The Swedish electricity market was historically based on predictable and controllable power plants. The introduction variable renewable energy (VRE) sources in the market have led to less predictability and larger short-term variations in the generation profiles. These effects are compounded as the market share of VRE sources are increasing, and in Sweden’s case as the nuclear power plants are being phased out. Different metrics of value are calculated to shed light on the economic potential of new power sources. A not yet commonly used metric is the value factor of a technology, which represents the net increase or net decrease in revenue due to if the generation coincides with a high or low spot price of electricity. The thesis seeks to calculate the value factors and analyse their place within the northern European electricity market. In order to calculate the value factors and analysing them, the acquisition of datasets for varying market variables was required. The three sources of these datasets was for this thesis the ENTSO-E Transparency Platform, Nord Pool and Svenska kraftnät. These sources combined could supply datasets for market variables dating back to 2015 for Sweden and each country with an international connection with Sweden. This limits the scope of this analysis to 2015 - 2019 for Sweden and six other countries. The value factors were calculated for each Swedish electric price region divided into five categorical technologies, wind-, solar-, hydro-, nuclear- and heat power. The results from this only gave concrete results for two technologies. Wind power are shown to generally have a value factor below one and hydro power in the two northern regions have a value factor above one. This indicates that the market is saturated for wind power while in demand for hydro power from northern Sweden. Every other pair of technology and region vary as to not indicate whether the market is in demand of it or not. Analysing the association of variables was accomplished using a correlation study. Variables that consistently have a critical correlation factor, either linear or monotonic, are identified as associated variables. Out of these pairs of associated variables, the ones with a shared trend in either correlation or normalized regression with the trend of the appropriate value factor are identified as associated with the same value factor. This resulted in several associated variables for each value factor. Neither of these associations can by this methodology be identified as having a causal relation, it only displays correlations which could be incidental.

No description available.

The different life cycle phases of a building account for different amounts of environmental impact. During the past years the operational energy use in the building and construction sector has been reduced whilst relative and absolute embodied impact has increased. To reduce the overall environmental impact, design and material choices have to be optimized in relation to the energy use. The performed study aims to enhance more environmentally conscious decision-making in the building and construction sector by increasing awareness and knowledge about the environmental impact from life cycle phases of a building as well as different framework materials.  Three different designs of a typical Swedish multifamily building have been analyzed in the study. The case building has a concrete frame. The two alternative designs are based on the case building but has lower energy use. In addition, one of the alternative designs has a cross laminated timber frame. They were all analyzed in terms of embodied and operational environmental impact, expressed as carbon dioxide equivalents per heated area. A simulation model of the case building, calibrated with measured data, was implemented to calculate the operational energy use of the designs. The embodied emissions were calculated for the enclosing and load bearing structures.   The results show that both alternative designs have lower environmental impact than the original state of the case building. The construction with wooden frame has approximately 30 % less embodied emissions compared to the original state. Concrete has the largest share of the total embodied emissions and choosing product specific concrete can yield a reduction in embodied emissions of more than 9 %. Sensitivity analysis of the operational energy show a significant difference in the results depending on approach and system boundaries. A future scenario of operational energy result in increased relative contribution of embodied environmental impact. / En byggnads livscykelskeden har olika miljöpåverkan. I bygg- och anläggningssektorn har den operativa energianvändningen reducerats under de senaste åren. Den relativa och absoluta inbyggda påverkan har däremot ökat. För att minska den totala miljöpåverkan behöver byggnaders design och material optimeras i relation till energianvändningen. Den genomförda studien syftar till att öka miljömedvetet beslutsfattande i bygg- och anläggningssektorn genom att öka medvetenheten och kunskapen om miljöpåverkan från en byggnads olika livscykelskeden och om olika stommaterial.   I studien analyseras tre olika designer av ett typiskt svenskt flerbostadshus. Referenshuset har en betongstomme. De två alternativa designerna är baserade på referenshuset men har lägre operativ energianvändning. Den ena av de två alternativa designerna har dessutom en stomme i korslimmat trä. Samtliga utföranden analyserades i termer av inbyggd miljöpåverkan och operativa energianvändningens miljöpåverkan, uttryckt som koldioxidekvivalenter per uppvärmd area. En simuleringsmodell av referenshuset kalibrerad med mätdata implementerades för att beräkna de olika designernas operativa energianvändning. De inbyggda utsläppen beräknades för husets omslutande byggnadsdelar och bärande strukturer.  Resultaten visar att båda alternativa designer har lägre miljöpåverkan än originalutförandet av referenshuset. Konstruktionen med trästomme har cirka 30 % lägre inbyggda utsläpp jämfört med originalutförandet. De inbyggda utsläppen kommer till största del från betongen och ett produktspecifikt val av betong kan leda till en reduktion av dessa utsläpp med över 9 %. Känslighetsanalys av operativa fasen visar en signifikant skillnad beroende på vilken metod och vilka systemgränser som används. Ett framtidsscenario för operativa energianvändningen visar en ökad relativ påverkan från den inbyggda miljöpåverkan.

