grid and its planning procedures as a central part of debates on transitions. Therefore the opportunities, challenges and reasons for conflict in the established regime are studied. The results show that in order to achieve a sustainable grid development regime, it is necessary to spend time on achieving legitimacy and social sustainability. The third paper uses semi-structured expert interviews and focuses on innovation dynamics for EV adoption. By focusing on dynamics instead of single policy measures, it is possible to grasp interactions within a niche, but also in between a niche, regime and landscape. The results show that strong initial technology legitimacy was needed to start substantial innovation dynamics. This could be further strengthened with a strong and broad coalition of actors. Both those factors led, if present, to an improved variety and match of policy instruments.

    As such this thesis has shown that transitions are not just about technology or policy instruments as such but about the dynamics and processes needed to enable them. This can be relevant in other transitions that otherwise may underestimate the importance of these components.

  • 17.
    Albrecht, Martin
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms).
    Nordic power road map 2050: Strategic choices towards carbon neutrality. D4.1.R Institutional grid review.2013Report (Other academic)
  • 18.
    Albrecht, Martin
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Environmental Strategies Research (fms).
    System innovation dynamics around electric vehicles. The cases of Norway, Denmark and Sweden.Manuscript (preprint) (Other academic)
    Abstract [en]

    This paper focuses on the comparison of electric car innovation patterns in Norway, Sweden and Denmark. Doing so, it takes a closer look at what the most essential dynamics in the systems were over time and what enabled those dynamics. The main research aim is to contribute to a wider understanding of why Norway is so much ahead of Sweden and Denmark in electric car adoption. The purpose is also to adopt a perspective that goes beyond a mere focus on economic policy instruments. In order to do so different theory elements are combined in a framework. These elements stem from the transition theory literature field, especially the technological innovation system (TIS) and the multi-level perspective (MLP). This combination allows analysing the development behind a dynamic, not just when it comes to an innovation itself but also with regards to the established regime. The data is gathered through analysis of existing documents and data as well as a series of 27 expert interviews conducted in the three case countries. The findings suggest that there are important differences in transition patterns that can account for the electric vehicle (EV) diffusion situation we can find nowadays in the three Nordic countries. An important stepping stone was the need for a very strong legitimacy of the original EV vision that is also anchored in a coordinated, sector overarching coalition of actors that thinks strategically and long term. Moreover some general beneficial dynamics could be identified across the countries in question. In Norway these beneficial dynamics can be summarised as a systems motor, in Denmark as a failed entrepreneurial motor that shifted towards a constrained municipal motor and in Sweden as a loosely, coordinated and weaker version of a systems motor.

  • 19.
    Alessandro, Magny
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Pdungsilp, Aumnad
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Martinac, Ivo
    KTH, School of Architecture and the Built Environment (ABE), Civil and Architectural Engineering, Building Service and Energy Systems.
    Optimization of Energy Supply Systems for a Sustainable District in Stockholm Using Genetic Algorithms2014In: Proceedings of the World Sustainable Buildings Conference 2014, 2014Conference paper (Refereed)
  • 20.
    Alfredsson, Bo
    et al.
    KTH, School of Engineering Sciences (SCI), Solid Mechanics (Dept.). STandUP Wind.
    Segalini, Antonio
    KTH, School of Engineering Sciences (SCI), Mechanics, Fluid Physics. STandUP Wind.
    Wind farms in complex terrains: an introduction2017In: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 375, no 2091Article in journal (Refereed)
    Abstract [en]

    Wind energy is one of the fastest growing sources of sustainable energy production. As more wind turbines are coming into operation, the best locations are already becoming occupied by turbines, and wind-farm developers have to look for new and still available areas-locations that may not be ideal such as complex terrain landscapes. In these locations, turbulence and wind shear are higher, and in general wind conditions are harder to predict. Also, the modelling of the wakes behind the turbines is more complicated, which makes energy-yield estimates more uncertain than under ideal conditions. This theme issue includes 10 research papers devoted to various fluid-mechanics aspects of using wind energy in complex terrains and illustrates recent progress and future developments in this important field. This article is part of the themed issue 'Wind energy in complex terrains'.

  • 21.
    Almulla, Youssef
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Gulf Cooperation Council (GCC) countries 2040 energy scenario for electricity generation and water desalination.2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Judicious modeling of an energy system can help provide insights as to how elements of the energy system might be configured in the longer term. The current and future electricity and water desalination systems of each GCC country were represented using a full-cost based optimization tool called MESSAGE and the following scenarios were examined:

    1. The business as usual scenario (BAU): current energy system is extended into the future without any changes. The energy system structure and characteristics are kept the same. The fuel prices are also kept at the current subsidized levels.

    2 - The netback-pricing scenario: all fuel costs are increased to the international market price. The freed amount of fuel is assumed to be available for export to the international market. Moreover, this scenario examines different carbon tax options of 0, 20,30 ,40 and 50 dollars per kilo tons of CO2 emissions.

    3 - The Nuclear hub scenario: examines the idea of a “nuclear hub” state for the GCC region that can have all the “know-how” and logistics to provide sufficient nuclear energy for the GCC through the Interconnection Grid “GCCIG”.

    Results shows that fossil fuels will continue to play an important role in a least cost future for the region. This is due, in no small part, to the cheap natural gas resources in the GCC. Despite the high renewable energy technologies potential, their penetration – given the study assumptions - proved to be important, but limited in the GCC. On the other hand, nuclear energy shows clear economic potential. 

