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  • 201.
    Holmberg, Jan
    et al.
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Kylsberg, Bengt
    Skokloster palace.
    Nelander, Per
    National Property Board.
    Improving the Energy efficiency in an 800 year old building2011Inngår i: International Conference on Energy Management in Cultural Heritage. Dubrovnik, Croatia. 6-8 April 2011, 2011Konferansepaper (Annet vitenskapelig)
  • 202.
    Holmberg, Jan
    et al.
    Högskolan på Gotland, Institutionen för kultur, energi och miljö.
    Kylsberg, Jan
    Skeri, Karin
    Damage Assessment of Objects of Art Correlated to Local Outdoor Climate During 300 Years2011Inngår i: Developments in Climate Control of Historic Buildings: Proceedings from the International Conference "Climatization of Historic Buildings, State of the Art" / [ed] Ralf Kilian, Tomáš Vyhlídal, Tor Broström, 2011, s. 77-85Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Skokloster castle, located north of Stockholm, has a rich collection of furnishing and decorative objects of various kinds dating back to the 17th century. The castle has no active climate control. The objective of this paper is to investigate the deterioration of selected objects correlated to outdoor climate over a 300 year period and to analyse the preservation strategy chosen at Skokloster. The results show that the selected object overall were in good condition, as the were selected to represent the whole collection this would indicate a major part of the collection has been relatively well preserved and that the strategy of “doing nothing” has been favourable.

  • 203.
    Holmin, Johan
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Levison, Emma
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Oehme, Sabina
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    The utilization of office spaces and its impact on energy use2015Independent thesis Basic level (degree of Bachelor), 10 poäng / 15 hpOppgave
    Abstract [en]

    The foundation STUNS is investigating a possible move of the Origo office with tenants to a new office space. The Origo office today has a low utilization rate which makes it interesting to investigate the possibility of having an office space based on the ratio of occupancy. The purpose of this study is to calculate a ratio of occupancy with the corresponding risk of overcrowding and estimate the energy reduction. When adapting the new office space to the optimal ratio of occupancy, three office design proposals will be created. With the chosen optimal ratio of occupancy at 68 percent, the risk of overcrowding spanned between 0.3 to 0.6 percent. All proposals based on the optimal ratio of occupancy lead to electricity and cost reductions. An open office design leads to an electricity reduction of 686 kWh and a cost reduction of 168 kSEK per month. An activity based workplace leads to an electricity reduction of 540 kWh and a cost reduction of 132 kSEK per month. An individual office design leads to an electricity reduction of 452 kWh and a cost reduction of 111 kSEK per month. A sensitivity analysis is made by altering input parameters. The analyzed parameters are the unique attending employees, the transition probabilities and the choice of risk of overcrowding. For optimal utilization an open office space is the best alternative because it requires least square meters based on the same ratio of occupancy and workspaces. But when considering more aspects about work habits, employees’ opinions and behaviour the optimal office design may need a different structure.

  • 204.
    Holmkvist, Carolin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Kvantifiering av osäkerheter i lyftkraftsmodellen2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    With today´s power uprates in BWR reactors the bundle lift force has become aproblem. The lift force is calculated using a best estimate approach and the resultfrom the calculation should pass the existing lift force margin. Lift force margin isdefined so that the lift force may not exceed 80 % of the fuel weight. The margin issupposed to cover all the uncertainties that exist in the lift force calculations.However, no uncertainty analysis has been conducted to quantify the uncertainties.

    In this report the uncertainties in the lift force model have been quantified. Each inputparameter to the lift force model which has been assumed to have an uncertainty isassigned a probability distribution. Through the Monte Carlo method and Wilk´smethod an uncertainty propagation has been performed at different points in thereactor´s power flow map. By using these two methods, uncertainty in input datahave been translated into uncertainty in output data. This study has investigated fuelfrom different companies. From the Monte Carlo and Wilk´s method the lift force hasbeen calculated at various probabilities. By using these results, a lift force margin hasbeen calculated for each fuel type and at various probabilities.

    The results from the uncertainty propagation shows that the current lift force margincorresponds to approximately 95 % probability that lift doesn´t occur for all fueltypes. By using the uncertainty propagation, a new way of calculation the lift forcemargin has been developed.

  • 205.
    Holmqvist, Marcus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Gunnteg, Marcus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Seepage, Solute transport and Strain-stress Analysis of Ashele Tailings Dams2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This master thesis has been conducted through cooperation between Elforsk, Uppsala University and Tsinghua University in Beijing. Ashele Tailings Dam, located in Haba Town, Xianjing Province, China, is designed and used for high sulphur tailings. Because of a new mineral separation technique, the dam is now also being filled with low sulphur tailings. Since the dam was not originally designed for the new tailings materials, the seepage and stress-strain analyses of the dam need to be re-evaluated and refined. The Ashele Ltd. is also planning on building a new dam to meet its growing need for tailings deposit capacity. This dam will be used for the new low sulphur tailings and a thorough analysis of the dam will have to be performed.The purpose of this thesis is to re-evaluate the analyses of the seepage and stress-strain in the old dam and to perform the same type of analyses on the newdam. Numerical analyses of the seepage, solute transport and strain-stress in the dam are performed, using the physical and mechanical properties of the tailings materials. It is shown, that the construction of the new tailings dam, will have a good effect on the seepage and therefore also solute transport. The results also show that theseepage, solute transport, stress and deformation are depending on the amount ofwater in the tailings pond and that a lower water level has a positive effect on all thestudied variables.

  • 206.
    Hong, Sanghyun
    et al.
    Univ Tasmania, Fac Sci Engn & Technol, Private Bag 55, Hobart, Tas 7001, Australia..
    Qvist, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Brook, Barry W.
    Univ Tasmania, Fac Sci Engn & Technol, Private Bag 55, Hobart, Tas 7001, Australia..
    Economic and environmental costs of replacing nuclear fission with solar and wind energy in Sweden2018Inngår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 112, s. 56-66Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Nuclear power is facing an uncertain future in Sweden due to political directives that are seeking to phase out this energy source over coming decades. Here we examine the environmental and economic costs of hypothetical future renewable-energy-focused cases compared with the current nuclear and hydroelectricity-centred mix in Sweden. We show that if wind and photovoltaics replace entire nuclear power while maintaining the current level of dispatchable backup capacity including hydroelectric power and peak gas power, 154 GW of wind power will be required and will generate 427.1 TWh (compared with the actual demand of 143.7 TWh) to reliably meet demand each hour of the year. As a consequence, the annual spending on electricity systems will be five times higher than the status quo. Increasing dispatchable power, increasing transmission capacities to other countries, and generating electricity from combined heat and power plants even when there is no heat demand, will together reduce the required capacities of wind and solar photovoltaic by half, but it will double the greenhouse gas emissions during the combustion process. In conclusion, our economic and greenhouse-gas emissions analyses demonstrate that replacing nuclear power with renewables will be neither economic nor environmentally friendly with regards to the climate.

  • 207.
    Hong, Yue
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Eriksson, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Castellucci, Valeria
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Boström, Cecilia
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Waters, Rafael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Linear generator-based wave energy converter model with experimental verification and three loading strategies2016Inngår i: IET Renewable Power Generation, ISSN 1752-1416, E-ISSN 1752-1424, Vol. 10, nr 3, s. 349-359Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Within the Lysekil wave energy research project at the Swedish west coast, more than ten Wave Energy Converters (WECs) prototypes have been developed and installed in an ocean based test site. Since 2006 various experiments have been conducted and the generated electricity was delivered to shore at a nearby island. While experiments are essential for the development of wave energy converters, theoretical studies and simulations are an important complement – not only in the search for advanced designs with higher efficiency, but also for improving the economic viability of the studied concepts. In this paper a WEC model is presented. The model consists of three subsystems: i) the hydrodynamic source, ii) the linear generator model, and iii) the electrical conversion system. After the validation with the experimental results at the research site, the generator model is connected to three passive load strategies – linear resistive load, passive rectification and resonance circuit. The paper focuses on analysing the operation of the model coupled with three load cases. The results prove that the WEC model correctly simulates the linear generator developed in the Lysekil Project. Moreover, the comparison among different load cases is made and discussed. The results gives an indication of the efficiency of energy production as well as the force ripples and resulting mechanical loads on the wave energy converters.

  • 208.
    Häger, Oskar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Ekonomiska och tekniska möjligheter med batterilager: En lönsamhetsstudie av batterilager i solcellsförsedda kontorsbyggnader2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [sv]

    The ability to store energy becomes even more important as the proportion of intermittent and local energy production increases. The growing electric car industry is dependent on batteries and because of this, battery storage technologies are emerging rapidly.

    This project analyses how a real estate company can take advantages of a battery storage installed in office buildings equipped with a photovoltaic system. The results are based on simulations on two test facilities where three saving opportunities were analysed. These opportunities are; peak shaving, transfer charge and store surplus from the photovoltaic system. A local battery storage combined with a smart control software can facilitate an opportunity for actors to capitalize on the varying electricity prices.

    This study shows that one of the main issues with battery storage is how to formulate a strategy around charge and discharge of the battery. The challenge is to find a balance between having enough energy stored to enable peak shaving and to be prepared to store potential surplus energy. The electricity surplus is generally higher during weekends due to less activity in office buildings, which means that a battery storage with higher capacity is required during weekends in comparison to workdays.

