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Recognising the future leaders of Energy Research is fundamental to safeguarding tomorrow's driving force in innovation. This collection will showcase the high-quality work of internationally recognized researchers in the early stages of their careers. We aim to highlight research by leading scientists of the future across the entire breadth of Energy Research, and present advances in theory, experiment and methodology with applications to compelling problems.

Energy Crisis! Electricity Price drama! The threat of global energy poverty! Media are generous with spectacular titles. Yes, energy is important, and yes, nearly all societal challenges are connected to how we convert, distribute and use energy. Therefore, the KTH Energy Platform and KTH Library presented an exhibition with the theme Towards the energy of the future – the invisible revolution behind the electrical socket. The exhibition displayed showcase illustrations from the book made by Lotta Waesterberg Tomasson, as well as books related to energy and electricity from the KTH Library's collections. In parallell with the exhibition, a series of live popular science lunch seminars with presentations of selected chapters of the book took place. As part of the exhibition, students from KTH's Electrical Engineering program also showcased exciting projects that connect to the anthology’s contents, made with materials and equipment from the student-driven ELAB and “Studentverkstan”. Visitors were also invited to share their reflections and ideas on energy., QC 20230530

Objectius de Desenvolupament Sostenible::5 - Igualtat de Gènere, Objectius de Desenvolupament Sostenible::7 - Energia Assequible i No Contaminant, Postprint (published version)

Combined diffusion, migration, and advection of ions in a binary electrolyte plays a role in various applications, including water electrolysis, electrodeposition, deionization, and electrophoresis. Here we analyze a dilute binary electrolyte with arbitrary ion valencies in a porous or nonporous medium using the one-dimensional Nernst-Planck equations. We examine how advection influences the limiting current, diffusion potential, and overall potential, deriving broadly useful analytical expressions. We provide experimental results for the electro-osmotic flow through a submicroporous separator in an alkaline water electrolysis setup. The time evolution of the potential is followed from the initial timescale of double-layer charging, followed by the diffusional timescale, to the time at which a limiting current is reached. For the longer timescales, a quasisteady model is shown to predict the time evolution of the advection-modified potential drop reasonably well. Additional interesting features arising due to electro-osmotic drag and unsteady diffusion are observed and explained., Energy Technology

The European Commission organises every year, in cooperation with the Group of Experts referred to in Article 31 of the Euratom Treaty, a scientific seminar on emerging issues in radiation protection – generally addressing new research findings with potential policy and/or regulatory implications. Leading scientists are invited to present the status of scientific knowledge in the selected topic. Based on the outcome of the scientific seminar, the Group of Experts referred to in Article 31 of the Euratom Treaty may recommend research, regulatory or legislative initiatives. The European Commission takes into account the conclusions of the Experts when setting up its radiation protection programme. The Experts' conclusions are valuable input to the process of reviewing and potentially revising European radiation protection legislation.

© 2020 International Solar Energy Society With the increasing demand for air-conditioning and refrigeration and depleting fossil fuel resources, countries across the globe have been exploring sustainable alternatives to supply cooling loads. While solar cooling technology has been investigated and demonstrated in recent decades, it has not yet been able to take over traditional cooling systems due to the technical and financial constraints. Understanding the state of the art in this emerging research field is crucial in planning future research efforts. In light of this motivation, this study uses bibliometric analysis to identify hot topics, trends, and research clusters in solar cooling. A dataset of 3639 publications on solar cooling obtained from Web of Science has been analyzed using (i) the open source tool VOSviewer, (ii) the R package Bibliometrix and (iii) an in-house bibliometric tool. This analysis allowed us to determine the annual publication rate both total and segregated by country, author, journal, and research institution. With an overall increasing trend in the total number of publications, China was identified as the leading country in solar cooling research followed by the USA, and Southern European countries. Keyword analysis and time evolution of various key solar cooling technologies have shown that the focus has so far been on solar thermal cooling technology. Nonetheless, as solar photovoltaic prices drop significantly, researchers are expected to focus more closely on photovoltaic driven cooling systems in the near future as a step towards reducing fossil fuel dependence and mitigating climate change.