  • 22. AlSkaif, T.
    et al.
    Zapata, M. G.
    Bellalta, B.
    Nilsson, Anders
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering.
    A distributed power sharing framework among households in microgrids: a repeated game approach2016In: Computing, ISSN 0010-485X, E-ISSN 1436-5057, p. 1-15Article in journal (Refereed)
    Abstract [en]

    In microgrids, the integration of distributed energy resources (DERs) in the residential sector can improve power reliability, and potentially reduce power demands and carbon emissions. Improving the utilization of renewable energy in households is a critical challenge for DERs. In this regard, renewable power sharing is one of the possible solutions to tackle this problem. Even though this solution has attracted significant attention recently, most of the proposed power sharing frameworks focus more on centralized schemes. In contrast, in this paper, the performance of a proposed distributed power sharing framework is investigated. The problem is formulated as a repeated game between households in a microgrid. In this game, each household decides to cooperate and borrow/lend some amount of renewable power from/to a neighboring household, or to defect and purchase the entire demands from the main grid based on a payoff function. The Nash equilibrium of this game is characterized and the effect of the strategies taken by the households on the system is analyzed. We conduct an extensive evaluation using real demand data from 12 households of different sizes and power consumption profiles in Stockholm. Numerical results indicate that cooperation is beneficial from both an economical and environmental perspective and that households can achieve cost savings up to 20 %.

  • 23.
    Alvehag, Karin
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Söder, Lennart
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Quality regulation impact on investment decisions in distribution system reliability2012In: 9th International Conference on the European Energy Market, EEM 12, IEEE , 2012, p. 6254646-Conference paper (Refereed)
    Abstract [en]

    Performance-based regulations accompanied by quality regulations are gaining ground. Quality regulations imply new financial risks for the distribution system operator (DSO). In fact, the development of the regulatory model has been identified as a key factor in operations planning for a DSO. Lifetimes of distribution system components are very long and how the quality regulation might develop in the future is unknown. This paper develops a method - the regulation impact method - that can be used to investigate how changes in the quality regulation parameters affect the economic performance of an investment strategy. The proposed regulation impact method is based on net present value calculations of the total reliability cost. The new method is applied to the current Swedish quality regulation in a case study. In the case study, possible future parameter changes and their effect on the DSO's financial risk when adopting different investment strategies are investigated. With the new method it is possible to analyze how robust an investment strategy is to changes in quality regulation design.

  • 24.
    Amelin, Mikael
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    An Evaluation of Intraday Trading and Demand Response for a Predominantly Hydro-Wind System Under Nordic Market Rules2015In: IEEE Transactions on Power Systems, ISSN 0885-8950, E-ISSN 1558-0679, Vol. 30, no 1, p. 3-12Article in journal (Refereed)
    Abstract [en]

    Many countries are planning for a large-scale expansion of wind power. This development will have a significant impact on power system operation and economics. One of the challenges is that the difficulty to forecast wind power generation will increase the need for real-time balancing. This paper presents a study of how the impact of wind power forecast errors can be reduced by changes in the market design. The study is based on the conditions in the Nordic electricity market. A characteristic of this market is that there is a large share of flexible hydro generation; hence, ramp and unit commitment constraints rarely constrain dispatch. The need for regulation during real-time is provided in a voluntary real-time balancing market, where players can be compensated for their redispatch costs. Case studies are presented which show that a shift from day-ahead to intraday trading and increased demand response can improve the performance when the share of wind power is increasing.

  • 25. Ammenberg, J.
    et al.
    Anderberg, S.
    Lönnqvist, Tomas
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Grönkvist, Stefan
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Energy Processes.
    Sandberg, Thomas
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.).
    Biogas in the transport sector—actor and policy analysis focusing on the demand side in the Stockholm region2018In: Resources, Conservation and Recycling, ISSN 0921-3449, E-ISSN 1879-0658, Vol. 129, p. 70-80Article in journal (Refereed)
    Abstract [en]

    Sweden has ambitions to phase out fossil fuels and significantly increase the share of biofuels it uses. This article focuses on Stockholm County and biogas, with the aim to increase the knowledge about regional preconditions. Biogas-related actors have been interviewed, focusing on the demand side. Biogas solutions play an essential role, especially regarding bus transports and taxis. Long-term development has created well-functioning socio-technical systems involving collaboration. However, uncertainties about demand and policy cause hesitation and signs of stagnating development. Public organizations are key actors regarding renewables. For example, Stockholm Public Transport procures biogas matching the production at municipal wastewater treatment plants, the state-owned company Swedavia steers via a queuing system for taxis, and the municipalities have shifted to “environmental cars”. There is a large interest in electric vehicles, which is expected to increase significantly, partially due to suggested national policy support. The future role of biogas will be affected by how such an expansion comes about. There might be a risk of electricity replacing biogas, making it more challenging to reach a fossil-free vehicle fleet. Policy issues strongly influence the development. The environmental car definition is of importance, but its limited focus fails to account for several different types of relevant effects. The dynamic policy landscape with uncertainties about decision makers’ views on biogas seems to be one important reason behind the decreased pace of development. A national, long-term strategy is missing. Both the European Union and Sweden have high ambitions regarding a bio-based and circular economy, which should favor biogas solutions.

  • 26.
    Ancel, Julie
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Improvement of the electrical part of Idénergie's hydrokinetic turbine2014Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Idénergie develops the first domestic hydrokinetic turbine for rivers. Itaims at producing about 100W in a 1.4m/s river to power up remote locations.Idénergie’s turbine has two main advantages: a completely watertight shaftlessgenerator and an integrated smart converter. The first turbines are planned tobe sold in June 2014.To be able to test the embedded intelligence in the lab, Idénergie’s testbench must be able to reproduce river conditions. Measurements have beenperformed in a river and provide the torque developed by the river at differentspeeds. On the test bench controlled by a LabView program, the rotationalspeed is measured and the corresponding torque computed. This torque is setas the new command and makes the test bench behave as if it was driven by aturbine in a river.Idénergie’s generator contains a rotor made of permanent magnets.These magnets are provided by a supplier and their quality needs to bechecked. For this purpose, a magnetometer is designed and built. It contains 5Hall effect sensors which move at a constant speed above a magnet andmeasure its magnetic field. The magnetometer is able to compare magnets to areference and to detect the faulty ones. The sensors are also used to measurethe magnetic field of the rotor and show that the custom-made shape of themagnets has no influence on the sinusoidal field.The converter transforms the three-phase current to direct current andcontrols the rotational speed. This is done thanks to an embedded electroniccard, which is about to be working properly. The Maximum Power PointTracking algorithm ensures that the rotational speed is optimum in order toproduce the maximum power output. The code loaded on this card is written inits main part but needs to be tested on the test bench once the card will beoperational.