En byggnads värme- och varmvattenbehov utgör en stor del av dess totala energibehov. Vilket värmesystem som väljs blir därmed viktigt för att bli så ekonomiskt gynnsamt och miljömässigt bra som möjligt. Två vanliga värmekällor för flerbostadshus är bergvärme och fjärrvärme eftersom bergvärmen har en låg driftkostnad medans fjärrvärmen finns tillgänglig i de flesta städer samtidigt som båda systemen har låg miljöpåverkan. Syftet med studien är att koldioxidutsläpp på värmesystem ska vara så låga som möjligt till ett lågt pris. Målet med studien är därför att undersöka om ett kombinerat system bestående av bergvärme och fjärrvärme står sig ekonomiskt och miljömässigt bra i relation till ett bergvärmesystem eller ett fjärrvärmesystem på fyra platser i Sverige, Halmstad, Karlstad, Östersund och Luleå. Anledningarna till de olika städerna är dels att byggnadens värmebehov kommer att variera men även eftersom berget levererar olika mycket värmeeffekt. Beräkningarna sker för ett flerbostadshus med närmare 500 lägenheter ovanför ett uppvärmt garage med en total area på ungefär 26 500m2. Byggnadens energibehov och antalet värmepumpar som behövdes beräknades över ett år i simuleringsprogrammet HPC2 och används sedan för att bygga upp en LCC-kalkyl och göra miljöberäkningar i Excel. Resultatet från LCC-kalkylen visar att värmepumpsystemet är det mest ekonomiskt gynnsamma systemet följt av det kombinerade systemet och att fjärrvärmesystemet hade högst nuvärde i samtliga städer. Miljöpåverkan i Halmstad och Karlstad var lägst för värmepumpsystemet följt av det kombinerade systemet och även här hade fjärrvärmesystemet högst miljöpåverkan. I Östersund har det kombinerade systemet lägst miljöpåverkan, följt av värmepumpsystemet och högst har fjärrvärmesystemet. I Luleå har fjärrvärmesystemet lägst miljöpåverkan, följt av det kombinerade systemet och värmepumpsystemet. / A building's heating and warmwater needs make up a large part of its total energy needs and thus it becomes important which heating system is chosen to be economically favorable and environmentally sound as possible. Two common heat sources for multi-dwelling houses are geothermal heating and district heating, geothermal heating has a low operating cost while district heating is available in most Swedish cities, both having a low environmental impact. The aim of the study is to investigate whether a combined system consisting of geothermal heating and district heating is performing well both economically and environmentally in relation to a geothermal heating system or a district heating system at four locations in Sweden, Halmstad, Karlstad, Östersund and Luleå. The reason for evaluating the different cities is that the building's heating needs will vary but also because the mountain delivers different heating effect. The calculations are made over a multi-dwelling house with almost 500 apartments above a heated garage with a total area of approximately 26,500 m2. The building's energy needs, and the number of heat pumps needed were calculated over one year in the HPC2 simulation program and it was then used to build up an LCC calculation to make environmental and financial calculations in Excel. The result from the LCC calculation show that the heat pump system is the most economically favorable system followed by the combined system and that the district heating system had the highest value in all cities. The environmental impact in Halmstad and Karlstad was the lowest for the heat pump system followed by the combined system, and even here, the district heating system had the highest environmental impact. In Östersund, the combined system has the lowest environmental impact, followed by the heat pump system and the district heating system had the highest environmental impact. In Luleå, the district heating system has the lowest environmental impact, followed by the combined system and highest was the heat pump system.

No description available.