    This study’s net present value calculation over the time of 15 years, with a 5 % discount rate and assumed 3 % increase of electricity price and peak cost, indicates that the investment cost of a battery storage needs to decrease by 50 % to become financially sustainable.

  • 209.
    Hävermark, Ulf
    Institutionen för energi och teknik, SLU.
    Processintern metananrikning: energikartläggning och efterbehandling av svepgas2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Small scale biogas plants (max digester volume 1000 m3) in Sweden produced in average 1.26 GWh per plant in 2014. Most of the biogas was used for combined heat and power production. The relatively cheap electricity in Sweden makes this a low profit business. If the biogas is upgraded to vehicle fuel its value will increase. However, upgrading biogas with conventional methods is costly, and for small scale biogas plants this cost cannot be justified. Development of alternative upgrading methods is an option to decrease the cost of upgrading and making small scale vehicle fuel production a reality.

    In this master thesis the upgrading method known as in-situ methane enrichment was investigated. This method involves desorption of carbon dioxide in the sludge using a desorption chamber separated from the digester. Air is blown through the sludge for desorption of carbon dioxide. Subsequently, the sludge is pumped back to the digester. The aim was to perform an energy mapping on the enrichment facility installed at the biogas plant (260 m3) at Sötåsens naturbruksgymnasium. In addition, the possibility to absorb ammonium-nitrogen in the off-gas from the process using a scrubber was also investigated in laboratory-scale.

    The results showed that the upgrading facility lost large quantities of heat during operation. During the coldest circumstances using an air flow of 260 m3/h through the sludge, the heat loss was 495 kWh/day. The corresponding efficiency of carbon dioxide removal was 7.6 kWh/m3 removed carbon dioxide. With proper insulation and heat recovery, the facility has the potential to decrease the heat demand to ca 139 kWh/day, giving an efficiency of 2.3 kWh/m3 removed carbon dioxide. The electric efficiency was 1 kWh/m3 removedcarbon dioxide.

    The laboratory test of ammonium-nitrogen absorption indicated that the plant has a potential to absorb 59 – 275 kg nitrogen/year by installing a scrubber with a volume of 122 l. The economic benefits are small, but other values such as reduced ammonia pollution or heat recovery solutions using a scrubber should be considered.

  • 210.
    Håkansson, Daniel
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Palmquist, Marcus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Evaluation of Impacts from River Engineering Measures at Nanjing Reach of Yangtze River: An Application of Hydrodynamic Modelling and Sediment Transportation Simulations2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The demand of electric power has rapidly increased in China along with the financial development. High pollution rates have pushed the development towards more renewable energy generating alternatives. In recent years larger investments of hydropower- generated electricity have been to satisfy the increased demand.

    Hydropower can cause non-energy related problems when implemented in a large scale. In this project the Nanjing Reach of Yangtze River was investigated through a hydrodynamic and sediment transport perspective. Nanjing Reach consists of two river branches and the upstream construction of the Three Gorges Dam has caused an imbalance of sediment composition that leads to an increasing difference of the diversion ratio between the branches. This is causing a problematic navigational situation for larger vessels along the north branch.

    In this project non-submerged water diverting dykes were modelled using two-dimensional depth averaged finite element method to estimate the impact on the hydrodynamic and sediment transport conditions. The examination showed that engineering measures at the downstream part of the reach were more effective than structures at the front, when taking both

    hydrodynamic and the more long-term impacts from sediment transport into account. Although the results of the sediment transportation are uncertain, the long- term consequences with investigated engineering measures can be concluded to have negative impact on the sustainability of the reach, however short-term improvements can be achieved.

    Other factors such as stability, material use, economics and marine conditions were not treated in this project but are vital for a reliable solution. 

  • 211.
    Högström, Emil
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Industriell teknik.
    Falkenberg, Oskar
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Industriell teknik.
    Efterfrågeflexibilitet hos kunder: De nya funktionskraven på elmätare och deras inverkan på efterfrågeflexibilitet2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The electricity system will go through massive changes in the coming years. Smartgrids are becoming more popular. The phasing out of fossil fuels in electricity production in favour of renewable power sources will entail challenges. To handle these challenges, the Swedish Energy Markets Inspectorate (Ei) has identified demand side flexibility as a partial solution. Ei has presented new functionality demands on electricity meters, which aim at working for an increase of demand side flexibility. The aim of this report is to investigate how smart meters and the new functionality demands contribute in making customers become more active, along with how customers can be motivated to change their behaviour. The findings from this report show that the new demands do not directly lead to more demand side flexibility. Instead they enable other actors to develop services that could lead to customers contributing with demand side flexibility. In the energy sector, it is assumed that customers need to see an economic benefit in order to contribute with flexibility. This report finds that this is not entirely the case. Customers can be motivated by other things, such as protecting the environment. Important factors for customers are that they experience the same comfort as before, along with simplicity. Therefore, automatic steering is the preferable option which might entail the need for economic subsidies since investing in automatic systems will be economically notable. Once a considerable amount of customers are contributing with flexibility, social pressure might motivate remaining customers to do the same.

  • 212.
    Höök, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Depletion rate analysis of fields and regions: a methodological foundation2014Inngår i: Fuel, ISSN 0016-2361, E-ISSN 1873-7153, Vol. 121, nr 4, s. 95-108Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    This paper presents a comprehensive mathematical framework for depletion rate analysis and ties it to the physics of depletion. Theory was compared with empirical data from 1036 fields and a number of regions. Strong agreement between theory and practice was found, indicating that the framework is plausible. Both single fields and entire regions exhibit similar depletion rate patterns, showing the generality of the approach. The maximum depletion rates for fields were found to be well described by a Weibull distribution.

    Depletion rates were also found to strongly correlate with decline rates. In particular, the depletion rate at peak was shown to be useful for predicting the future decline rate. Studies of regions indicate that a depletion rate of remaining recoverable resources in the range of 2–3% is consistent with historical experience. This agrees well with earlier “peak oil” forecasts and indicates that they rest on a solid scientific ground. 

  • 213.
    Höök, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Globala energisystem.
    Future coal production outlooks in the IPCC Emission Scenarios: Are they plausible?2011Inngår i: Energy and Environment, ISSN 0958-305X, E-ISSN 2048-4070, Vol. 22, nr 7, s. 837-858Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Anthropogenic climate change caused by CO2 emissions is strongly linked to the future energy production, specifically coal. The Special Report on Emission Scenarios (SRES) contains 40 scenarios for future fossil fuel production and is used by the IPCC to assess future climate change. This study examines the SRES coal production outlooks. Fundamental assumptions regarding coal availability and production in SRES was also compared with recent studies on reasonable future production outlooks. It was found that SRES puts unreasonable expectation on just a few countries. Is it reasonable to expect that China, already accounting for 46% of the global output, would increase their production by a factor of 8 over the next 90 years, as implied by certain SRES scenarios? It is concluded that SRES is underpinned by a paradigm of perpetual growth and technological optimism as well as old and outdated resource estimates. This has resulted in overoptimistic production outlooks.

  • 214.
    Höök, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Naturresurser och hållbar utveckling.
    Mapping Chinese Supply2018Inngår i: Nature Energy, ISSN 0028-212X, E-ISSN 2213-0217, Vol. 3, nr 3, s. 166-167Artikkel i tidsskrift (Annet vitenskapelig)
    Abstract [en]

    Documenting the emissions and net energy of a crude supply could be essential to meeting national emission and energy security targets. Using data from hundreds of fields worldwide, a well-to-refinery study presents a high-granularity profile of China’s crude oil supply in terms of emissions and energy return on input.

  • 215.
    Höök, Mikael
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Davidsson, Simon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Johansson, Sheshti
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Tang, Xu
    China University of Petroleum - Beijing.
    Decline and depletion rates of oil production: a comprehensive investigation2014Inngår i: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 372, nr 2006, s. 0120448-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Two of the most fundamental concepts in the current debate about future oil supply are oil field decline rates and depletion rates. These concepts are related, but not identical. This paper clarifies the definitions of these concepts, summarises the underlying theory and empirically estimates decline and depletion rates for different categories of oil field. A database of 880 post-peak fields is analysed to determine typical depletion levels, depletion rates, and decline rates. This demonstrates that the size of oil fields has a significant influence on decline and depletion rates, with generally high values for small fields and comparatively low values for larger fields. These empirical findings have important implications for oil supply forecasting.

  • 216.
    Höök, Mikael
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Dean, Fantazzini
    Moscow State University.
    André, Angelantoni
    Post Peak Living.
    Simon, Snowden
    University of Liverpool.
    Coal-to-Liquids: viability as a peak oil mitigation strategy2012Inngår i: Twenty Ninth Annual International Pittsburgh Coal Conference, 2012Konferansepaper (Fagfellevurdert)
    Abstract [en]

    Converting coal to a liquid, commonly known as coal-to-liquids (CTL), can supply liquid fuels and has been successfully used in several countries, particularly in South Africa. However, it has not become a major contributor to the global oil supply. Increasing awareness of the scarcity of oil and rising oil prices has increased the interest in coal liquefaction. This paper surveys CTL technology, economics and environmental performance. Understanding the fundamental aspects of coal liquefaction technologies is vital for planning and policy-making since future CTL production will be integrated in a much larger global energy and liquid fuel production system.