  • 27.
    Andersson, Carl
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Olausson, Linus
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Identifiering av mervärden i EPC-projekt2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    In this report a study is carried out with the aim to identify added values of EPC projects implemented in schools in order to increase the interest of EPC projects on the market. The report examines how the planned maintenance, supervision, maintenance and corrective maintenance is affected, how insurance premiums and terms are affected, the indoor environment and how the tasks of the operating staff is changing. A literature study of energy savings, energy use in schools, maintenance and insurance as well as how energy efficiency improvements are related to the Swedish environmental objectives has been made. Visits were carried out in Ludvika, interviews were also carried out with operation technicians and local strategists in Ludvika as well as employees of insurance companies.

    Schools often have neglected maintenance and problems with ventilation and indoor environment. Schools also have a large energy saving potential due to their low utilization, mainly because they are empty parts of the year. All Swedish schools could reduce their electricity consumption by 1 TWh per year, which in money equivalents to the salary costs of about 2,000 teaching positions.

    8 schools in Ludvika and 10 schools in Piteå who has completed EPC projects have been studied. The time periods studied are seven years for Ludvika, 2006 – 2012, and for Piteå five years, 2010 – 2014. The data of fault reports and maintenance costs are taken from the municipalities, and descriptions of schools and EPC projects have been received from Caverion who has carried out the EPC projects. Data for maintenance has to some extent been selected in consultation with employees at the municipalities.

    The number of error reports in Piteå schools have shown a slight downward trend with a peak while the EPC project was carried out and one year after. Ludvika has shown an upward trend in maintenance costs, but this is probably due to previously accumulated maintenance. The amount of corrective maintenance is reduced, but only after the project when newly found errors have been fixed and the systems have been properly adjusted. The tasks related to supervisory and maintenance has changed when remote control of systems was installed which leads to a better overview and simplifies troubleshooting. The indoor temperature got more stable, but only after they fixed the weaknesses revealed in connection with the operational optimization. However, there are complaints in Ludvika of low temperatures, but it is caused the target temperature being set too low by the municipality. Insurance is only marginally affected, and only when damage prevention measures are implemented in the properties, which is not done in the studied properties. However, the underlying data sets are too small and over a too small time period to prove any certain changes.

    An added value identified is the ability to use EPC projects as a tool to address deferred maintenance in the real estate portfolio outside the normal budgetary framework while achieving energy savings. 

  • 28.
    Andersson, Elin
    KTH, School of Industrial Engineering and Management (ITM), Industrial Ecology.
    Use cases and Business Models: Urban Smart Grid2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The EU has established a climate and energy package that includes solutions of the threatening climate changes and is called the 202020 package. The goal is to reduce the greenhouse gases with 20 % until the year 2020. The energy use should be lowered with20 % and the energy efficiency will be 20% higher.

    On account of this, Stockholm city is developing a new city district which is called Stockholm Royal Seaport. The vision of Stockholm Royal Seaport is to develop a sustainable city district that should contribute to innovation, development and promotion of the Swedish environmental technology. Through a new and more efficient grid, Smart Grid, the total energy usage will be lowered, the load optimized and it will be possible to connect decentralized electricity recourses as well as integrate electric vehicles. To make the Smart Grid implementation as good as possible use cases have been a big part of the preparatory work. A use case is a document consisting of one or several scenarios that describe how actors, who could be a human or a piece of hardware, interact with the system to reach a specific goal.

    This master thesis has been performed at and assigned by Fortum. The aim of the study was to deliver ideas and suggestions for new markets and business models and create new incitements, which will be needed to succeed with the implementation of Smart Grid; this will be done especially with regards to sustainable development. During the project around 170 existing use cases were organised depending on which area in the grid they belonged to. This was done so that an area in Stockholm Royal Seaport could be picked out to be deeper analysed. The use cases concerning the integration and use of the electric vehicle went through a closer study to evaluate what changes are needed in management, regulation etc., in order to success with the development of the new grid. The "new" aim of this study became to show the differences in how much carbon dioxide the electric vehicle emits and how much its owner pays in taxes compared to a regular vehicle. The two vehicles that have been compared are both from Renault. The emissions from the electric vehicle are considerate to be equal to the emission from production of the used electricity. The emissions have been calculated using historical electricity production data together with a production forecast of the year of 2020. The outcome of the calculations differs depending on if the vehicle "uses" the total production mix or the electricity produced on the margin. The results show that the electric vehicle pays a third less in taxes: if one looks at the total costs for the vehicles, the investment of the electric vehicle has a payback time of ten years. Substitute a conventional vehicle for the electric vehicle reduces the carbon dioxide emissions between 0,54 and 1,67 ton a year. This indicates that a differentiated carbon dioxide tax would be favouring the electric vehicle and also makes one pay for what one emits.

  • 29.
    Andersson, Niklas
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Malmös strategi för social hållbarhet med fokus på förorten2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report covers the social sustainability agenda in the suburbs Rosengård and Kroksbäck, situated in Malmö. These suburbs where constructed mainly in the years 1960-1975 and are now in need of refurbishing. There is also a housing shortage in Malmö and the demand is mainly for inexpensive apartments. Young adults, students, immigrants, senior citizens and families alike are looking for places where they can afford to live. The high demand for living space and the need of renovation could spark a gentrification process which would not be socially sustainable. The main actors whose social sustainability agendas are reviewed are the municipality of Malmö and the municipal owned housing company of MKB as well as the tenants’ association. The report also covers how the dialogue between the residents in Rosengård, the civil servants of the city and the landlords is carried out. Reactions from the residents in Rosengård have been researched in newspapers, but it proved hard to find while criminal reports where abundant. Lastly two examples on how the social sustainability agenda have been carried out in Gothenburg is presented. The methodology which the results are based on is a literature review.