A session chaired by SAGUF at the International Foresight Academic Seminar 2013 identified strengths and gaps in the energy research landscape in Switzerland. The discussion highlighted the need for inter- and transdisciplinary research and integration of the social sciences.

This research letter discusses elements of a long-term interdisciplinary research effort needed to help ensure the maximum social, economic, and environmental benefits of achieving secure universal access to modern energy services. Exclusion of these services affects the lives and livelihoods of billions of people. The research community has an important, but not yet well-defined, role to play., QC 20160728

Solar Energy Research Center SERC started at Högskolan Falun Borlänge – now Dalarna University - in November 1984 as the first research center at any Swedish University College. Gradually it has grown from a small and not always by its environment appraised institution into Sweden's leading research center in its field. European Solar Engineering School ESES was originally intended to be established on the Italian island of Capri, but began as a Master Program at Dalarna University at the beginning of the fall semester 1999. ESES attracts students from all over the world and has today a reputation of one of the world's best educations in its field. My own role was to initiate SERC and ESES and being instrumental in their respective first years of development, while their continued growth has depended highly on my former colleagues, still active at Dalarna University.

Provides information about the U.S. Department of Energy (DOE) and its predecessor agencies and how DOE influences federal energy policy and scientific research in the western U.S.

This paper analyses the following seven sub-fields of Sustainable Energy Research with respect to the influence of conference paper dominance on citation patterns across citing and cited document types, overall sub-field and document type impacts and citedness: Wind Power, Renewable Energy, Solar and Wave Energy, Geo-thermal, Bio-fuel and Bio-mass energy sub-fields. The analyses cover research and review articles as well as conference proceeding papers excluding meeting abstracts published 2005-09 and cited 2005-11 through Web of Science. Central findings are: The distribution across document types and cited vs. citing documents is highly asymmetric. Predominantly proceeding papers cite research articles. With decreasing conference dominance the segment of proceeding papers citing proceeding papers decreases (from 22 % to 14 %). Simultaneously, the share of all publication types that actually are proceeding papers themselves citing proceeding papers decreases (from 35 % to 11 %).The proceeding paper citation impact increases in line with the probabilities that the sub-field’s overall as well as proceeding paper citedness increase; and progressively more citations to proceeding papers derive from journal sources. Distribution of citations from review articles shows that novel knowledge predominantly derives from research articles – much less from proceeding publications.

How to use automatically read data to create a method that visually describes how energy is used in a building, the so called energy signature.

The aim of this master thesis was to find and grade suitable sites for wind turbines in the rural district of Lerum at the reguest of Göteborg Energi. The rural district of Lerum consists of very complicated terrain which was the reason why we picked Lerum. The assignment was achieved by using the software program ArcGIS and its attendant tools. In step 1 an overall analysis was made in order to sort out the least suitable sites. Step 2 consisted of a 3D analysis in ArcScene together with a more precise analysis in ArcMap. As result we found two interesting sites, which met our demands and specific constraints. The sound emission parameter was the most important parameter due to its significant influence on interesting sites.

The purpose of this master thesis is to investigate how nearby forests affect the energy production in wind turbines. To reach the purpose a case study is performed on three wind turbines sited on a field in a north-south line at Andersfält in the municipality of Halmstad, Sweden. Approximately 100 meters south of the southern wind turbine a forest is situated. The case study is divided into three sub studies where the difference in energy production, the affect of the forest and a wind meteorology model, WAsP, is studied. The result show that the forest have a significant influence and that the WAsP-model gives an incorrect result of the energy production in wind turbines sited near a forest.