    The economic analysis shows that many CTL studies assume conditions that are optimistic at best. In addition, the strong risk for a CTL plant to become a financial black hole is highlighted. This helps to explain why China has recently slowed down the development of its CTL program.

    The technical analysis investigates the coal consumption of CTL. Generally, a yield of between 1–2 barrels/ton coal can be achieved while the technical limit seems to be 3 barrels/ton coal. This puts a strict limit on future CTL capacity imposed by future coal production, regardless of other factors such as economic viability, emissions or environmental concern. For example, assuming that 10% of world coal production can be diverted to CTL, the contribution to the liquid fuel supply will be limited to only a few million barrels per day (Mb/d). This prevents CTL from becoming a viable mitigation plan for liquid fuel shortage on a global scale.

    However, it is still possible for individual nations to derive a significant share of their fuel supply from CTL but those nations must also have access to equally significant coal production capacity. It is unrealistic to claim that CTL provides a feasible solution to liquid fuels shortages created by peak oil. At best, it can be only a minor contributor and must be combined with other strategies to ensure future liquid fuel supply.

  • 217.
    Höök, Mikael
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Fantazzini, Dean
    Moscow School of Economics.
    Angelantoni, André
    Post Peak Living.
    Snowden, Simon
    Liverpool University.
    Hydrocarbon liquefaction: viability as a peak oil mitigation strategy2014Inngår i: Philosophical Transactions. Series A: Mathematical, physical, and engineering science, ISSN 1364-503X, E-ISSN 1471-2962, Vol. 372, nr 2006, s. 20120319-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Current world capacity of hydrocarbon liquefaction is around 400,000 barrels per day (kb/d), providing a marginal share of the global liquid fuel supply. This study performs a broad review of technical, economic, environmental, and supply chains issues related to coal-to-liquids (CTL) and gas-to-liquids (GTL). We find three issues predominate. First, significant amounts of coal and gas would be required to obtain anything more than a marginal production of liquids. Second, the economics of CTL plants are clearly prohibitive, but are better for GTL. Nevertheless, large scale GTL plants still require very high upfront costs, and for three real world GTL plants out of four, the final cost has been so far approximately three times that initially budgeted. Small scale GTL holds potential for associated gas. Third, CTL and GTL both incur significant environmental impacts, ranging from increased greenhouse gas emissions (in the case of CTL) to water contamination. Environmental concerns may significantly affect growth of these projects until adequate solutions are found.

  • 218.
    Höök, Mikael
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem. Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Naturresurser och hållbar utveckling.
    Li, Junchen
    China University of Petroleum - Beijing.
    Johansson, Kersti
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Snowden, Simon
    University of Liverpool.
    Growth rates of global energy systems and future outlooks2012Inngår i: Natural Resources Research, ISSN 1520-7439, E-ISSN 1573-8981, Vol. 21, nr 1, s. 23-41Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The world is interconnected and powered by a number of global energy systems using fossil, nuclear, or renewable energy. This study reviews historical time series of energy production and growth for various energy sources. It compiles a theoretical and empirical foundation for understanding the behaviour underlying global energy systems' growth. The most extreme growth rates are found in fossil fuels. The presence of scaling behaviour, i.e. proportionality between growth rate and size, is established. The findings are used to investigate the consistency of several long-range scenarios expecting rapid growth for future energy systems. The validity of such projections is questioned, based on past experience. Finally, it is found that even if new energy systems undergo a rapid "oil boom"-development - i.e. they mimic the most extreme historical events - their contribution to global energy supply by 2050 will be marginal.

  • 219.
    Höök, Mikael
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Tang, Xu
    China University of Petroleum - Beijing.
    Depletion of fossil fuels and anthropogenic climate change: a review2013Inngår i: Energy Policy, ISSN 0301-4215, E-ISSN 1873-6777, Vol. 52, s. 797-809Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    Future scenarios with significant anthropogenic climate change also display large increases in world production of fossil fuels, the principal CO2 emission source. Meanwhile, fossil fuel depletion has also been identified as a future challenge. This chapter reviews the connection between these two issues and concludes that limits to availability of fossil fuels will set a limit for mankind’s ability to affect the climate. However, this limit is unclear as various studies have reached quite different conclusions regarding future atmospheric CO2 concentrations caused by fossil fuel limitations.

    It is concluded that the current set of emission scenarios used by the IPCC and others is perforated by optimistic expectations on future fossil fuel production that are improbable or even unrealistic. The current situation, where climate models largely rely on emission scenarios detached from the reality of supply and its inherent problems is problematic. In fact, it may even mislead planners and politicians into making decisions that mitigate one problem but make the other one worse. It is important to understand that the fossil energy problem and the anthropogenic climate change problem are tightly connected and need to be treated as two interwoven challenges necessitating a holistic solution.

  • 220.
    Höök, Peter
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Utvärdering av beräkningskoden APROS för användning i inneslutningsanalyser2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    At Forsmark nuclear power plant the rather old-fashioned software COPTA is used in containment safety analysis. There exists a desire within the organisation to introduce a more modern software with ability to more detailed modeling and increased usability.

    The goal of this thesis was to evaluate the software APROS in containment safety analysis. APROS models describing one of the containments at Forsmark NPP have been developed. Two simulations of typical containment incidents, one of them a large pipe break, have been made where containment safety parameters such as pressure and temperature are studied. Results are analyzed and verified against results from corresponding COPTA models. The other part of the evaluation includes a listing of detected possibilities and limitations with APROS regarding containment modeling in general.

    Overall the developed APROS models show a good agreement with results from corresponding COPTA models. Observed differences can in most cases be explained by minor differences in model choices, mostly concerning flow patterns and heat transfer. APROS has many similarities with COPTA regarding the main calculation and modeling methods but APROS can in most cases be seen as the more sophisticated software with more possibilities regarding modeling complexity. The general conclusion is that APROS shows good potential to be used in containment safety analysis.

  • 221. Hüttler, W.
    et al.
    Hofer, G.
    Krempl, M.
    Trimmel, G.
    Wall, I.
    Decision support tool for the innovative and sustainable renovation of historic buildings (HISTool)2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 226-235Konferansepaper (Fagfellevurdert)
  • 222. Ioakeimidis, Christos
    et al.
    Polatidis, Heracles
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Haralambopoulos, Dias
    Use of Renewable Energy in Aquaculture: An Energy Audit case-study analysis2013Inngår i: Global NEST. International Journal, ISSN 1108-4006Artikkel i tidsskrift (Fagfellevurdert)
  • 223.
    Jacobsson, Jesper
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi.
    Photoelectrochemical water splitting: an idea heading towards obsolescence?2018Inngår i: Energy & Environmental Science, ISSN 1754-5692, E-ISSN 1754-5706, Vol. 11, nr 8, s. 1977-1979Artikkel, forskningsoversikt (Fagfellevurdert)
    Abstract [en]

    The production of hydrogen from water and sunlight is a way to address the intermittency in renewable energy production, while simultaneously generating a versatile fuel and a valuable chemical feedstock. Photoelectrochemical water splitting is one possible approach to accomplish this that has been researched since the early seventies. It has for a long time held the promise of having the potential to become the best, cheapest, and most efficient way to convert solar energy into chemical energy in the form of hydrogen, but in this paper, I argue that the time window where this could have happened has now come to an end. With the rapid development of both PV-technology and earth-abundant electrocatalysis, it will be tremendously difficult, even in the best-case scenario, for a classical photoelectrochemical water splitting device to compete with what PV-driven electrolysers can already do today. This is an insight that should influence the future of solar fuel research.