    The report finds that both Malmö and Gothenburg are using a matrix formed decision tool in order to incorporate social aspects in all planning decisions. This is something which works well in both cities. The municipality of Malmö took a decision in 2014 that the social justice will increase when building new apartments. They do however realize the most of the newly constructed homes might be too expensive but they hope that this will eventually free up cheaper apartments. Different investment programs have been initiated in Rosengård, Rosengård I förvandling is one of them. Part of this program was based on local farming and different pedagogical activities. MKB are using social clauses when hiring different contractors, they stipulate that ten percent of the workforce should be locals or people who previously have been unemployed. This would be one the few tangible solutions which MKB is contributing with to solving the problem with lack of social sustainability. The tenants’ association is mainly focusing on minimizing the rent increase. They do however see a potential in so called neighborhood effects such as social learning were tenants are affecting other tenants in a positive way. The tennants’ association believes, as do the municipality of Malmö, that this can be achieved partly by constructing new houses among the older ones.

    The dialogue between the residents and the municipality used to be characterized as too little too late in the planning process. The revised aim with the dialogue is now to bring the citizens opinions into the decision process at an earlier stage. A potential problem could be the language barriers as there are many immigrants living in suburban Malmö. However in projects where the dialogue where given a priority the outcome became a success and the decision enjoys a broad support. As a recommendation for future research, a survey or deep interviews with the residents on their thoughts about actions taken to increase the social sustainability could be carried out. This is something which this report is lacking, good feedback from the residents. 

  • 30. Angioni, A.
    et al.
    Hooshyar, Hossein
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Vanfretti, Luigi
    KTH, School of Electrical Engineering (EES), Electric Power and Energy Systems.
    Garcia, C.C.
    et al.,
    A distributed automation architecture for distribution networks, from design to implementation2017In: Sustainable Energy, Grids and Networks, ISSN 0284-4354, E-ISSN 2352-4677Article in journal (Refereed)
    Abstract [en]

    With the current increase of distributed generation in distribution networks, line congestions and PQ issues are expected to increase. The smart grid may effectively coordinate DER, only when supported by a comprehensive architecture for automation. In IDE4L project such architecture is designed based on monitoring, control and business use cases. The IDE4L instance of SGAM architecture is derived and explained in details. The automation actor are specified in terms of interfaces, database and functions. The division in these three layers boosted the implementation phase as dedicated interfaces, databases or application has been developed in a modular way and can be installed in different HW/SW. Some implementation instances are presented and the main output of the architecture is discussed with regards to some indexes as communication traffic and level of distribution of automation functions.

    The full text will be freely available from 2019-04-27 13:00
  • 31. Anh, N. T.
    et al.
    Van Hertem, Dirk
    KTH, School of Electrical Engineering (EES), Electric Power Systems. K.U. Leuven, Belgium .
    Driesen, J.
    Transient stability enhancement by TCSC controllers using remote input signals2010In: 2010. ACDC. 9th IET International Conference on AC and DC Power Transmission, 2010, no 570 CPConference paper (Refereed)
    Abstract [en]

    This paper presents a method to improve the dynamic performance of Thyristor-Controlled Series Capacitor (TCSC) regarding transient stability using remote measurement signals. The remote signals are selected based on their effectiveness for damping the first swings. Phasor Measurement Units are used to measure real-time remote signals and transfer those to the TCSC stability control loop. Transient stability studies are performed for the Vietnamese system, and the benefits of applying TCSCs for the stability enhancement are demonstrated. The case studies show the enhancement of the transient stability comparing control using remote control signals in stead of local signals.

  • 32. Aoun, M. -C
    et al.
    Pešut, D.
    Matosović, M.
    Bošnjak, R.
    Deane, P.
    Glynn, J.
    Gallachóir, B. Ó
    Nagy, S.
    Badouard, T.
    Desbrosses, N.
    Taliotis, Constantinos
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    de Boncourt, M.
    Keramidas, K.
    Gas Security of Supply in the European Union2017In: Europe's Energy Transition: Insights for Policy Making, Elsevier, 2017, p. 67-78Chapter in book (Refereed)
    Abstract [en]

    The EU remains widely dependent on external gas supplies, with imports representing 70% of its consumption in 2013. Member States have different import profiles with divergent levels of dependency on Russian imports. Several European Member States rely heavily on Russian supplies, which shows that the EU gas supply security needs to be examined both from an internal and international perspective. Since the 2009 crisis between Russia and Ukraine, the EU has adopted several legislative tools to strengthen EU gas security of supply. The third legislative package, the security of supply Regulation (EU) 994/2010 and the Energy Infrastructure package identifying Projects of Common Interest have significantly improved the ability of the EU to face import disruptions. However, several countries remain particularly vulnerable to the occurrence of disruption. When considering national production, storage, and the diversity of suppliers, Bulgaria, Czech Republic, Estonia, Finland, Latvia, and Lithuania seem to be at risk. Romania, Poland, and Hungary also import the bulk of their gas from Russia, but have either domestic production or significant storage capacity.