The purpose of the numerical study was to investigate the influence of three different natural gas compositions on the combustion behaviour of an Advanced Environmental Vortex (AEV) burner. The flow conditions apply to the AEV burners installed in the Siemens gas turbine SGT-800. Numerical simulations were carried out using the software Chemkin 4. Ignition temperatures, adiabatic flame temperatures, NOX emissions and laminar flame speeds were determined using models included in the software. To find suitable reaction mechanisms for the simulations a mechanism study was made. The behaviour of the mechanisms was studied burning methane and ethane. The two reaction mechanisms chosen for the simulations represent combustion of hydrocarbons with up to two carbon atoms and seven carbon atoms. The reaction mechanisms are developed by Danmarks tekniske universitet and Lawrence Livermore National Laboratory respectively. The simulations gave the following results. The ignition temperature differed up to 80 K and the adiabatic flame temperature up to 30 K between the gases. The highest NOX emissions were obtained at =0.95 and increased with the residence time. The largest difference in laminar flame speed was 10 cm/s. The conclusion from the results when applied to the conditions in the AEV burner is that the difference in gas composition does not influence the performance of the burner noticeably. However some differences in NOX emissions are noticed but since NOX emissions are difficult to predict the levels of the emissions are to be treated with caution.

This thesis gives a thorough description of the icing mechanisms in gas turbines, the underlying physics of ice and ice types that can form in gas turbines. The primary intention of this thesis is to investigate the icing condition regions leading to ice formation in gas turbines. The icing problem in gas turbines is explained in detail in this thesis. The different ice types, icing mechanism in gas turbines and ambient conditions leading to icing are reported. Ambient factors and other factors that can affect icing conditions are also discussed. The icing conditions have been investigated for different air velocities in the inlet system of the gas turbine and with various ambient conditions. A recovery factor has been used in the calculations of icing conditions. The recovery factor gives the icing surface temperature which lies between the air static temperature and air total temperature. The recovery factor differs from laminar till turbulent flow. The experimental value 0, 8 is taken in the calculations. Ice formation locations in the gas turbines? inlet systems are also covered. My study to the icing mechanism in gas turbines shows that there is no hazard for icing when air velocity is very high because of great air temperature depression. Furthermore, as long as the surface temperature is above the water saturation temperature, condensation will not occur and ice will not form even if the surface temperature is below freezing point temperature. The highest risk of ice building lies specifically between the highest and lowest velocity, in contrast to what was believed earlier that the risk lied at highest velocity. A possible solution to the icing problem in gas turbines is also presented in this thesis. The different anti icing systems that can protect the gas turbine is investigated. I focused mainly on the compressor bleed heating system and hot water heat exchanger system in my calculations. The heat power that is needed to warm up the incoming air to the g

Europaparlamentet antog i december 2002 ett direktiv om byggnaders energiprestanda. Direktivet kräver att byggnader skall energideklareras, alltså undersökas och dokumenteras ur ett energiprestandaperspektiv. Direktivet har hittills resulterat i två svenska delbetänkanden samt ett slutbetänkande. Dessa tre skrifter kommer att ligga till grund för den svenska lagen om energideklarationer. Enligt SOU 2005:67 skall energiprestandan beräknas för samtliga småhus och nybyggda hus. För flerbostadshus och byggnader med lokaler skall energiprestandan beräknas då det inte finns några uppgifter på byggnadens energianvändning. Eftersom byggnaders energiprestanda är en central del av energideklarationerna ägnas det en utförlig analys av olika energiflöden ut ur och in i en byggnad. Infallsvinkeln i analysen av byggnaders energibalans är att betrakta en byggnad som ett öppet termodynamiskt system med klimatskalet som systemgräns. Ett termodynamiskt öppet system kan utbyta värme med omgivningen genom ledning, strålning, konvektion och massutbyte. Det som skiljer ett öppet och ett slutet termodynamiskt system är att ett slutet system inte tillåts ha något massutbyte med omgivningen. EVU Energi och VVS Utveckling AB vill veta om energideklarationer kan vara ett område som de kan börja arbeta med eftersom det kommer att skapa en ny marknad för energikonsulter. De vill även införskaffa ett beräkningsprogram viket de kan använda för att beräkna byggnaders energiprestanda dels i sitt nuvarande arbete, dels i ett eventuellt framtida arbete med energideklarationer. Rapporten innehåller en beskrivning av en energiinventering med EVU och en jämförelse mellan det tänkta arbetssättet i energideklarationerna och EVU:s arbetssätt. EVU utför energiinventeringar av byggnader för att fastställa hur energibalansen ser ut och undersöka möjligheterna till energihushållningsåtgärder. EVU:s energiinventeringar är mer fokuserade på byggnadens värmesystem och mindre på dess klimatskal än vad energideklar