This master’s thesis is a contribution to the cross-disciplinary research project SitCit that addresses the issue of urban sustainable development. It aims to investigate how Information and Communication Technology (ICT) can be used to reduce the energy use and increase the energy demand flexibility in Stockholm’s Södermalm district. This study uses a bottom-up approach to model how ICT can change the energy use. The basis of the approach is the human activities that cause demand for services, delivered by different appliances, which in turn use energy to provide these services. The human activities are represented by Human Activity Systems (HAS) and the different appliances by Energy Usage Systems (EUS). A method for defining an energy system with a bottom-up approach was developed and used to build a conceptual model. Relevant ICT solutions were thereafter identified and described both technically and how they interact with the HAS, the EUS and the surroundings to change the energy use by means of automation, information and persuasion. It was also assessed how and when planning and implementation of ICT can be achieved, and who are the involved actors. The findings were compiled into an integrated qualitative model which was split into two parts, one that illustrates the interrelatedness of the different components expressed in terms of information flows, and one that shows who are the actors involved in the strategies to implement the various ICT solutions. Weaknesses in the bottom-up approach were identified and changes were suggested. The HAS should be split into human activities and what can be denoted “human” since most information flows due to ICT are not with the actual activities. The human can communicate through and with ICT. He or she can decide the activities and how much of them should be carried out, and is also the most important actor when it comes to the implementation of ICT. Furthermore, it was found that the coupling of HAS and EUS is weak, and time-use data and actual measurements on the energy use is therefore needed as input to a quantitative model. This study explains and illustrates how different ICT solutions work and how they can be implemented to change the energy use in an urban area. Together with the improvements in the bottom-up approach, and the methodological discussion, it can be used as groundwork for a quantitative model, or as a tool for decision makers to create and implement a strategy for urban sustainable development.

The building sector accounted for around a fourth of the total energy usage in Sweden in year 2010 (Energimyndigheten, 2012). Therefore it has become very interesting to achieve a lower energy usage in residential buildings. One way to achieve that is to build so called passive houses. By being very well insulated and have low leakage through the walls, they can reduce the energy usage for heating with a substantial amount. The first passive house was built during the 90’s in Germany; and in Sweden the first passive house was built in Gothenburg 2001. Both Sweden and EU have goals to reduce the overall energy usage and greenhouse emission by 2020 and 2050. The concept of the passive house is one way to achieve the goals. In short, the concept of the passive house in Sweden is: The air tightness for the walls should be tighter than 0,3 l/m2,s at 50 Pa overpressure The heat loss factor must not exceed 15 W/m2 Atemp for climate zone III The delivered energy must not exceed 50 kWh/m2 Atemp,year for purely non electrically heated systems in climate zone III The average u-value for windows should be as highest 0,8 W/m2,K. The term primary energy is a term that is frequently used in the EU when talking about energy usage. Apart from the above mentioned criteria, passive houses in Germany must also use less than 120 kWh/m2Atemp,year in primary energy. Primary energy usage for the passive houses is calculated by multiplying the energy usage with the respective primary energy factor. The primary energy factors were set to be the following: Electricity mix – 2,7 District heating mix – 0,79 District heating from waste – 0,04 Electricity from wind power – 0,05 The results show that the passive houses in Trettondagen and Oxtorget were the only ones that passed the German limit of 120 kWh/m2Atemp,year. The low energy usage in Trettondagen could be explained by the fact that the input values for calculating primary energy usage were simulated and not measured. Moreover, the passive house in Trettondagen was connected to the district heating from waste, which has a very low primary energy factor. The passive houses in Oxtorget were not connected to district heating and relied only on solar panels and heat recovery in the ventilation unit. An electric heater was installed in both the ventilation unit and the storage tank to provide extra heating. What set the passive house in Oxtorget apart from the others was that the electricity used in the houses only came from wind power. The low primary energy factor for wind power contributed to the extremely low primary energy of Oxtorget. The domestic electricity was relatively high in most of the passive houses, a reason to why they had problem with passing the German limit. One house had low enough domestic electricity usage to possibly pass the limit if the source of energy for heating was changed. It was the passive house in Falkenberg which was connected to district heating from biofuels (1,035). By switching to district heating from waste instead, the passive house in Falkenberg will then pass the limit. Primary energy usage for the passive houses in Oxtorget was also calculated with one half from electricity mix and the other half from electricity from wind power. Despite a large increase in primary energy, the passive houses still passed the limit. The passive house in Trettondagen was also calculated with switching district heating from waste to district heating mix. The primary energy increased a little bit but remained under the limit. The conclusion form this thesis showed that certain passive houses in Sweden were able to fall beneath the German limit for primary energy. One obstacle could be the high domestic electricity that has to decrease, perhaps by informing and involving the residents. Another problem is the absence of proper framework for calculating primary energy. There are some calculations mentioned in FEBY that resembles calculations for primary energy. The definitions though are too unclear and thus difficult to compare with the German standard.