  • 33.
    Arjmand, Mehdi
    et al.
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology.
    Liu, Longcheng
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Neretnieks, Ivars
    KTH, School of Chemical Science and Engineering (CHE), Chemical Engineering and Technology, Chemical Engineering.
    Exergetic efficiency of high-temperature-lift chemical heat pump (CHP) based on CaO/CO2 and CaO/H2O working pairs2013In: International journal of energy research (Print), ISSN 0363-907X, E-ISSN 1099-114X, Vol. 37, no 9, p. 1122-1131Article in journal (Refereed)
    Abstract [en]

    The use of reversible chemical reactions in recuperation of heat has gained significant interest due to higher magnitude of reaction heat compared to that of the latent or sensible heat. To implement chemical reactions for upgrading heat, a chemical heat pump (CHP) may be used. A CHP uses a reversible chemical reaction where the forward and the reverse reactions take place at two different temperatures, thus allowing heat to be upgraded or degraded depending on the mode of operation. In this work, an exergetic efficiency model for a CHP operating in the temperature-level amplification mode has been developed. The first law and the exergetic efficiencies are compared for two working pairs, namely, CaO/CO2 and CaO/H2O for high-temperature high-lift CHPs. The exergetic efficiency increases for both working pairs with increase in task, TH, decrease in heat source, TM, and increase in condenser, TL, temperatures. It is also observed that the difference in reaction enthalpies and specific heats of the involving reactants affects the extent of increase or decrease in the exergetic efficiency of the CHP operating for temperature-level amplification.

  • 34.
    Arvanitis, Konstantinos
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    MACROALGAE IN THE BIOREFINERY: A SUBSTANCE FLOW ANALYSIS AND ENVIRONMENTAL ASSESSMENT OF AN EXTRACTION PROCESS OF THE MAJOR COMPONENTS IN SACCHARINA LATISSIMA2016Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    A turn to more sustainable resources has lead the research during the last decades to algae. Algae is a resource that has been utilized for thousands of years offering a variety of possibilities. Nevertheless modern technology were able to uncover algae’s great potential and pave the way for alternative uses such as biofuel and biomaterial production. Towards that direction, ‘Seafarm’ aims in utilizing algae in the most efficient and sustainable way. For that purpose various steps have been established, including the biorefinery step which entail among other the extraction of carbohydrates from brown algae.

    The current thesis is based on an extraction of carbohydrates from Saccharina latissima, a brown algae species, which was developed by Viktor Öberg during his master thesis at KTH. The aim of this work is to assist in the scaling up of that laboratory process by analyzing the basic steps and substances of the process, investigating its environmental performance and identifying improvement areas for theoretical optimization. The results of the aforementioned analysis include a substance flow analysis which reveals the basic steps of the process and constitute the basis for further analysis. The second step examines the environmental performance of the process based on the chemical selection. Hence the results are a risk assessment of chemicals with performance indicators for each chemical as well as the whole process. The final part provides a theoretical optimization of the process based on literature studies where the recommendations are divided in production optimization and environmental performance.

    The above results constitute the basis of the analysis of the process and sets the foundations for scaling up the process at an industrial level. The current analysis in combination with an energy and economic assessment could be used for the designing of the process and its integration in the biorefinery. 

  • 35.
    Asef, Pedram
    et al.
    Univ Politecn Cataluna, BarcelonaTech, Dept Elect Engn, EEBE, Barcelona 08019, Spain..
    Bargallo Perpina, Ramon
    Univ Politecn Cataluna, BarcelonaTech, Dept Elect Engn, EEBE, Barcelona 08019, Spain..
    Barzegaran, M. R.
    Lamar Univ, Renewable Energy Microgrid Lab, Beaumont, TX 77705 USA..
    Lapthorn, Andrew
    Univ Canterbury, Dept Elect & Comp Engn, Christchurch 8041, New Zealand..
    Mewes, Daniela
    KTH, School of Industrial Engineering and Management (ITM).
    Multiobjective Design Optimization Using Dual-Level Response Surface Methodology and Booth's Algorithm for Permanent Magnet Synchronous Generators2018In: IEEE transactions on energy conversion, ISSN 0885-8969, E-ISSN 1558-0059, Vol. 33, no 2, p. 652-659Article in journal (Refereed)
    Abstract [en]

    This paper studies a dual-level response surface methodology (DRSM) coupled with Booth's algorithm using a simulated annealing (BA-SA) method as a multiobjective technique for parametric modeling and machine design optimization for the first time. The aim of the research is for power maximization and cost of manufacture minimization resulting in a highly optimized wind generator to improve small power generation performance. The DRSM is employed to determine the best set of design parameters for power maximization in a surface-mounted permanent magnet synchronous generator with an exterior-rotor topology. Additionally, the BA-SA method is investigated to minimize material cost while keeping the volume constant. DRSM by different design functions including mixed resolution robust design, full factorial design, central composite design, and box-behnken design are applied to optimize the power performance resulting in very small errors. An analysis of the variance via multilevel RSM plots is used to check the adequacy of fit in the design region and determines the parameter settings to manufacture a high-quality wind generator. The analytical and numerical calculations have been experimentally verified and have successfully validated the theoretical and multiobjective optimization design methods presented.

  • 36.
    Ast, Eric
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    The state of long-term climate action planning in megacities: Planning and demographic trends among 17 of the world’s leading cities aiming to reduce emissions by 80% by the year 20502015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    This report reviews the current state of long-term climate action planning in 17 cities which have publicly communicated carbon reducttargets in line with the IPCC recommended 80% reduction by 2050 (80x50) for stabilizing the impacts of climate change at 2°C.  The aim of this report is to provide a foundation of support for cities in achieving their deep carbon reduction goals through a comprehensive understanding of leading climate action plans and the context under which they were created, including current city emissions and demographic data, climate plan reduction strategies and targets, and feedback on plan creation and needs from city planning staff.  By achieving this aim, cities are in a better position to understand where their plans fit in the global context and connect with other cities around common issues, research institutions have a new benchmark analysis of leading action plans to build further research upon, and city-level climate action organizations have a clearer idea of how to focus efforts in helping cities achieve carbon reduction goals.  This aim is achieved through the application of a framework for comparing city plans and targets, an analysis of current city emissions and demographic data, and synthesis of key findings from city planning staff discussions.  