  • 224.
    Jacobsson, T. Jesper
    et al.
    Univ Cambridge, Dept Chem, Lensfield Rd, Cambridge CB2 1EW, England; Ecole Polytech Fed Lausanne, Lab Photomol Sci, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland.
    Correa-Baena, Juan-Pablo
    Ecole Polytech Fed Lausanne, Lab Photomol Sci, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland.
    Anaraki, Elham Halvani
    Ecole Polytech Fed Lausanne, Lab Photomol Sci, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland;Isfahan Univ Technol, Dept Mat Engn, Esfahan 8415683111, Iran.
    Philippe, Bertrand
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Stranks, Samuel D.
    MIT, Elect Res Lab, 77 Massachusetts Ave, Cambridge, MA 02139 USA;] Cavendish Lab, JJ Thomson Ave, Cambridge CB3 0HE, England.
    Bouduban, Marine E. F.
    Ecole Polytech Fed Lausanne, Photochem Dynam Grp, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland.
    Tress, Wolfgang
    Ecole Polytech Fed Lausanne, Lab Photon & Interfaces, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland.
    Schenk, Kurt
    Ecole Polytech Fed Lausanne, CH-1015 Lausanne, Switzerland.
    Teuscher, Joël
    Ecole Polytech Fed Lausanne, Photochem Dynam Grp, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland.
    Moser, Jacques
    Ecole Polytech Fed Lausanne, Photochem Dynam Grp, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland.
    Rensmo, Håkan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Molekyl- och kondenserade materiens fysik.
    Hagfeldt, Anders
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Kemiska sektionen, Institutionen för kemi - Ångström, Fysikalisk kemi. Ecole Polytech Fed Lausanne, Lab Photomol Sci, Inst Chem Sci & Engn, CH-1015 Lausanne, Switzerland.
    Unreacted PbI2 as a Double-Edged Sword for Enhancing the Performance of Perovskite Solar Cells2016Inngår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 138, nr 32, s. 10331-10343Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Lead halide perovskites have over the past few years attracted considerable interest as photo absorbers in PV applications with record efficiencies now reaching 22%. It has recently been found that not only the composition but also the precise stoichiometry is important for the device performance. Recent reports have, for example, demonstrated small amount of PbI2 in the perovskite films to be beneficial for the overall performance of both the standard perovskite, CH3NH3PbI3, as well as for the mixed perovskites (CH3NH3)(x)-(CH(NH2)(2))((1x))PbBryI(3y). In this work a broad range of characterization techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), photo electron spectroscopy (PES), transient absorption spectroscopy (TAS), UVvis, electroluminescence (EL), photoluminescence (PL), and confocal PL mapping have been used to further understand the importance of remnant PbI2 in perovskite solar cells. Our best devices were over 18% efficient, and had in line with previous results a small amount of excess PbI2. For the PbI2-deficient samples, the photocurrent dropped, which could be attributed to accumulation of organic species at the grain boundaries, low charge carrier mobility, and decreased electron injection into the TiO2. The PbI2-deficient compositions did, however, also have advantages. The record V-oc was as high as 1.20 V and was found in PbI2-deficient samples. This was correlated with high crystal quality, longer charge carrier lifetimes, and high PL yields and was rationalized as a consequence of the dynamics of the perovskite formation. We further found the ion migration to be obstructed in the PbI2-deficient samples, which decreased the JV hysteresis and increased the photostability. PbI2-deficient synthesis conditions can thus be used to deposit perovskites with excellent crystal quality but with the downside of grain boundaries enriched in organic species, which act as a barrier toward current transport. Exploring ways to tune the synthesis conditions to give the high crystal quality obtained under PbI2-poor condition while maintaining the favorable grain boundary characteristics obtained under PbI2-rich conditions would thus be a strategy toward more efficiency devices.

  • 225.
    Jakobsson, Kristofer
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Globala energisystem.
    Söderbergh, Bengt
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Globala energisystem.
    Snowden, Simon
    University of Liverpool Management School.
    Li, Chuan-Zhong
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Samhällsvetenskapliga fakulteten, Nationalekonomiska institutionen.
    Aleklett, Kjell
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Globala energisystem.
    Oil exploration and perceptions of scarcity: The fallacy of early success2012Inngår i: Energy Economics, ISSN 0140-9883, E-ISSN 1873-6181, Vol. 34, nr 4, s. 1226-1233Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    It has been suggested that oil exploration may lead to false perceptions of decreasing scarcity. We perform a simulation of the exploration process using Bayesian updating. The approach enables us to isolate the information effect on the success rate and also to quantify the subjective expectation of the total resource size. The area under exploration consists of a number of regions which may differ in their oil content. Exploration is performed with the goal to maximize the expected success rate. The resulting information about the distribution of oil and the total resource size is assumed public knowledge. A number of scenarios with variations in the dimensions of the area under exploration, the oil distribution and initial beliefs are considered. The results indicate that the information effect on the success rate is significant but brief — it might have a considerable impact on price but is an unlikely mechanism behind a long-term declining price trend. However, the information effect on expectations is gradual and persistent. Since exploration is performed in regions where the expected success rate is the highest, the historical success rate will not be representative of the area as a whole. An explorer will tend to overestimate the total resource size, thereby suggesting an alternative mechanism for false perceptions of decreasing scarcity, a mechanism that could be called the “fallacy of early success”.

  • 226.
    Jason, Hou
    et al.
    Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA.
    Qvist, Staffan
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi, Tillämpad kärnfysik.
    Kellogg, Roger
    Argonne Natl Lab, Nucl Engn Div, 9700 S Cass Ave, Argonne, IL 60439 USA.
    Greenspan, Ehud
    Univ Calif Berkeley, Dept Nucl Engn, Berkeley, CA 94720 USA.
    3D in-core fuel management optimization for breed-and-burn reactors2016Inngår i: Progress in nuclear energy (New series), ISSN 0149-1970, E-ISSN 1878-4224, Vol. 88, s. 58-74Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Breed-and-burn (B&B) reactors are a special class of fast reactors that are designed to utilize low grade fuel such as depleted uranium without fuel reprocessing. One of the most challenging practical design feasibility issues faced by B&B reactors is the high level of radiation damage their fuel cladding has to withstand in order to sustain the B&B mode of operation more than twice the maximum radiation damage cladding materials were exposed to so far in fast reactors. This study explores the possibility of reducing the minimum required peak radiation damage by employment of 3-dimensional (3D) fuel shuffling that enables a significant reduction in the peak-to-average axial burnup, that is, more uniform fuel utilization. A new conceptual design of a B&B core made of axially segmented fuel assemblies was adopted to facilitate the 3D shuffling. Also developed is a Simulated Annealing (SA) algorithm to automate the search for the optimal 3D shuffling pattern (SP). The primary objective of the SA optimization is to minimize the peak radiation damage while its secondary objective is to minimize the burnup reactivity swing, radial power peaking factor and maximum change of fuel assembly power over the cycle. Also studied is the sensitivity of the 3D shuffled core performance to the number of axially stacked subassemblies, core height and power level.

    It was found that compared with the optimal 2-dimensional (2D) shuffled core, the optimal 3D shuffled B&B core made of four 70 cm long axially stacked sub-assemblies and 12 radial shuffling batches offers a 1/3 reduction of the peak radiation damage level from 534 down to 351 displacements per atom (dpa), along with a 45% increase in the average fuel discharge burnup, and hence, the depleted uranium utilization, while satisfying all major neutronics and thermal-hydraulics design constraints. For the same peak dpa level, the 3D shuffling offers more than double the uranium utilization and the cycle length relative to 2D shuffling. The minimum peak radiation damage is increased to 360 or to 403 dpa if the core is made of, respectively, three - 70 cm or two - 140 cm long axially stacked subassemblies. Reducing the length of the subassemblies of B&B cores made of three-segment assemblies from 70 cm to 60 or 50 cm results in an increase in the peak radiation damage from 360 dpa to, respectively, 368 and 397 dpa.

  • 227.
    Jianliang, Wang
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem. China University of Petroleum - Beijing.
    Davidsson, Simon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Höök, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Lianyong, Feng
    Chinese coal supply and future production outlooks2013Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 60, s. 204-214Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    China's energy supply is dominated by coal, making projections of future coal production in China important. Recent forecasts suggest that Chinese coal production may reach a peak in 2010–2039 but with widely differing peak production levels. The estimated URR (ultimately recoverable resources) influence these projections significantly, however, widely different URR-values were used due to poor understanding of the various Chinese coal classification schemes. To mitigate these shortcomings, a comprehensive investigation of this system and an analysis of the historical evaluation of resources and reporting issues are performed. A more plausible URR is derived, which indicates that many analysts underestimate volumes available for exploitation. Projections based on the updated URR using a modified curve-fitting model indicate that Chinese coal production could peak as early as 2024 at a maximum annual production of 4.1 Gt. By considering other potential constraints, it can be concluded that peak coal in China appears inevitable and immediate. This event can be expected to have significant impact on the Chinese economy, energy strategies and GHG (greenhouse gas) emissions reduction strategies.

  • 228.
    Jin, Peng
    et al.
    College of Shipbuilding Engineering, Harbin Engineering University, Harbin, 150001, China .
    Zhou, Binzhen
    College of Shipbuilding Engineering, Harbin Engineering University, Harbin, 150001, China; Department of Engineering Science, University of Oxford, Oxford, OX1 3PJ, UK.
    Göteman, Malin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Chen, Zhongfei
    College of Shipbuilding Engineering, Harbin Engineering University, Harbin, 150001, China.
    Zhang, Liang
    College of Shipbuilding Engineering, Harbin Engineering University, Harbin, 150001, China.
    Performance optimization of a coaxial-cylinder wave energy converter2019Inngår i: Energy, ISSN 0360-5442, E-ISSN 1873-6785, Vol. 174, s. 450-459Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    To achieve a wider frequency range where the device has a larger capture width ratio, the performance of a heaving coaxial-cylinder wave energy converter is optimized through actively controlled generator damping and stiffness using a linear frequency domain model. The generator power take-off system is modeled as a damping-spring system, and the numerical model is validated against published results. The coupled dynamics of a two-body model is analyzed to search for the optimal generator damping and stiffness leading to maximal capture width ratio. The optimization process, which can be decoupled into two independent steps, leads to an improved performance of the device, with increased frequency bandwidth and better capture width ratio. The effects of water depth, mooring stiffness, and the dimensions of the WEC on the capture width ratio are also studied, and parameter values are identified which correspond to optimal performance of the device.