The interest for wind power has increased in Sweden. Northern Sweden is especially interesting due to that a new wind resource map shows that there are areas in northern Sweden that have more potential for wind power than what have been known before. Therefore E.ON Vind is interested in finding out if, and where, there are suitable places for establishment of wind power in northern Sweden. The purpose of this master thesis is therefore to perform an inventory of northern Sweden for suitable places for wind power. The master thesis is performed at E.ON Vinds office at Vasagatan in Stockholm. Parts of the result will not be official since this is commercial information for E.ON Vind. A general conclusion of the master thesis is that northern Sweden is indeed interesting for establishment of wind power and there are several companies looking for suitable places for wind power in northern Sweden.

Ekonomiska styrmedel som skatter, certifikat och handel med utsläppsrätter påverkar lönsamheten i ett kraftvärmeverk. Det är viktigt för investerare att ha god insyn i tendenser och förändringar på styrmedelsområdet, eftersom det kommer att påverka investeringsobjektets framtida lönsamhet. I arbetets andra del undersöks hur styrmedelsförändringar påverkar lönsamheten för större investeringar i kraftvärmeverk med naturgas, avfall och biobränslen.

The aim of this collaboration, between the division of Thermal Power Engineering and Lunds Energi AB, is to investigate the possibilities of training artificial neural networks (ANNs) with power plant operational data. For this purpose operational data from Lunds Energi's gas turbine GT10B with heat recovery unit (HRU) will be used. Furthermore a model with user interface is created to demonstrate the possibilities of using ANN. The results are evaluated through feedback from Lunds Energi and many different areas of implementation are considered. ANN differs from conventional mathematical models in the sense that they are trained rather than programmed. During training, data is presented in an iterative manner in order to find the relation between selected inputs and outputs. After the network is trained the weights, i.e. the parameters containing the network information, are locked and if the network is presented with new, before unseen, data it is able to predict new outputs. The software used for modeling ANNs is called NeuroSolutions. The resulting networks have been processed in Visual Basic for final use in Excel. Thru these studies several ANN models have been produced, both models of the gas turbine (GT) and models for sensor validation (SV). The results have been promising, e.g. with networks demonstrating high performance predictability.

Ladugårdsmarken är en skola med hög energianvändning och det är främst elanvändningen som bidrar till de höga siffrorna. Eftersom byggnaden renoverades 1991 borde inte energianvändningen vara så hög som den är. Energiförlusterna beror till största delen på bristande isolering i byggnadens omslutande delar, dåligt U-värde på fönster och ett felaktigt konstruerat golvvärmesystem. Att belysningen ofta är tänd och saknar någon form av styrning samt att datorerna ofta står på stand-by bidrar också till den höga elanvändningen. Även ventilationens styrning skulle kunna anpassas bättre till verksamheten för att minska energiåtgången.

Mål - Att spara 1 GWh underhållsenergi på Karlshamsverket. Metod - Att lokalisera de största energisänkorna på kraftverket, göra mätningar eller uppskattningar på hur mycket energi dessa förbrukar, för att där efter ge förslag på tekniska åtgärder, med tillhörande ekonomiska beräkningar som ska reducera energiförbrukningen.