    Key findings show no clear demographic and environmental biases exist within these 17 cities, indicating long-term climate action planning can be undertaken by cities across the full spectrum of size, climate, and current per capita emissions output, though regional geographic and development bias exists.  Plans for carbon reduction are highly concentrated among a small number of actions, indicating the movement has coalesced around a standard set of strategies for achieving deep carbon reductions.  Finally, the relative newness of plans, with the majority less than 5 years old, and the lack of commonality among cities in emissions methodology and communication of reduction strategies, shifts a short-term focus towards standardization methodologies which enable deeper comparison between cities and plans.

  • 37.
    Awan, Muhammad Rizwan
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Heat and Power Technology.
    Feasibility Study of Vertical Axis wind turbines in Urban areas of Sweden2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
  • 38.
    Awan, Muhammad Rizwan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Riaz, Fahid
    Nabi, Zahid
    Analysis of conditions favourable for small vertical axis wind turbines between building passages in urban areas of Sweden2017In: International Journal of Sustainable Energy, ISSN 1478-6451, E-ISSN 1478-646X, Vol. 36, no 5, p. 450-461Article in journal (Refereed)
    Abstract [en]

    This paper presents the analysis of installing the vertical axis wind turbines between the building passages on an island in Stockholm, Sweden. Based on the idea of wind speed amplification due to the venture effect in passages, practical measurements were carried out to study the wind profile for a range of passage widths in parallel building passages. Highest increment in wind speed was observed in building passages located on the periphery of sland as wind enters from free field. Wind mapping was performed in the island to choose the most favourable location to install the vertical axis wind turbines (VAWT). Using the annual wind speed data for location and measured amplification factor, energy potential of the street was calculated. This analysis verified that small vertical axis wind turbines can be installed in the passage centre line provided that enough space is provided for traffic and passengers.

  • 39. Aziz, M.
    et al.
    Zaini, Ilman Nuran
    KTH, School of Industrial Engineering and Management (ITM), Materials Science and Engineering, Energy and Furnace Technology.
    Production of hydrogen from algae: Integrated gasification and chemical looping2017In: Proceedings of the 9th International Conference on Applied Energy, Elsevier, 2017, Vol. 142, p. 210-215Conference paper (Refereed)
    Abstract [en]

    Due to their high potential and beneficial characteristics, algae is considered as very promising energy source in future. In this study, an integrated conversion system of algae to hydrogen is proposed with the objective of high total energy conversion efficiency. The proposed system mainly covers algal drying, gasification, and chemical looping. To facilitate optimum heat circulation throughout the proposed system, enhanced process integration is adopted. It combines exergy recovery and process integration technologies in order to achieve a wasted energy, hence the total energy efficiency can be improved significantly. In the proposed system, to convert algae to hydrogen, steam gasification and syngas chemical looping are integrated as the main conversion. Iron oxide is employed as the oxygen carrier, and is circulated among the reactors in the chemical looping module. Process modeling and calculation is performed using ASPEN Plus, and the total energy efficiency, including hydrogen production and power generation, is evaluated. Several operating parameters including target moisture content in drying, steam-to-biomass ratio in gasification, and chemical looping pressure, are observed. From the results, it is shown that the proposed system is potential to convert algae to hydrogen with high total energy efficiency, which is higher than 70%. Both target moisture content and steam-to-biomass ratio influence strongly the total energy efficiency. On the other hand, chemical looping pressure show insignificant effect to total energy efficiency.

  • 40.
    Bakhiet, Omnia
    et al.
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology. KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Mustafa, Riham
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology. KTH, School of Architecture and the Built Environment (ABE), Real Estate and Construction Management.
    Biogas Production in Abu Dhabi: An Evaluation based on Energy and Economy (Comparison of two plant designs)2015Independent thesis Basic level (degree of Bachelor), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Abu Dhabi, which is the capital city of the United Arab Emirates, is known for its fast and advanced development in a short period of time. The city however generates a large amount of waste on a daily basis and a large amount of this is dumped or landfilled. Landfilling of the organic fraction of municipal solid waste (OFMSW), contributes to greenhouse gas (GHG) emissions and circa 80 % of the OFMSW is landfilled in Abu Dhabi. However, Abu Dhabi has shown its commitment to reducing GHG emissions by aiming to generate 7% renewable energy by 2030, improving waste management, and developing a strategy for green economy. In this study the approach evaluated is the waste-to-biogas system which utilizes anaerobic digestion of the OFMSW. Modules based on the Aikan® and REnescience® plant designs were simulated using SuperPro Designer® where energy and economic values were obtained and used for the evaluations. Excel was used to make a cash-flow analysis for both modules. A SWOT analysis was conducted to compare the strengths, weaknesses, opportunities and threats between both modules.

    Energy Returned on Investment is an approach that calculates the efficiency of a fuel by dividing the energy acquired by the energy required in a process. Both modules give an energy returned on investment (EROI) ratio for biogas of slightly below 2:1, in regards to electricity which is considered relatively low when compared to other fuels. Three methods were used for calculating the profitability of the modules, internal rate of return, pay-back period and net present value (NPV). However the net present value (NPV) was found most reliable and showed an NPV of $500 000 and $3 000 000 for module one and two respectively and calculations show that module one has more risks while module two could result in a bigger risk monetarily. The results show that implementing such a system will have a minimal contribution to the city’s aim of 7 % renewable energy generation. However, it will contribute to the city’s target of reducing GHG emission, improve waste management, and lead to a green economy. 