  • 229.
    Johansson, Gustav
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Naturresurser och hållbar utveckling.
    Kyla i Nyköping och Motala: Kartläggning av kylapotential för Vattenfall Värm2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Swedish energy company Vattenfall is currently the owner of the district heatingsystems in Nyköping and Motala. To be able to also offer cooling solutions tocustomers are becoming more and more important. This report describes the resultsof an investigation of the cooling market in the two cities and the potential needs forcooling today and in the coming 20 years. The total potential for the coming 20 yearsis estimated to be roughly 17 MW for Nyköping and 9 MW for Motala.Two possible district cooling systems for each of the two city centers was modeledand a comparison was made between different cooling techniques namely absorptionand compressor chillers.Absorption chillers driven with district heating during the summer is one way ofincreasing the load in a combined heat and power plant and thereby the possibleelectricity generation. The cost of heat production must be low for absorption chillerto be able to compete as an alternative. The cost for the increased heat load becauseof absorption chillers was simulated with results showing a cost of 34/MWh kr inNyköping and 143 kr/MWh in Motala for the two district cooling cases.Investment calculation showed that neither of the systems in the two cities areprofitable with a required rate of return of 7 %.

  • 230.
    Johansson, Hampus
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Hållbar energiförsörjning inom Bertegruppen AB: Tekniska och marknadsmässiga förutsättningar för solcellsinvesteringar inom koncernen2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis was conducted to study Bertegruppens vision of being a business group self-sufficient on electrical energy. The scope was to investigate the potential of the vision being realized in a near future by adding solar energy to the existing energy production mix.

    Examinations of the energy need and the consumption pattern at the different companies were made by studying hourly data from the electricity supplier. Future energy need was determined during interviews and study visits, where potential areas for solar modules also were identified. Global solar radiation data was collected fromthe STRÅNG model, provided by the Swedish Meteorological and Hydrological Institute. These data were inserted to the micro power simulation tool HOMER ENERGY, along with solar module parameters from a solar energy installer Bertegruppen has initiated discussions with. The simulations resulted in potential solar energy production for a maximized and an adapted case for each company. In the adapted case, the implications from the Swedish solar energy market were considered while in the maximized case they were not. The simulation output data were then processed in the computational tool MATLAB, along with the hourly data over the electrical energy consumption at each company. At last economical calculations were carried out for the maximized and adapted case for each company, based on the Levelized Cost of Energy method.

    By adapting the maximized solar cell systems at each company, expand the hydropower station according to the plans, add diary-residues from Sia Glass to the biogas plant and account for the electrical energy bought from other hydropower stations in Suseån within the guarantees of origin system, Bertegruppen would produce 50.8 percent of their electrical energy need in 2021. For the adapted solarcell systems, the share would be 46.3 percent. The maximized solar cell systems resulted in a LCOE of 0.522 kr/kWh for Bertegruppen at a present value of 1 934 tkr.The LCOE for the adapted solar cell systems would be 0.529 kr/kWh at a presentvalue of 823 tkr.

  • 231.
    Johansson, Jim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Utilizing Energy Storage Applied on Floating Wind Turbine Economics Using a Spot-Price Based Algorithm2017Independent thesis Advanced level (degree of Master (One Year)), 10 poäng / 15 hpOppgave
    Abstract [en]

    In this paper, a new algorithm for utilizing energy storage is proposed and applied on floating wind turbine economics. The proposed algorithm’s decision making on storing energy or selling electricity onto the grid is based on the electricity price, which makes it unique and different from similar algorithms. From the literature review, it was concluded Ocean Renewable Energy Storage to be most suitable with the Spar-Type and Semi-Submersible floating wind turbine to which the paper is based upon. The objective of this paper is to find the suitable ratio of energy storage versus wind farm, find the product of increase in wholesale, and evaluate whether the proposed method makes the hybrid economically sound. The algorithm was applied on spot-price data from Denmark due to its large share of wind energy with wind data from off the coast of Morro Bay in California, USA. Additionally, a sensitivity analysis is applied to evaluate to energy storage cost impact as well as evaluate the algorithm by lowering the required energy storage size.

     

    Using the algorithm, the wind farm must account for nine days’ worth of energy production with a product of energy storage versus wind farm ratio of 1.42. The wholesale price increased with 11.9-21.5% for the four years studied, however, all financial results favored not utilizing energy storage. By the results derived from the sensitivity analysis, it was concluded that with future cost reductions, the algorithm will still favor no energy storage. However, by fine tuning the algorithm to reduce the need for storage, positive financial result might be achievable. The key to achieve a profitable result seems to rely on minimizing the need for energy storage, to which the proposed algorithm fail to achieve. Conclusively, spot-price decision-based energy storing is not economically sound.

  • 232. Johansson, P.
    et al.
    Donarelli, Anna
    Uppsala universitet, Humanistisk-samhällsvetenskapliga vetenskapsområdet, Historisk-filosofiska fakulteten, Konstvetenskapliga institutionen, Kulturvård.
    Strandberg, P.
    Performance of insulation materials for historic buildings: Case studies comparing a super insulation material and hemp-lime2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 80-88Konferansepaper (Fagfellevurdert)
  • 233.
    Johnsson, Malin
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Pilotinstallation av fast och fjärravläst nätstationsmätning: Identifiering av för- och nackdelar med nätstationsmätning, Mälarenergi Elnät AB2014Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Today’s electrical grid companies understand that better knowledge of and information about their grid can help realize a smart grid network. One way to gain better knowledge and information about the low voltage network is to install measuring equipment on the substation transformer´s secondary low voltage side that measures the low voltage network losses for that specific substation. By doing so, grid companies can, due to the calculation of the low voltage network losses, identify and address issues such as illegal power dissipation, unmeasured power outtakes, and unsatisfied technical documentation for the substations low voltage network.

    During 2012, Mälarenergi Elnät AB had a total electrical network loss (both medium and low voltage network losses included) of three to four percent of their total distributed electrical volume. Converting this energy volume into a monetary figure this accounts for a loss of around 30 million Swedish crowns. To address Mälarenergi Elnät AB’s issue about their low voltage network losses, Mälarenergi Elnät AB asked me to perform my civil engineering master thesis around this subject.

    Mälarenergi Elnät AB wanted me to perform measurements in five pre-existingsubstations. I had seven EDMI MK10A CT electrical meters for substation measurements installed in five pre-existing substations in the surrounding area of Västerås in order to investigate the potential costs and benefits of increased measurement in the low voltage network system. The total cost of my substation measurement installation reached 35 000 SEK or around 5 000 SEK per installed electrical meter.

    The calculated low voltage network losses from my measurements in the selected pre-existing substations showed that 75 % of the studied low voltage networks had losses in the range of zero to five percent. From the calculated results I also identified several benefits of measurements in pre-existing substations, including improved calculation of low voltage network losses, increased awareness of load levels so that maintenance could be more efficiently scheduled, and more accurate technical documentation, all of which can lead to increased customer satisfaction. The disadvantages of measurement in pre-existing substations that I identified during my master thesis study were the high installation cost of the meters and the increased demand on human resources during the implementation phase. Overall, my economic evaluation of the project showed that the investment was not cost effective, despite the acknowledged benefits of these substation measurements.

    The overall results suggest that Mälarenergi Elnät AB could benefit from installing meters in new substations, and in some existing substations where specific information about the low voltage network loss is needed for issues such as identifying suspicious illegal power dissipation or unmeasured power outtakes. The high installation cost for substation measurements are, in those cases, motivated by the fact that the substation measuring equipment costs are low compared to a whole new substation or compared to the fact of finding unmeasured outtakes, illegal powerdissipations etc.

  • 234.
    Jonsson Forsblad, Nils
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Evaluating the Potential for Floating Offshore Wind Power in Skagerrak: The Golden Triangle2016Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Wind power is a rapidly growing industry worldwide, both on- andoffshore. Most of the good locations onshore in continental Europeare in use today, which has prompted a move offshore in recentyears. Europe has by far the most offshore wind turbinesinstalled, mostly located in the North sea.The low hanging fruits are locations with relatively shallowwaters (up to 45-50 meters), a high and steady wind speed and isclose to grid connections onshore. Big parts of the North Sea aresuitable for this, but many places with good wind conditionsworldwide are too deep. The next step for the industry is to moveto these deeper waters, with the help of floating wind turbines.The first prototype floating turbines have been running for acouple of years, with even larger, albeit still pretty small, windfarms in the planning stage.This thesis looks on the possibility of building large floatingwind farms in the future, specifically in the eastern most part ofthe North Sea - Skagerrak. Several different factors andstakeholders have been mapped out and important factors such aswater depth, wind speed and seabed conditions considered to createfour different future scenarios. Each scenario has been evaluatedtechnically and Levelized Cost of Energy (LCOE) has beencalculated to be able to compare the different locations.Since the technology is very new and under development, theinitial costs are high. This gives the lower LCOE of 149 €/MWh.Many new developments are however expected in the years to come,which would lower the investment cost considerably, by up to 40%according to some sources. This would lower the LCOE to under 100€/MWh.It is however also found that these investments carry many otherpositive effects, such as developing a new carbon neutraltechnology in Scandinavia which could become a big exportworldwide. The social acceptance of bottom fixed foundationoffshore (close to shore) and onshore wind power is also falling,and this would also be a big plus for floating offshore wind as itcan be built so far offshore it can't be seen from land. BothSweden and Denmark have big power plants closing in the comingdecades, nuclear power in Sweden and coal fired power plants inDenmark. These need to be replaced either by import or by newcarbon neutral power production.