Öresundskraft AB has a number of plants that produces mainly electricity and district heat to the city of Helsingborg and its surroundings. Västhamnsverket is the main plant of the company, with an installed capacity of 126 MW electricity and 186 MW heat. Västhamnsverket is a hybrid combined heat and power plant. In order to demonstrate an efficient control-monitoring model, several ANN models have been developed for different parts of Västhamnsverket. This master thesis is a part of a continuing ANN study applied at Västhamnsverket. The overall aim of this study is to develop an ANN simulator for the whole steam process at Västhamnsverket. In order to develop a better ANN model for the entire steam process, this process is divided into two sub-models, called case 1 and case 2. Consequently two cases have been studied separately and two different ANN models have been developed. These are then linked to each other.

Anaerobic digestion and the production of biogas can provide an efficient means of meeting several objectives concerning energy, environmental and waste management policy. Interest in biogas is increasing, and new facilities are being built. There is a wide range of potential raw material, and both the biogas and digestates produced can be used in many different applications. The variation in raw materials and digestion processes contributes to the flexibility of biogas production systems, but at the same time makes their analysis and comparison more complicated. In this thesis, the energy performance in the life cycle of biogas production is assessed, as well as the environmental impact of introducing biogas systems to replace various fuels and existing strategies for the handling of various raw materials. The energy performance and environmental impact vary greatly between the biogas systems studied depending on the raw material digested and the reference system replaced. The results are largely dependent on the methodological assumptions made, for example, concerning focus, system boundaries, and how the energy required in joint operations is allocated to the raw materials digested. Many of the environmental implications depend on how changes resulting from non-energy-related aspects of the implementation of biogas production can be taken into account. For example, changes in emission of methane and ammonia from the handling of the raw material or changes in nitrogen leaching from arable land. There are several potential barriers to the successful implementation of biogas production. The aspect to which most attention was devoted here was the prospect of using digestate from large-scale biogas plants as a fertilizer in agriculture. Reliable and generally accepted disposal of the comparatively large amounts of digestate produced is necessary if biogas production is to be implemented. Agriculture is currently the most common, and sometimes the only suitable means o

Within the ongoing development of Alstom's latest heavy-duty gas turbine, the motivation for this thesis is the need for a fuel gas pressure prediction software. The key challenge in the development of such a software is finding the model that predicts the pressure drop over the burner hardware. This model has to predict fuel pressure for over critical and under-critical flow over the entire load range with high accuracy. Old models are inadequate for predicting pressure drops at critical conditions. Four main fuel pressure prediction models are presented in this work. The Kv-model is a model where a pressure drop is attributable to a flow resistor and it contains one hardware parameter. By introducing a second hardware parameter the model is refined to work also for over-critical flow conditions. The outflow model is a model in which the fuel pressure drop can be calculated as being only due to the discharge through a nozzle. The two stage-model is a model, which combines the Kv-model, and the outflow model in order to offer a more sophisticated version. It contains the two hardware parameters from the models described above. Four variants of this model are herewith investigated, in which these parameters are considered either constant, Reynolds number-dependent or dependent of critical flow effects. Finally, by means of a nominalization of the variables, a polynomial fitting method, using the least squares procedure, provides the so-called polynomial model. Polynomials of second and fourth order are considered. In order to perform a structured and systematic selection between the different models, three design criteria were defined: accuracy, simplicity and physicality. It is shown that a modified version of the Kvmodel, in which the burner hardware is treated a pure flow resistor, is the best compromise between these design criteria. This model will predict fuel pressures with a high accuracy over the entire load range of the engine and also predict well for dilu

Arbetet går ut på att genomföra en miljö- och energianalys av två pressgrupper i processhallen. Detta innebär att dagens process skall analyseras för att se om man genom olika system kan göra arbetsklimatet bättre för operatörerna samtidigt som en besparing av energi möjliggörs.