  • 41. Balram, Pavam
    et al.
    Tuan, Le Anh
    Bertling Tjernberg, Lina
    KTH, School of Electrical Engineering (EES), Electromagnetic Engineering.
    Centralized charging control of plug-in electric vehicles and effects on day-ahead electricity market price2015In: Plug In Electric Vehicles in Smart Grids, Springer, 2015, p. 267-299Chapter in book (Refereed)
    Abstract [en]

    Global policy targets to reduce greenhouse gas emissions have led to increased interest in plug-in electric vehicles (PEV) and their integration into the electricity network. Existing electricity markets, however, are not well suited to encourage direct participation of flexible demand from small consumers such as PEV owners. The introduction of an aggregator agent with the functions of gathering, aggregating, controlling and representing the energy needs of PEV owners in the electricity market could prove useful in this regard. In this chapter, a mathematical model of PEV aggregator for participation in the day-ahead electricity market is described. The modeling is done by treating each of the individual vehicle batteries as a single large battery. The centralized charging and discharging of this battery is then scheduled based on the traveling needs of the PEV owners determined by an aggregated driving profile and the cumulative electrical energy needs of vehicles over the optimization horizon. Two methods for scheduling PEV demand named as joint scheduling method (JSM) and aggregator scheduling method (ASM) are presented. The two methods are subsequently used to observe the effects of introducing flexible scheduling of PEVs on the day-ahead market price in an IEEE test system and a Nordic test system. Results from the IEEE test system case studies will indicate that the scheduling of PEV energy through direct centralized control at high PEV penetration levels of 50 % or greater could lead to potential lowering of day-ahead market prices as compared to an indirect control method such as the use of fixed period charging. Results from the Nordic test system case study shows that controlled scheduling of PEV demand could lead to only a small increase in day-ahead market price of electricity.

  • 42.
    Baradar, Mohamadreza
    et al.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Hesamzadeh, Mohammad R.
    KTH, School of Electrical Engineering (EES), Electric Power Systems.
    Calculating Negative LMPs from SOCP-OPF2014In: ENERGYCON 2014 - IEEE International Energy Conference, IEEE Computer Society, 2014, p. 1461-1466Conference paper (Refereed)
    Abstract [en]

    Recent research shows that non-convex OPF problem can be recast as a convex Semidefinite Programming (SDP) problem or Second Order Cone Programming (SOCP) problem. However, in the most SOCP OPF problems, there are some cases that conic relaxation results in a miscalculation of negative Local Marginal Prices (LMPs). This paper reviews the SOCP formulation of the optimal power flow problem proposed in [1] and then proposes one way of generating negative Locational Marginal Prices, LMPs, using this SOCP formulation. The proposed model is coded in GAMS and its built MOSEK solver and tested on a modified version of IEEE-30 test system.

  • 43.
    Barås, Madeleine
    KTH, School of Architecture and the Built Environment (ABE), Sustainable development, Environmental science and Engineering, Industrial Ecology.
    Assessing the environmental sustainability of an apparel supply chain: the development of a conceptual model based on a comparative study of preferred tools and actual practices2015Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    The apparel and textile industry is one of the largest in the world and is characterised by complex, global supply chains, water and chemical intensive processes as well as environmentally harmful raw material extraction and production. Because of this, environmental sustainability has become a key issue for the businesses in recent years. With this in mind, and considering an increasing demand for textile and apparel goods, the industry is in urgent need of improving the environmental footprint of its products. However, lack of transparency and available data throughout apparel supply chains decrease chances of producing accurate sustainability assessments, which in turn obstruct improvement measures. Moreover, companies often lack the in-house competence required to manage and create strategies for sustainability assessments.

    In this study an overview of an apparel supply chain is provided, highlighting phases, sub phases, input and environmental indicators. Appropriate tools for assessing the environmental sustainability of such a supply chain are inventoried and examined. Based on a case study, a literature review and a stakeholder opinion assessment, misalignments between actual practices within an apparel company and recommended practices of the researcher and stakeholder communities are uncovered. These identified misalignments enabled the development of a conceptual model, aiming at facilitating the process of developing an environmental sustainability assessment strategy within an apparel company. 

  • 44.
    Basar, Ezgi
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Applied Thermodynamics and Refrigeration.
    Capacity Building for Energy Performance Contracting in European Union2013Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    Energy Performance Contracting (EPC) is an important tool to disseminate energy efficiency measures. This study focuses on the main barriers and success factors for EPC market in order to build capacity in this subject. A pilot study of questionnaire took part among the local authorities of four countries within the European Union; Croatia, Denmark, Czech Republic and Slovakia. The results of this pilot study were combined with the results of a literature research to identify common disadvantages and key points of the market. Afterwards, the most important actions to be taken on national and international level in European Union were discussed. According to this study, the supportive legal framework for the energy efficiency measures, access to financial resources, reliable energy consumption data and trust in Energy Service Companies (ESCOs) were remarked as the essential factors for increasing the capacity of the EPC.

  • 45.
    Bateebe, Irene
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology.
    Investigation of Probable Pollution from Automobile Exhaust Gases in Kampala City, Uganda: To Assess the current automobile exhaust gas emission levels and characterize the emissions from different automobile types2011Independent thesis Advanced level (degree of Master (Two Years)), 20 credits / 30 HE creditsStudent thesis
    Abstract [en]

    It is estimated that transport sources in developing countries contribute about 4% of the global fossil carbon dioxide versus 18% by industrialized countries. The cost of urban air pollution is estimated to be 2% of GDP in developed countries and more than 5% in developing countries. With an annual vehicle registration growth of over 30% in 2008 and a population growth rate of 6%, the number of automobiles in Kampala city of Uganda is expected to continue growing exponentially. Most of the vehicles used are imported into the country when quite old with worn out engines and low energy efficiencies. As a result, such vehicles profusely emit exhaust gases which may be harmful to both human health and the environment. Controlling pollution from the transport sector is vital to improving the quality of air and protecting public health. The objective of this dissertation was to determine the level of pollution from automobile exhaust gases in Kampala City and its impacts on human health and the environment. The study involved the analysis of tail pipe emissions using a gas analyser. It covered mini buses, motorcycles and personal vehicles which constitute 92% of the Kampala vehicle parc. It was established that the main types of exhaust gases from the automobiles were CO2,  NOx, CO, NO and HC. The findings estimated the highest level of NOx tail pipe emissions at 0.15 mg/m3, HC emissions at 2.59 mg/m3, CO at 110 mg/m3 and 286.6 mg/m3 for CO2. The reported ambient air emissions were estimated at 0.18 ppm, 14000 ppm and 1.3 ppm corresponding to NO2, CO2 and CO, respectively. The study further investigated the impact of four mitigation methods on emission levels using the LEAP model. The impact of increasing penetration of city buses, introduction of tail pipe emission standards and hybrid cars and improvement of vehicle fuel economy were investigated. It was found that if left unabated, the emissions will continue to grow with the increasing number of motor vehicles. Implementation of the proposed mitigation methods resulted in a reduction in the GWP reduced by 52%, 51%, 17% and 8.5%, respectively. It is recommended that a comprehensive motor vehicle pollution control program be designed to implement the proposed NEMA vehicle emission standards. Establishment of an integrated transport system promoting the growth in number of city buses should be made a priority to reduce on emission levels and enable the decongestion of Kampala city.