  • 235.
    Junchen, Li
    et al.
    China University of Petroleum.
    Xiucheng, Dong
    China University of Petroleum.
    Höök, Mikael
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper, Globala energisystem.
    Jian, Gao
    China University of Petroleum.
    Shiqun, Li
    Risk evaluation of technology innovation in Chinese oil and gas industry2013Inngår i: International Journal of Global Energy Issues, ISSN 0954-7118, E-ISSN 1741-5128, Vol. 36, nr 1, s. 1-12Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Oiland gas industries are technology intensive and appropriate risk evaluation isnecessary. The Chinese oil and gas industry is in the development phase, thusrisk assessments and mitigation is more important than pushing technologicalinnovation. This paper compiles research of other experts in the field andevaluates innovation risk by using a multi-hierarchy grey method. The resultshows that the technology innovation risk for Chinas oil and gas industry isrelatively high. Finally, this paper proposes some suitable measures that may decreaserisk levels.

  • 236. Kalamees, T.
    et al.
    Arumägi, E.
    Alev, Ü.
    Performance of interiorly insulated log wall: Experiences from Estonian cold climate conditions2018Inngår i: Conference Report: The 3rd International Conference on Energy Efficiency in Historic Buildings / [ed] Tor Broström, Lisa Nilsen and Susanna Carlsten, Uppsala University, 2018, s. 99-107Konferansepaper (Fagfellevurdert)
  • 237. Kall, Ann-Sofie
    et al.
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Det stora i det lilla och det lilla i det stora: Politik och teknik i omställningen av energisystemet2007Rapport (Annet vitenskapelig)
  • 238.
    Kamp, Sigrid
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets elektronik.
    Sveriges potential för elproduktion från takmonterade solceller: Teoretisk, teknisk och ekonomisk analys2013Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The Swedish potential of electricity production from roof mounted solar panels has been determined in three steps: accessing the existing roof top areas, simulating the amount of electricity solar panels can produce on these areas and finally analyzing how large the necessary economical change is to make the solar cells profitable.

    The total existing amount of roof top areas are 319 square kilometers and the area distribution follows the distribution of people. This leads to an installed power of 47,9 GW which are expected to produce 49,0 TWh electricity per year. If the quality of the electricity is prioritized the highest the power is reduced to 3,7 GW, generating 3,8 TWh yearly, but if the hosting capacity is calculated from Sweden’s total electricity need, the capacity is 42 TWh per year.

    Today, solar panels are not profitable in Sweden for houses, even though there is a subsidy of 35 % of the investment costs, discounted in 25 years. The profitability is calculated with a cost of capital of 5 %, a price on electricity of 1 SEK/kWh and an investment cost of 20 SEK/Wp. With a kept subsidy of 35 %, the price of electricity needs to rise 30 % to make the systems profitable for houses, and the corresponding increase without the subsidy is 95 %. Historically the subsidy has decreased as the costs of solar cells have decreased as well.

    For apartment buildings solar panels are profitable with the governmental subsidy if the solar systems are at least 3 kWp per house hold. The corresponding price increase without the subsidy is 60 %.

  • 239. Karlsson, Kristofer
    Restvärmetillförsel i Ludvikas Fjärrvärmesystem: Påverkan på befintlig värmeproduktion vid olika inkopplingsscenarier av 60°C restvärme2019Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Energy company Vattenfall AB has set an ambitious goal in trying to transform their business into a climate neutral and more resource effective company - all within thetime frame of one generation. Through the business concept “SamEnergi” within the heat sector, Vattenfall looks for district heating customers who are willing to sell heat at a price corresponding to Vattenfall’s own production cost. This report examines the change in ordinary heat production in the partially Vattenfall-owned district heating system in the city of Ludvika, Sweden, arising from the delivery of waste heat from a data center to the system. The data center delivers 1 MW heat at 60 degrees Celsius which is lower than the desired temperature in the district heating grid. The change in ordinary heat production is evaluated in four different scenarios where each scenario represents a way to connect the heat source to the district heating grid, so that the delivery temperature to the costumer is not affected. In two of the scenarios, the data center is placed on site of the main heat production units. For all four scenarios, the ability to deliver heat during normal annual fluctuations in flow and temperature in the district heating grid are assessed. Also, in one scenario the effecton a flue gas condenser is considered. The heat production for a normal year is then modelled and simulated using an optimization software called BoFiT, with and without the excess heat.

    The results show that the 1 MW excess heat is worth between 0,9 and 1,8 million SEK depending on how the heat is delivered. The lowest value of the excess heat source comes from the scenario requiring a heat pump. The other three scenarios yield similar savings on the ordinary production. The best scenario is when the waste heat is delivered together with the main production unit.

  • 240.
    Karlsson, Linda
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper.
    Distributed generation - the reality of a changing energy market: A market based evaluation and technical description of small wind power and photovoltaics in Sweden 2011Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    Renewable distributed generation such as wind power and photovoltaics are gaining popularity all over the world. The overall aim of this Master thesis was to gather experience and knowledge regarding small wind power and photovoltaic with both a market based evaluation and technical description. Methods used have been literature review, interviews with market participants, evaluation of a wind mill and a photovoltaic system simulation with PVsyst 5.41.

    It was found that the main common incentive today for the development and spread of small wind power and photovoltaics for market participants is the symbolic value. It was also discovered that the market situation is complicated for the producing consumer.

    The spread of small wind power and PV today are a few per mille of a future potential, where politics largely control development and spread of small-scale solutions. The market is unclear and solutions around net charge is still an ongoing debate. Majority of the interviewed persons believes more in PV than in small wind power due to facts such as wind power is size-dependent and not optimal to build in urban areas.

    Results show that power quality issues are dependent on the network system as a whole and are often a matter of cost and can be prevented with different technical solutions. One conclusion was that bidirectional power flow increase complexity of problems around protection. Major energy companies are involved in projects to gather knowledge how to deal with DG both in technical aspects and how to deal with customers practically. 

  • 241.
    Karlsson, Linus
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Linderholm Jönsson, Thomas
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Fysiska sektionen, Institutionen för fysik och astronomi.
    Pre-feasibility Study of a Waste to Energy Plant in Chisinau, Moldova2012Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    The thesis outlined in this report has been done as a sub-project in cooperation between the municipalities Borlänge in Sweden and Chisinau in Moldova. The project aimed to explore the region's economic and environmental opportunities for waste incineration with energy recovery, also known as Waste to Energy.

    At present, the solution to the waste situation is unmonitored landfills with smaller sorting operations. Environmentally, this is a poor solution and although there are plans for change, no specific strategy has been presented. Another important issue is Moldova's dependence on foreign produced energy. The country's energy system is dependent on imported natural gas, and only a small part of the country's electrical energy is produced domestically. What makes the waste to energy so interesting for this region is that it contributes to an improvement in both of these issues by using the waste as fuel to reduce energy dependency.

    The study has been done without specific waste composition data for the Chisinau region. With this in mind a dynamic model in several steps has been made, designed to obtain new results depending on what waste composition is specified.

    The results of this study show that implementation of a waste incineration plant in the Chisinau energy system is economically and environmentally feasible, given the current conditions. The proposed plant is designed to annually handle 400,000 tonnes of waste, and would with the assumed waste composition deliver 560 GWh of district heat and 260 GWh of electric energy. This production provides an annual profit of 31.6 M €, which gives a positive net present value after the project amortization.

    Compared with the city's current solution with landfills and gas turbines, the project also provides a significant environmental improvement. During the plant's design lifetime, greenhouse gas emissions are 53.9%, and only 6.8% with the assumption that only a portion of the carbon content of the waste is of fossil origin.

  • 242. Karlsson, Magnus
    et al.
    Palm, Jenny
    Widén, Joakim
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Interdisciplinary Energy System Methodology: A compilation of research methods used in the Energy Systems Programme2011Rapport (Fagfellevurdert)
  • 243.
    Kerkvliet, Hans
    et al.
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Polatidis, Heracles
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Geovetenskapliga sektionen, Institutionen för geovetenskaper.
    Offshore wind farms’ decommissioning: a semi quantitativeMulti-Criteria Decision Aid framework2016Inngår i: Sustainable Energy Technologies and Assessments, ISSN 2213-1388, E-ISSN 2213-1396, Vol. 18, s. 69-79Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this paper a framework for identifying an appropriate decommissioning method for offshore windfarms is developed and applied. The whole approach is based on Multi-Criteria Decision Aid techniquesthat perform an integrated evaluation of three available wind farms’ decommissioning methods. A numberof evaluation criteria are established and assessed on a semi quantitative basis. The preference of adiverse audience of pertinent stakeholders can be also incorporated in the overall analysis. The frameworkis applied in a case-study in the Netherlands. Even though the stakeholders included were hypotheticaland their preferences only assumed the proposed overall approach, methodology andapplication could be useful for practitioners in the field.