The indoor climate system, which serves a building with a proper indoor air quality and thermal comfort, has been predominantly designed based on the initial cost. A life cycle approach could improve both the economic and environmental performance since the energy use could decrease. There has been a lack of knowledge, models and tools for determining the life cycle cost (LCC) for an indoor climate system. The objective of this research project is to propose a model and a PC program for calculating the LCC for indoor climate systems. Focus is on indoor climate systems in Sweden for premises and dwellings. This thesis presents the LCC model and addresses some questions about input data and indoor climate system design through seven appended papers. The indoor climate systems included in the LCC model have different principles for supplying air, extracting air, recovering heat, controlling the airflow rate and supplying heating and cooling to the building. The LCC includes initial costs for purchasing and mounting the components. The LCC also includes running costs for energy, maintenance and repair. Space loss due to indoor climate system components is taken into account in the form of an annual rent loss. A work productivity cost related to ventilation airflow rate and indoor temperature can be added. A scrap value can also be added. According to LCC techniques, all future costs are discounted to the value of today, which is the net present value method. Some results from the PC program implementation in its present state are given. The results from the LCC model can help to choose the system with the lowest LCC for a particular situation. The results can also help to focus the development of indoor climate systems on parameters that are the most important to get systems with lower energy use, which can help to reach the environmental aims of society. In the future, verifications and refinements of the proposed LCC model hopefully will take place.

With the increasing concerns about our environment and human health, more and more stringent emission limits have been specified. These adopted and still coming emission limits require and promote more accurate, less experiential methods to design and develop the combustors. In this thesis, computation fluid dynamics (CFD) technology, based on large eddy simulation (LES) and level set G-equation methods, is applied to study the turbulent premixed combustion related problems. This thesis work consists of three parts. First, this thesis studies the flow structures of isothermal turbulent swirling flows in a dump combustor related geometry, and compared the simulation results with corresponding experimental data. The aims are to gain deeper understanding of the flow and turbulence structures in dump combustors and to examine the capability of LES for prediction of turbulent swirling flows. With appropriate inflow, outflow boundary conditions, and fine grid resolution, LES successfully simulates the vortex breakdown, and the anisotropic turbulence structures for all the swirl numbers considered. Large-scale motion of the vortex core center, i.e. the so-called precessing vortex core (PVC) phenomenon, is predicted. The PVC is found to rotate around the combustor axis at a frequency about 18?25 Hz (Strouhal number about 0.17?0.4). To model the turbulent premixed combustion processes, a level set G-equation is first derived in the LES framework. Some aspects of the level set G-equation have also been addressed in detail in this dissertation. This level set G-equation combined with the stationary flamelet library is used to simulate a lean premixed propane/air flame in a jet engine afterburner. The results indicate that the fluctuation of the flame surface, which is responsible for the broadening of the time averaged mean flame brush by turbulence, depends on the large resolved turbulence eddies. Time averaged mean flow velocity, temperature and major species concentrations

The global climate change caused by emissions of greenhouse gases from combustion processes has been recognized as a continuously growing problem and much research focuses on improving the environmental performance of gas turbines. The potential of improving gas turbine component efficiencies has become smaller each decade and therefore, thermodynamic cycles have become more interesting for power producing units. One of these cycles is the evaporative gas turbine cycle, also known as the humid air turbine. This thesis presents a theoretical model developed for the humidification tower in an evaporative gas turbine. The developed theoretical model has been validated with measurements from experiments conducted in a 600 kWe pilot plant. This thesis presents the installation of a plate heat exchanger in the pilot plant. The experience from the pilot plant is used in a comparative study. This study evaluates the influence of the aftercooler on the performance of the evaporative gas turbine. A test facility for evaporation processes at elevated pressures and temperatures have been built. Evaporation of binary mixtures into a compressed air stream has been performed. Experimental studies with the pilot plant have revealed that it is possible to use a plate heat exchanger as aftercooler in the evaporative gas turbine. The pressure drop on the air side in the aftercooler has been experimentally determined to 1.6% and the pinch-point to 0.1°C. The reconstruction of the pilot plant from a simple cycle to an evaporative cycle has resulted in an increase in thermal efficiency from 21% to 35%. A theoretical model has been developed for the humidification process that predicts the height of the humidification column with an error of 10?15%. Thermodynamic analysis of the bio-EvGT has been performed which have showed that the bio-EvGT cycle has an optimum efficiency of 34%. Further thermodynamics analysis has indicated that the bio-EvGT is a viable alternative to the biomass fueled