  • 46. Bauner, D.
    et al.
    Fones-Sundell, M.
    Njau, K. N.
    Walsh, T.
    Cerin, Pontus
    KTH, School of Industrial Engineering and Management (ITM), Industrial Economics and Management (Dept.). Umeå School of Business, Sweden .
    Financing and investment for sugar cane and bioenergy in Africa2013In: Bioenergy for Sustainable Development and International Competitiveness: The Role of Sugar Cane in Africa, Taylor & Francis, 2013, p. 390-415Chapter in book (Refereed)
  • 47. Bazilian, M.
    et al.
    Miller, M.
    Detchon, R.
    Liebreich, M.
    Blyth, W.
    Futch, M.
    Modi, V.
    Jones, L.
    Barkett, B.
    Howells, M.
    MacGill, I.
    Kammen, D. M.
    Mai, T.
    Wittenstein, M.
    Aggarwal, S.
    O'Malley, M.
    Carvallo, J. P.
    Welsch, Manuel
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Pugh, G.
    Weston, R.
    Arent, D. J.
    Accelerating the global transformation to 21st century power systems2013In: Electricity Journal, ISSN 1040-6190, E-ISSN 1873-6874, Vol. 26, no 6, p. 39-51Article in journal (Refereed)
    Abstract [en]

    Nations and regions need to share lessons about the best ways to create enabling policies, regulations, and markets that get the most social benefit out of power systems and incent the necessary investments.

  • 48.
    Bazilian, Morgan
    et al.
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Chattopadhyay, D.
    Considering power system planning in fragile and conflict states2016In: Energy for Sustainable Development, ISSN 0973-0826, Vol. 32, p. 110-120Article in journal (Refereed)
    Abstract [en]

    Traditional methods of energy planning are likely to provide results that may be inappropriate in fragile and conflict-prone countries. The risks of violence and damage, or significant delays and cancellations in infrastructure development, are rife in these states. Thus, least-cost planning processes must explicitly address the inherent risks. While there are numerous statistical methods for dealing with decision making under uncertainty, few of them have been applied to power system planning and tailored for these situations. We present a general theoretical framing of the issue and illustrate application of a very simple method to a case study of the Republic of South Sudan. We find that, in general, the resilience aspects, combined with modular and incremental benefits of distributed generation technologies and systems, emerge as attractive options if the various risks of infrastructure development are included in modelling techniques.

  • 49. Bazilian, Morgan
    et al.
    Rice, Andrew
    Rotich, Juliana
    Howells, Mark
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    DeCarolis, Joseph
    Macmillan, Stuart
    Brooks, Cameron
    Bauer, Florian
    Liebreich, Michael
    Open source software and crowdsourcing for energy analysis2012In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 49, p. 149-153Article in journal (Refereed)
    Abstract [en]

    Informed energy decision making requires effective software, high-quality input data, and a suitably trained user community. Developing these resources can be expensive and time consuming. Even when data and tools are intended for public re-use they often come with technical, legal, economic and social barriers that make them difficult to adopt, adapt and combine for use in new contexts. We focus on the promise of open, publically accessible software and data as well as crowdsourcing techniques to develop robust energy analysis tools that can deliver crucial, policy-relevant insight, particularly in developing countries, where planning resources are highly constrained-and the need to adapt these resources and methods to the local context is high. We survey existing research, which argues that these techniques can produce high-quality results, and also explore the potential role that linked, open data can play in both supporting the modelling process and in enhancing public engagement with energy issues.

  • 50. Bazilian, Morgan
    et al.
    Rogner, Holger
    Howells, Mark
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Hermann, Sebastian
    KTH, School of Industrial Engineering and Management (ITM), Energy Technology, Energy Systems Analysis.
    Arent, Douglas
    Gielen, Dolf
    Steduto, Pasquale
    Mueller, Alexander
    Komor, Paul
    Tol, Richard S.J.
    Yumkella, Kandeh K.
    Considering the energy, water and food nexus: Towards an integrated modelling approach2011In: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 39, no 12, p. 7896-7906Article in journal (Refereed)
    Abstract [en]

    The areas of energy, water and food policy have numerous interwoven concerns ranging from ensuring access to services, to environmental impacts to price volatility. These issues manifest in very different ways in each of the three "spheres", but often the impacts are closely related. Identifying these interrelationships a priori is of great importance to help target synergies and avoid potential tensions. Systems thinking is required to address such a wide swath of possible topics. This paper briefly describes some of the linkages at a high-level of aggregation - primarily from a developing country perspective - and via case studies, to arrive at some promising directions for addressing the nexus. To that end, we also present the attributes of a modelling framework that specifically addresses the nexus, and can thus serve to inform more effective national policies and regulations. While environmental issues are normally the 'cohesive principle' from which the three areas are considered jointly, the enormous inequalities arising from a lack of access suggest that economic and security-related issues may be stronger motivators of change. Finally, consideration of the complex interactions will require new institutional capacity both in industrialised and developing countries.

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