Global concerns of climate change, increased greenhouse gas emissions and security of energy supply have accelerated the search for alternative energy sources both indeveloped and developing countries. Developing countries are now embracingutilization of biogas as a renewable energy option to meet some of their cooking andlighting needs. In Uganda, despite the introduction of biogas in the 1950’s, thetechnology has not received considerable acceptance and as a result its penetrationhas remained relatively low.  Several installed biogas plants have failed and those working are not working to theexpectation of the technicians and their owners. This research presents results of thestudy carried out to establish the performance of farm based biogas systems so as toassess the challenges faced by the users and to identify the possible causes of failurefor the non-operational systems.  A survey of 144 biogas plants was carried out after which performance monitoring ofselected digesters in the districts of Luwero, Kampala, Wakiso, Mbale, Jinja andMukono. It was found that 55% of the surveyed  biogas  plants  were  not  operational and  others  not  performing  to  the  users expectations. Most of the plants monitoredwere operating in the temperature range of 18°C-25°C with the gas quality rangingbetween 50-60% methane. Most digesters showed evidence of high organic loadingrates indicated by traces of biogas at the expansion chamber. The identified  causes of  failure  were  poor  system  maintenance, poor workmanship during constructionworks, poor  operation  practices, availability of other cheap fuel alternatives, lazinessand lack of interest amongst  the users, lack of alternative sources of feedstock andsystem blockages. Furthermore, there is need to sensitize people on the need for using alternativesources of energy such as biogas and improved cooking stoves for fuel saving as mostof them use wood and charcoal as supplementary fuels. This would reduce globalwarming through reduced deforestation and bring about environmental sustainabilityas a whole.

In this report we discuss the use of k-ε RANS (Reynolds-averaged Navier-Stokes equations) turbulence model for wind turbine applications. This model has been implemented in the new wind turbine wake CFD code that is being developed at ECN. Simulations of the wind turbine test site EWTW are compared with measurements conducted between 2005 and 2009 and with FarmFlow, ECN's current wind turbine wake code. Based on the results the uncertainties in the current approach are highlighted and areas for possible improvement are discussed.

The current energy scenario in the developing nations with abundant sun resource (e.g. southern Mediterranean countries of Europe, Middle-East & North Africa) relies mainly on fossil fuels to supply the increasing energy demand. Although this long adopted pattern ensures electricity availability on demand at all times through the least cost proven technology, it is highly unsustainable due to its drastic impacts on depletion of resources, environmental emissions and electricity prices. Solar thermal Hybrid power plants among all other renewable energy technologies have the potential of replacing the central utility model of conventional power plants, the understood integration of solar thermal technologies into existing conventional power plants shows the opportunity of combining low cost reliable power and Carbon emission reduction. A literature review on the current concentrating solar power (CSP) technologies and their suitability for integration into conventional power cycles was concluded, the best option was found be in the so called Integrated solar combined cycle systems (ISCCS); the plant is built and operated like a normal combined cycle, with a solar circuit consisting of central tower receiver and heliostat field adding heat to the bottoming Rankine cycle. A complete model of the cycle was developed in TRNSYS simulation software and Matlab environment, yearly satellite solar insolation data was used to study the effect of integrating solar power to the cycle throw-out the year. A multi objective thermo economic optimization analysis was conducted in order to identify a set of optimum design options. The optimization has shown that the efficiency of the combined cycle can be increased resulting in a Levelized electricity cost in the range of 10 -14 USDcts /Kwhe. The limit of annual solar share realized was found to be around 7 % The results of the study indicate that ISCCS offers advantages of higher efficiency, low cost reliable power and on the same time sends a green message by reducing the environmental impacts in our existing power plant systems.