Renewable energy will play an important role in the transition to a sustainable energy system. With an increased maturity of renewable energy technologies, issues concerning implementation are becoming more important. The decisions and actions of municipalities and other local actors have a significant influence on the implementation of renewable energy. In this thesis challenges to implementation at the local level in Sweden are analysed for two types of renewable energy technologies: biogas and wind power. The thesis is based on six case studies where written documents and semi-structured qualitative interviews have been the main sources of material. Two research themes are explored. In the first theme the planning and management of locally based renewable energy projects is studied. It is shown that project planning, concerning biogas projects in particular, can be complex and that the conditions of planning can vary considerably between projects. The results indicate that different planning approaches are appropriate for different projects and flexibility is identified as a key aspect of project planning. The second theme deals with conflicts related to the siting of renewable energy facilities, and how these are handled in land-use planning through citizen participation. It is shown that there are both differences and similarities when comparing traditional siting conflicts with those concerning renewable energy facilities. Different theoretical perspectives on siting conflicts and citizen participation are discussed, which have different, and sometimes opposing views, of the goals of participation. It is argued that the expectations of what can be achieved by citizen participation in the handling of siting conflicts must be realistic. More specifically, the results of the case studies show that public consultation, which is the dominating form of citizen participation in Sweden, has some important limitations that must be acknowledged.

As more and more focus is put on the environmental questions and the request for cleaner transportation the demand on the vehicles increases. Especially the environmental request of the public transportation that is visible to the public and operates in the centre of the city. The demand on the buses used for public transportation will increase. The whole bus must be optimised, usually only the propulsion system is on focus. The optimisation does concern the vehicle and driveline not only the diesel engine that usually are used in those buses. As the driveline get more and more efficient, for instance by hybridisation and the passenger demand for comfort increases the auxiliary systems part of the energy use of the driveline increases. That will make the auxiliary system energy use more important. This study is focused on energy consumption by the auxiliary systems. In this study, detailed vehicle simulation in ADVIS0R, ADvanced VehIcle SimulatOR using MATLABTM/SIMULINKTM is used to investigate how to reduce the auxiliary sub system systems energy consumption. The simulation model that is used is verified by measurements on a Scania hybrid fuel cell concept bus. The methods used for reducing energy and fuel consumption are better control of the auxiliary system loading vehicle driveline and selection of more energy efficient components for the auxiliary systems. The control of the auxiliary systems involves: recover some of the kinetic energy when braking and switching off, if possible, the auxiliary system load in peak load mode.

Renewable energy systems are likely to become wide spread in the future due to environmental demands. As a consequence of the dispersed nature of renewable energy systems, this implies that there will be a distributed generation of electric power. Since most of the distributed electrical energy sources do not provide their electric power at line frequency and voltage, a DC bus is a useful common connection for several such sources. Due to the differences in output voltage among the sources, depending on both the type of source and their actual operating point, the sources are connected to the DC power system via power electronic converters. The intention behind the presented work is not to replace the existing AC power system, but to include local DC power systems. The AC and DC power systems are connected at some points in the network. The renewable energy sources are weak compared to the present hydro power and nuclear power plants, resulting in a need of power conditioning before the renewable energy is fed to the transmission lines. The benefit of such an approach is that power conditioning is applied on a central level, i.e. at the interface between the AC and DC power systems. Present DC transmission systems are discussed and investigated in simulations. Then, different methods for load sharing and voltage control are discussed. Especially, the voltage droop control scheme is examined thoroughly. Since the droop control method does not require any high-speed communication between sources and loads, this is considered the most suitable for DC distributed power systems. The voltage feed back design of the controller also results in a specification of the DC bus capacitors (equivalents to DC link capacitors of single converters) needed for filtering. If the converters in the DC distribution system are equipped with capacitors selected from this design criterion and if the DC bus impedance is neglected, the source converters share the total load equally in per uni