  • 244. Kihlberg, Kristofer
    Integrering av Savonius-vindturbiner och solpaneler2018Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    This thesis considers the integration between Savonius wind turbines and photovoltaics to form a hybrid power system. Different integration techniques were studied to find the most suited technique and the necessary components. The hybrid system was then to be compared with a solar panel system of equal sizing to investigate whether it could compete in terms of production and profitability. A model of the hybrid systems was built in MATLAB Simulink to simulate the production of the systems. Simulations used SMHI measurement data over wind speeds, solar radiation and temperature, with data resolution of one hour for 2017. The Swedish electricity trading market was also studied to determine which guidelines and prices that apply when selling electricity to the grid. The investment costs for the systems were estimated to allow economic conclusions to be drawn. The result was that a hybrid system had a higher power delivery to the load but the total production was higher for the solar system. The hybrid system couldn’t compete with the profitability of the solar system in the studied case. Possible reasons for the result was that the wind resources at the tested location wasn’t enough and that the price for wind turbines was high. Conclusions was that the price of the turbines needs to decrease in order to make the hybrid system more competitive. For hybrid systems that contain wind turbines, it is important that the chosen site has good wind resources to take advantage of the potential of the turbines.

  • 245.
    Kilian, Ralf
    et al.
    Fraunhofer IBP.
    Vyhlídal, TomášCzech Technical University in Prague.Broström, TorHögskolan på Gotland, Institutionen för kultur, energi och miljö.
    Developments in Climate Control of Historic Buildings: Proceedings from the international conference "Climitization of Historic Buildings, State of the Art"2011Konferanseproceedings (Fagfellevurdert)
  • 246.
    Killinger, Sven
    et al.
    Australian National University.
    Bright, Jamie M
    Australian National University.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Engerer, Nicholas A
    Australian National University.
    A tuning routine to correct systematic influences in reference PV systems' power outputs2017Inngår i: Solar Energy, ISSN 0038-092X, E-ISSN 1471-1257, Vol. 157, s. 1082-1094Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Power output measurements from PV systems are subject to a wide variety of systematic external and internal influences, such as shading, soiling, degradation, module and inverter quality issues and other system-level losses. All of these influences upon PV power measurements make the use of PV power output datasets for higher-level analysis problematic, particularly in their use as reference PV systems for estimating the power of a regional portfolio. To address these issues, we present a three-step method. Firstly, a parameterisation and quality control of power measurements is performed, which also corrects for consistent inefficiencies by a loss factor LF. Secondly, the detection of systematic de-ratings affecting PV system power output differently for each time step of the day (predominantly due to shading) together with the implementation of a subsequent “re-rating” of the power output measurements in a process referred to as tuning. The pivotal element of this approach is a 30-day running 90th percentile of the clear-sky index for photovoltaics kpv and the computation of a daily de-rating profile. Lastly, high kpv related variance in the early morning and evening is detected and filtered. Whilst these three methods are independent of each other, we suggest applying them in combination following the same order as in our paper. Cross-validations of these methods demonstrate significant improvements to the PV power measurement profiles, particularly in their use as reference PV systems for upscaling approaches. The RMSE falls from 0.174 to 0.09 W/Wp, rRMSE from 46.5% to 21.9%, MAPE from 47.9% to 20.8% and the correlation r increases from 0.767 to 0.919. Hence, we report overall improvements to RMSE, rRMSE, MAPE and r by 48%, 53%, 57% and 20%, respectively

  • 247.
    Killinger, Sven
    et al.
    Australian National University.
    Bright, Jamie M
    Australian National University.
    Lingfors, David
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Fasta tillståndets fysik.
    Engerer, Nicholas A
    Australian National University.
    Towards a Tuning Method of PV Power Measurements to Balance Systematic Influences2017Inngår i: Proceedings of the ISES Solar World Congress 2017, AbuDhabi, United Arab Emirates, October 29 - November 2, 2017Konferansepaper (Fagfellevurdert)
    Abstract [en]

    With rapid deployment and penetration rates of residential photovoltaic (PV) systems in the distribution grid, there is growing need for accurate assessment of the real-time power generation for grid management and energy market operations. Many of these installed PV systems report their live power generation to online databases and can be used as references to estimate the power generation of neighbouring systems. Upscaling approaches have demonstrated their capability of using the data from these reference PV systems to estimate the power output of target PV systems that do not report their power generation data. However, there is an inherent issue with the representativeness of these reference PV systems power data, e.g. due to quality issues or system specific influences such as shading. Three methods were developed by the authors in earlier work: (1) a parametrisation of PV system metadata and quality control of the measured power, (2) a tuning routine that detects diurnal influences from shading and tunes the PV power in order to reach the expected generation without any shading. And (3) a method which eliminates high variances in kpv based upscaling. An extensive cross-validation with 308 systems in Canberra, Australia in this paper shows significant improvements as a direct result of the application of these three methods. Furthermore, we present the preliminary findings for developments in: the parametrisation of shaded/multi-azimuth reference PV systems, as well as a method to reduce inertia in the shade detection and tuning. Overall, we successfully improve the management of reference PV system power data for use in upscaling.

  • 248. Kindblom, Johan
    Utvärdering av behovsstyrt ventilationssystem i skolbyggnad: Energieffektivisering av ventilation2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

    New buildings today are built with great care and contain modern technology in order to minimize the energy cost and therefore also their upkeep. This project has tried to evaluate the effect of a smart demand-controlled ventilation system which measures the actual airflow demand and adjusts accordingly. By using exact data from a system inside a school and studying the building itself, an accurate model of the school was created. Using this model the demand-controlled system was compared to a conventional, constant flow, system. The results showed that the demand-controlled system reduced the specific energy consumption of the school by 34 % and that the systems components could be downsized to 70 % of the original size. This means that this kind of integration of control technology is a powerful tool to further increase the energy efficiency in buildings.

  • 249. Kjellgren, Peter
    et al.
    Spanoudakis, Nikolas
    Sales opportunities for solar collectors in industries: A market analysis of two different markets2017Independent thesis Advanced level (professional degree), 20 poäng / 30 hpOppgave
    Abstract [en]

     The intensifying environmental problems demand nations to take immediate action.

    The industry sector alone accounts for 54 % of the global energy demand (year

    2012) and the most common way for industries to get heat for its production, is still

    today by fossil-fuel boilers.

    One promising renewable energy source, which has great potential in replacing

    fossil-fuel boilers, is solar thermal energy. In order to meet all climate goals, the

    Paris agreement for example, renewable energy resources like solar thermal energy

    will become crucial.

    Absolicon Solar AB is a Swedish manufacturing company, whose main product is

    the solar collector T160. The T160 is a heat water producing collector, which is

    suitable for integrating in industrial heat water processes for temperatures up to 160

    °C. One of the challenges the company faces, is to find suitable markets and

    customers to sell its product to.

    Two promising markets that Absolicon want to explore and eventually enter are the

    Food and Beverage market in Spain, and the District Heating market in Denmark.

    This study aims to give Absolicon a better understanding of these two markets of

    interest, in order for Absolicon to enter and direct the right value proposition of its

    product to the right customers. Thus two qualitative market researches were

    conducted, one for each market. Based on the results of the market researches, two

    business strategies were proposed respectively. Finally, a comparative study is

    carried out and relative conclusions are drawn.

  • 250.
    Kjellin, Jon
    Uppsala universitet, Teknisk-naturvetenskapliga vetenskapsområdet, Tekniska sektionen, Institutionen för teknikvetenskaper, Elektricitetslära.
    Vertical Axis Wind Turbines: Electrical System and Experimental Results2012Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The wind power research at the division of Electricity at Uppsala University is aimed towards increased understanding of vertical axis wind turbines. The considered type of wind turbine is an H-rotor with a directly driven synchronous generator operating at variable speed. The experimental work presented in this thesis comprises investigation of three vertical axis wind turbines of different design and size. The electrical, control and measurement systems for the first 12 kW wind turbine have been designed and implemented. The second was a 10 kW wind turbine adapted to a telecom application. Both the 12 kW and the 10 kW were operated against dump loads. The third turbine was a 200 kW grid-connected wind turbine, where control and measurement systems have been implemented.

    Experimental results have shown that an all-electric control, substituting mechanical systems such as blade-pitch, is possible for this type of turbine. By controlling the rectified generator voltage, the rotational speed of the turbine is also controlled. An electrical start-up system has been built and verified. The power coefficient has been measured and the stall behaviour of this type of turbine has been examined. An optimum tip speed ratio control has been implemented and tested, with promising results. Use of the turbine to estimate the wind speed has been demonstrated. This has been used to get a faster regulation of the turbine compared to if an anemometer had been used.  

    Delarbeid
    1. Experimental results from a 12 kW vertical axis wind turbine with a direct driven PM synchronous generator
    Åpne denne publikasjonen i ny fane eller vindu >>Experimental results from a 12 kW vertical axis wind turbine with a direct driven PM synchronous generator
    2007 (engelsk)Konferansepaper, Publicerat paper (Annet vitenskapelig)
    Abstract [en]

    Experimental results from a three bladed vertical axis wind turbine with a direct driven PM synchronous generatorare presented. The H-rotor turbine, independent of wind direction, does not require any yaw mechanism.Furthermore, the variable speed, stall regulated turbine does not require pitch mechanism. The specifically designeddirectly driven generator eliminates the need for a gearbox. All electrical equipment, including generator, are placedon the ground. This reduces the weight that has to be supported by the structure and simplifies maintenance. Thus, theoverall strength of this concept is simplicity.The H-rotor has five meter long blades that are tapered at the tips. The aerodynamic torque is transferred to thegenerator via a 5.4 meter long drive shaft supported by a tower. A universal joint connects the drive shaft to thegenerator shaft, cancelling any transverse bending moments from the turbine on the generator. The generator acts as amotor to start up the turbine using a separate auxiliary winding. The turbine has a swept area of 30 m2 and is rated at12 kW in 12 m/s winds for 127 rpm.The turbine has been placed on a site where the wind resources have been extensively documented. The wind datarecord is more then ten years and includes data from various heights giving an accurate wind mapping of the area.The experimental aerodynamic power curve in turbulent wind conditions is presented. Considering the highlyturbulent wind conditions and the small size of the wind turbine these results are encouraging.

    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-97453 (URN)
    Konferanse
    EWEC 2007 - European Wind Energy Conference & Exhibition, Milan, Italy, May. 7-10, 2007
    Tilgjengelig fra: 2008-09-05 Laget: 2008-09-05 Sist oppdatert: 2018-05-30bibliografisk kontrollert
    2. Progress of control system and measurement techniques for a 12 kW vertical axis wind turbine
    Åpne denne publikasjonen i ny fane eller vindu >>Progress of control system and measurement techniques for a 12 kW vertical axis wind turbine
    Vise andre…
    2008 (engelsk)Konferansepaper, Publicerat paper (Fagfellevurdert)
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-97454 (URN)
    Konferanse
    ??
    Tilgjengelig fra: 2008-09-05 Laget: 2008-09-05 Sist oppdatert: 2016-04-12bibliografisk kontrollert
    3. Power coefficient measurement on a 12 kW straight bladed vertical axis wind turbine
    Åpne denne publikasjonen i ny fane eller vindu >>Power coefficient measurement on a 12 kW straight bladed vertical axis wind turbine
    Vise andre…
    2011 (engelsk)Inngår i: Renewable energy, ISSN 0960-1481, E-ISSN 1879-0682, Vol. 36, nr 11, s. 3050-3053Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A 12 kW vertical axis H-rotor type wind turbine has been designed and constructed at Uppsala University. A measurement campaign has been performed to collect data to calculate the power coefficient using the method of bins. The measurement was performed at different constant rotational speeds on the turbine during varying wind speeds to observe the power coefficients dependence on tip speed ratio. The power coefficient peaked at 0.29 for a tip speed ratio equal to 3.3.

    Emneord
    VAWT, H-rotor, Experimental, Measured, Cp
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-156579 (URN)10.1016/j.renene.2011.03.031 (DOI)000292441400035 ()
    Tilgjengelig fra: 2011-08-07 Laget: 2011-08-04 Sist oppdatert: 2018-05-30bibliografisk kontrollert
    4. Electrical Starter System for an H-Rotor Type VAWT with PM-Generator and Auxiliary Winding
    Åpne denne publikasjonen i ny fane eller vindu >>Electrical Starter System for an H-Rotor Type VAWT with PM-Generator and Auxiliary Winding
    2011 (engelsk)Inngår i: Wind Engineering: The International Journal of Wind Power, ISSN 0309-524X, E-ISSN 2048-402X, Vol. 35, nr 1, s. 85-92Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    In order to operate a modern wind turbine an effective start procedure is required. This article presents an electrical start for a VAWT which is shown to have advantages over an aerodynamic start. An electrical starter for a 12 kW VAWT has been designed and built. The starter is based on a six-step modulated inverter that is feedback-controlled by the rotor position. The inverter is connected to an auxiliary winding in the generator to separate the starter electronics from the main system. The system has been simulated and experimentally verified in the wind turbine setup.

    sted, utgiver, år, opplag, sider
    Multi Science Publishing, 2011
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-164210 (URN)10.1260/0309-524X.35.1.85 (DOI)
    Tilgjengelig fra: 2011-12-16 Laget: 2011-12-16 Sist oppdatert: 2018-05-30bibliografisk kontrollert
    5. Adapting a VAWT with PM generator to telecom applications
    Åpne denne publikasjonen i ny fane eller vindu >>Adapting a VAWT with PM generator to telecom applications
    Vise andre…
    2010 (engelsk)Inngår i: European Wind Energy Conference & Exhibition, Warsaw, Poland, 2010Konferansepaper, Publicerat paper (Fagfellevurdert)
    sted, utgiver, år, opplag, sider
    Warsaw, Poland: , 2010
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-142522 (URN)
    Konferanse
    European Wind Energy Conference & Exhibition
    Tilgjengelig fra: 2011-01-14 Laget: 2011-01-14 Sist oppdatert: 2018-05-30bibliografisk kontrollert
    6. Laboratory verification of system for grid connection of a 12 kW variable speed wind turbine with a permanent magnet synchronous generator
    Åpne denne publikasjonen i ny fane eller vindu >>Laboratory verification of system for grid connection of a 12 kW variable speed wind turbine with a permanent magnet synchronous generator
    2012 (engelsk)Inngår i: EWEA 2012 Annual Event, Copenhagen, Denmark, 2012, 2012Konferansepaper, Poster (with or without abstract) (Fagfellevurdert)
    Abstract [en]

    In this paper the first laboratory tests of the gridconnection system, connected to a resistiveload, for a vertical axis wind turbine (VAWT)with a permanent magnet generator arepresented. The system is based on a taptransformertopology with a voltage sourceinverter and an LCL-filter. The use of a taptransformer topology eliminates the need for aDC-DC converter to handle the variations inDC voltage. The harmonic content of thecurrents from experiments and simulationsperformed in Simulink using different taps onthe transformer are presented. The simulatedcurrents, fed to the resistive load, have a totalharmonic distortion (THD) of 0.5% to 0.9% forthe different taps. The experimental systemhas a current THD ranging from 1.8% to 2.8%.The difference is expected to be due tounbalances, delays and dead times in theexperimental set-up as the major THDcontribution is from harmonic orders below 11.The results show that an LCL filter can bedesigned to meet the demands on powerquality for grid connection of the system withall the taps of the tap transformer inaccordance with IEEE 519-1992.

    Emneord
    VAWT, Tap transformer, LCL-filter, voltage source inverter
    HSV kategori
    Forskningsprogram
    Teknisk fysik med inriktning mot elektricitetslära
    Identifikatorer
    urn:nbn:se:uu:diva-182434 (URN)
    Konferanse
    EWEA 2012 Annual Event, Copenhagen, Denmark, 2012
    Tilgjengelig fra: 2012-10-10 Laget: 2012-10-10 Sist oppdatert: 2018-05-30
    7. Electric control substituting pitch control for large wind turbines
    Åpne denne publikasjonen i ny fane eller vindu >>Electric control substituting pitch control for large wind turbines
    (engelsk)Artikkel i tidsskrift (Annet vitenskapelig) Submitted
    Emneord
    VAWT, Electrical, Control, Stall-regulation, Novel System
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-182436 (URN)
    Tilgjengelig fra: 2012-10-10 Laget: 2012-10-10 Sist oppdatert: 2018-05-30bibliografisk kontrollert
    8. Tip Speed ratio control of a 200 kW VAWT with synchronous generator and variable DC voltage
    Åpne denne publikasjonen i ny fane eller vindu >>Tip Speed ratio control of a 200 kW VAWT with synchronous generator and variable DC voltage
    2013 (engelsk)Inngår i: Energy Science & Engineering, ISSN 2050-0505, Vol. 1, nr 3, s. 135-143Artikkel i tidsskrift (Fagfellevurdert) Published
    Abstract [en]

    A novel control method for a fixed-pitch variable speed wind turbine is introduced and experimental results are presented. The measured absorbed power and rotational speed, together with a look-up table for the aerodynamic efficiency, are used to estimate the wind speed reaching the turbine as well as the tip speed ratio. Thereby, the control is independent on wind speed measurements and the wind turbine itself is used as an anemometer. Tip speed ratio control is implemented by comparing the estimated tip speed ratio to a reference value and adjusting the DC voltage level accordingly. Tip speed ratio control benefits from that the aerodynamic efficiency hardly varies with changing tip speed ratio when close to its optimum value. Experimental results from a 200 kW vertical axis wind turbine are presented. The voltage from the permanent magnet generator is passively rectified and the alternating DC voltage is then inverted, filtered, transformed, and grid connected. The estimated wind speed is compared with the measured wind speed. The absorbed power when tip speed ratio control has been implemented is shown. It is concluded that the presented control method works and some future improvements are discussed.

    Emneord
    control method, wind turbine, variable speed, H-rotor, experiments
    HSV kategori
    Identifikatorer
    urn:nbn:se:uu:diva-182437 (URN)10.1002/ese3.23 (DOI)000209695200004 ()
    Tilgjengelig fra: 2012-10-10 Laget: 2012-10-10 Sist oppdatert: 2018-05-30bibliografisk kontrollert
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